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Mars Base

Distant planets' atmospheres revealed | Atom & Cosmos | Science News - 0 views

www.sciencenews.org/...t_planets_atmospheres_revealed

scibyte86 exoplanet

shared by Mars Base on 15 Mar 13 - No Cached
  • Astronomers have gotten the most detailed look yet at the atmosphere of a planet outside the solar system
  • The study is among the first to directly analyze the chemical makeup of an exoplanet
  • In the past, astronomers inferred the existence of exoplanets and their gases by looking for subtle changes in the light streaming from the planet’s star
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  • Now, with improved instruments, a team
  • has detected light coming directly from a planet light-years away
  • The data have high enough resolution to reveal not only the presence but the abundance of carbon monoxide and water in the planet’s atmosphere
  • Such information could shed light on how the planet formed
  • studies could also reveal the presence of life on a distant planet, but the planet’s size and orbit have already ruled it out as a habitable world
  • In 2008
  • the first image of a multiplanet system outside the solar system, showing three gas giants orbiting the star HR 8799
  • HR 8799 is about 130 light-years from Earth, in the constellation Pegasus
  • The planets are scorching hot, making them bright enough for astronomers to detect directly
  • In 2010, the researchers imaged a fourth planet around HR 8799
  • In the new study
  • focused on one of these planets, HR 8799c.
  • Five to 10 times as massive as Jupiter, HR 8799c sits about eight times farther away from its star than Jupiter does from the sun
  • Because of that great distance, the astronomers could block the star’s light and record infrared light
  • Because different gases absorb and emit light in distinct ways, the team could identify carbon monoxide and water but found no methane, which scientists had thought might be present.
  • In another new study
  • researchers simultaneously collected infrared light from the atmospheres of all four planets
  • A team led by
  • an astrophysicist at the American Museum of Natural History in New York City, found hints of ammonia, methane, carbon dioxide and acetylene in the planets’ atmospheres
  • The chemistry of each planet varies
  • different from anything in our own solar system
  • Although the teams looked at different wavelengths of light, which pick up different types of molecules, the two studies appear consistent
  • by peering at just one planet, Konopacky’s team obtained more detailed data that allowed the researchers to get a sense of how much carbon and oxygen is in HR 8799c’s atmosphere
  • Knowing the ratio of carbon to oxygen in the atmosphere may reveal how the planet formed
  • Astronomers have two competing theories of how planets arise from the disk of gas and dust encircling a young star
  • In the gravitational instability model, some of the gas and dust suddenly clumps and collapses, simultaneously creating a planet’s core and atmosphere
  • In this scenario, the chemical composition of a planet should match that of its star
  • In the other model, known as core accretion, planet building is a two-step process
  • First, material from the disk accumulates into a core.
  • Later, the core captures gases swirling in the disk to form an atmosphere.
  • In this case, the carbon-to-oxygen ratio of the planet may differ from the star because the accretion of cores may deplete the disk of certain elements
  • Compared with its star, HR 8799c appears to have slightly more carbon relative to oxygen, suggesting the planet originated via core accretion
  • surmise that when the disk around HR 8799 formed, water froze into particles of ice.
  • The bits of ice collided to form the planet’s core, leaving behind little water vapor, and therefore less oxygen, when the planet accumulated its atmosphere later on
  • Other researchers are not convinced by this conclusion
  • “We don’t really understand planetary formation enough to make a strong case either way,”
  • the data from both new studies may help astronomers refine their simulations of planetary formation
  • astronomers have directly imaged planets around three distant stars
  • researchers are poised to capture light from many more planets
  • Project 1640,
  • is looking for Jupiter-sized planets around some 200 stars
  • “Ultimately, with better instruments, people will be able to use these methods on Earthlike planets.”
Mars Base

Astronomers discover planet that shouldn't be there - 0 views

phys.org/...tronomers-planet-shouldnt.html

scibyte112 exoplanet

shared by Mars Base on 06 Dec 13 - No Cached
  • An international team of astronomers
  • has discovered the most distantly orbiting planet found to date around a single, sun-like star
  • 11 times Jupiter's mass and orbiting its star at 650 times the average Earth-Sun distance
  • ...34 more annotations...
  • HD 106906 b
  • throws a wrench in planet formation theories
  • no model of either planet or star formation fully explains what we see
  • It is thought that planets close to their stars, like Earth, coalesce from small asteroid-like bodies born in the primordial disk of dust and gas that surrounds a forming star
  • this process acts too slowly to grow giant planets far from their star
  • Another proposed mechanism is that giant planets can form from a fast, direct collapse of disk material
  • primordial disks rarely contain enough mass in their outer reaches to allow a planet like HD 106906 b to form
  • Several alternative hypotheses have been put forward, including formation like a mini binary star system
  • binary star system can be formed when two adjacent clumps of gas collapse more or less independently to form stars, and these stars are close enough to each other to exert a mutual gravitation attraction and bind them together in an orb
  • It is possible that in the case of the HD 106906 system the star and planet collapsed independently from clumps of gas, but for some reason the planet's progenitor clump was starved for material and never grew large enough to ignite and become a star
  • one problem with this scenario is that the mass ratio of the two stars in a binary system is typically no more than 10-to-1.
  • the mass ratio is more than 100-to-1,
  • extreme mass ratio is not predicted from binary star formation theories – just like planet formation theory predicts that we cannot form planets so far from the host star
  • is also of
  • interest because researchers can still detect the remnant "debris disk" of material left over from planet and star formation.
  • potential to help us disentangle the various formation models
  • Future observations of the planet's orbital motion and the primary star's debris disk may help answer that question
  • At only 13 million years old, this young planet still glows from the residual heat of its formation
  • Because at 2,700 Fahrenheit (about 1,500 degrees Celsius) the planet is much cooler than its host star
  • it emits most of its energy as infrared rather than visible light
  • Earth
  • formed 4.5 billion years ago
  • about 350 times older than HD 106906 b.
  • Direct imaging observations require exquisitely sharp images, akin to those delivered by the Hubble Space Telescope
  • To reach this resolution from the ground requires a technology called Adaptive Optics, or AO
  • The team used the new Magellan Adaptive Optics (MagAO) system and Clio2 thermal infrared camera
  • mounted on the 6.5 meter-diameter Magellan telescope in the Atacama Desert in Chile to take the discovery image
  • MagAO was able to utilize its special Adaptive Secondary Mirror
  • 585 actuators, each moving 1,000 times a second, to remove the blurring of the atmosphere
  • optimized for thermal infrared wavelengths, where giant planets are brightest compared to their host stars
  • planets are most easily imaged at these wavelengths
  • The team was able to confirm that the planet is moving together with its host star by examining Hubble Space Telescope data taken eight years prior for another research program
  • This planet discovery is particularly exciting because it is in orbit so far from its parent star. This leads to many
  • questions about its formation history and composition
Mars Base

Astronomers answer key question: How common are habitable planets? - 0 views

phys.org/...-common-habitable-planets.html

scibyte109

shared by Mars Base on 07 Nov 13 - No Cached
  • astronomers analyzed all four years of Kepler data in search of Earth-size planets in the habitable zones of sun-like stars
  • Based on this analysis, they estimate that 22 percent of stars like the sun have potentially habitable Earth-size planets, though not all may be rocky or have liquid water
  • NASA's Kepler spacecraft
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  • provided enough data to complete its mission objective: to determine how many of the 100 billion stars in our galaxy have potentially habitable planets
  • Based on a statistical analysis
  • astronomers now estimate that one in five stars like the sun have planets about the size of Earth and a surface temperature conducive to life.
  • nearly 20 years since the discovery of the first extrasolar planet around a normal star
  • Since then we have learned that most stars have planets of some size and that Earth-size planets are relatively common in close-in orbits that are too hot for life
  • Earth-size planets in Earth-size orbits are not necessarily hospitable to life, even if they orbit in the habitable zone of a star where the temperature is not too hot and not too cold
  • thick atmospheres, making it so hot at the surface that DNA-like molecules would not survive
  • rocky surfaces that could harbor liquid water suitable for living organisms
  • Last week,
  • provided hope that many such planets actually are rocky
  • NASA launched the Kepler space telescope in 2009 to look for planets that cross in front of, or transit, their stars, which causes a slight diminution – about one hundredth of one percent – in the star's brightness
  • 150,000 stars photographed every 30 minutes for four years
  • reported more than 3,000 planet candidates
  • the Keck Telescopes in Hawaii
  • help them determine each star's true brightness and calculate the diameter of each transiting planet, with an emphasis on Earth-diameter planets.
  • The team's definition of habitable is that a planet receives between four times and one-quarter the amount of light that Earth receives from the sun
  • Independently
  • focused on the 42,000 stars that are like the sun or slightly cooler and smaller, and found 603 candidate planets orbiting them
  • Only 10 of these were Earth-size, that is, one to two times the diameter of Earth and orbiting their star at a distance where they are heated to lukewarm temperatures suitable for life
  • Accounting for missed planets, as well as the fact that only a small fraction of planets are oriented so that they cross in front of their host star as seen from Earth, allowed them to estimate that 22 percent of all sun-like stars in the galaxy have Earth-size planets in their habitable zones.
  • All of the potentially habitable planets found in their survey are around K stars, which are cooler and slightly smaller than the sun
  • analysis shows that the result for K stars can be extrapolated to G stars like the sun
Mars Base

Kepler Team Finds System with Two Potentially Habitable Planets - 0 views

www.universetoday.com/...-potentially-habitable-planets

scibyte91 scibyte92 exoplanet

shared by Mars Base on 19 Apr 13 - No Cached
  • scientists analyzing data from NASA’s Kepler mission has found a planetary system with two small, potentially rocky planets that lie within the habitable zone of their star
  • Kepler-62, is a bit smaller and cooler than our Sun, and is home to a five-planet system
  • Two of the worlds, Kepler-62e and Kepler-62f are the smallest exoplanets yet found in a habitable zone, and they might both be covered in water or ice, depending on what kind of atmosphere they might have
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  • The curves show the mass-radius-relation (average density) for different types of planets
  • The blue line indicates
  • planets made mostly (75%) of water, the black line that of planets like our Earth that consist almost exclusively of rock (
  • estimate of their mass places them in a region (blue areas) where it is highly probable for them to be earth-like planets, that is: planets with a solid (if possibly covered in water) surface
  • the empirical habitable zone, liquid water can exist on the surface of a planet if that planet has sufficient cloud cover. In the narrow habitable zone, liquid water can exist on the surface even without the presence of a cloud cover
  • while the sizes of Kepler 62e and 62f are known, their mass and densities are not.
  • every planet found in their size range so far has been rocky, like Earth
  • Life on these worlds would be under water with no easy access to metals, to electricity, or fire for metallurgy
  • life’s inventiveness to get to a technology stage will surprise us
  • Kepler-62e would have a bit more clouds than Earth according to computer models
  • More distant Kepler-62f would need the greenhouse effect from plenty of carbon dioxide to warm it enough to host an ocean
  • Kepler-62e probably has a very cloudy sky and is warm and humid all the way to the polar regions
  • Kepler-62f would be cooler, but still potentially life-friendly
  • the two would exhibit distinctly different colors and make our search for signatures of life easier on such planets in the near future
  • planets in the habitable zone were until now discovered by what is known as the radial velocity method
  • gives you a lower limit for the planet’s mass, but no information about its radius
  • What makes Kepler-62e and Kepler-62f so exciting is
  • We know their radius, which indicates that these are indeed rocky planets, and they orbit their star in the habitable zone
  • makes it difficult to assess whether or not a planet is rocky, like the Earth. A small radius (less than 2 Earth radii), on the other hand, is a strong indicator that a planet around is indeed rocky – unless we are talking about a planet around a very young star
Mars Base

Kepler Explorer app puts distant planets at your fingertips - 0 views

www.physorg.com/...lorer-app-distant-planets.html

scibyte41 Kepler app

shared by Mars Base on 04 Apr 12 - No Cached
  • Kepler Explorer app puts distant planets at your fingertips
  • Kepler Explorer challenges users to design a planet that matches the Kepler data
  • Armchair explorers of the cosmos can now have at their fingertips the nearly 2,000 distant planetary systems discovered by NASA's Kepler Mission
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  • innovative app for iPads and iPhones
  • available for free
  • brought together faculty and students in astrophysics, art, and technology for a summer institute last year
  • team quickly settled on the idea to create an app, and also developed it into an exhibit that provides additional information and shows the app's output on a large screen
  • scheduled for long-term installation in the Lick Observatory visitors gallery later this month
  • Kepler Explorer starts with drop-down menus listing all the Kepler-discovered planetary systems, plus our own solar system
  • selected system is displayed in a view that shows the planet or planets in their orbits around the host star
  • Shown in real time the planets look motionless, but moving a slider increases the speed until the planets zip around their star
  • lets users zoom in and move around the system, and tapping on an individual planet brings it up for further exploration. Another view shows the relative sizes of the individual planets compared to their host star
  • when viewing individual planets
  • The user can manipulate the composition of the planet and its atmosphere and see which mixtures of components (iron, rock, water, and hydrogen) are consistent with Kepler's observations
  • represents graphically the type of in-depth analysis that Fortney does for the Kepler Mission
  • the app allows anyone to explore the properties of many different planets very quickly
  • only measures the radius of a planet, or how big it is. In most cases, the mass of the planet is unknown
  • there may be different combinations of components that result in a planet of a given size
  • 's interactive graphics show how this works
  • sliders for different components and how they are partitioned in the core and the atmosphere, and as you move the sliders the image of the planet grows and shrinks, based on hundreds of calculations
  • the app tells you when the size of your planet matches the observations
  • calculations involved took hours of computer time, but the results are stored in tables so the app can use them on the fly.
Mars Base

Astronomers Discover 18 Huge New Alien Planets | Alien Planets & Solar Systems | Gas Gi... - 0 views

www.space.com/en-planets-keck-telescope.html

scibyte24

shared by Mars Base on 03 Dec 11 - No Cached
  • Astronomers have found 18 new alien planets, all of them Jupiter-size gas giants that circle stars bigger than our sun
  • increase the number of known planets orbiting massive stars by 50 percent
  • should also help astronomers better understand how giant planets form and grow
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  • just a few months after a different team of researchers announced the discovery of 50 newfound alien worlds
  • including one rocky planet that could be a good candidate for life
  • list of known alien planets is now well over 700 and climbing fast
  • researchers surveyed about 300 stars using the Keck Observatory in Hawaii and instruments in Texas and Arizona
  • focused on so-called "retired" type A stars that are at least 1.5 times more massive than our own sun
  • just beyond the main stage of life — hence the name "retired"
  • ballooning out to become what's known as subgiant stars
  • scrutinized these stars, looking for slight wobbles caused by the gravitational tug of orbiting planets
  • revealed 18 new alien worlds
  • All 18 planets also orbit relatively far from their stars, at a distance of at least 0.7 times the span from Earth to the sun (about 93 million miles, or 150 million kilometers
  • the new finds lend support to one of two theories that attempt to explain the formation and evolution of planets
  • core accretion, posits that planets grow as gas and dust glom onto seed particles in a protoplanetary disk.
  • predicts that the characteristics of a planetary system — the number and size of planets, for example — depend strongly on the mass of the star
  • competing theory, called gravitational collapse, holds that planets form when big clouds of gas and dust in the disk spontaneously collapse into clumps that become planets
  • According to this idea, stellar mass should have little impact on planet size, number and other characteristics
  • it seems that stellar mass does in fact play an important role
Mars Base

Should This Alien World Even Exist? This Young Disk Could Challenge Planet-Formation Th... - 0 views

www.universetoday.com/...enge-planet-formation-theories

scibyte98 exoplanet

shared by Mars Base on 14 Jun 13 - No Cached
  • gap in the cloud? That could be a planet being born some 176 light-years away from Earth
  • small planet, only 6 to 28 times Earth’s mass.
  • This alien world, if we can confirm it, shouldn’t be there according to conventional planet-forming theory
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  • The gap in the image above — taken by the Hubble Space Telescope — probably arose when a planet under construction swept through the dust and debris in its orbit
  • That’s not much of a surprise (at first blush) given what we think we know about planet formation
  • You start with a cloud of debris and gas swirling around a star, then gradually the bits and pieces start colliding, sticking together and growing bigger into small rocks, bigger ones and eventually, planets or gas giant planet cores
  • this planet is a heck of a long way from its star, TW Hydrae, about twice Pluto’s distance from the sun
  • Given that alien systems’ age, that world shouldn’t have formed so quickly.
  • Astronomers believe that Jupiter took about 10 million years to form at its distance away from the sun
  • This planet near TW Hydrae should take 200 times longer to form because the alien world is moving slower, and has less debris to pick up
  • because TW Hydrae‘s system is believed to be only 8 million years old.
  • TW Hydrae is only 55 percent as massive as our sun
  • astronomers are seriously investigating other theories
  • One alternative brought up in the press release: perhaps part of the disc collapsed due to gravitational instability
  • If that is the case, a planet could come to be in only a few thousand years, instead of several million
  • add to planet formation theories as to how you can actually form a planet very far out
  • If we can actually confirm that there’s a planet there, we can connect its characteristics to measurements of the gap properties
  • direct collapse” theory, though: astronomers believe it takes a bunch of matter that is one to two times more massive than Jupiter before a collapse can occur to form a planet
  • this world is no more than 28 times the mass of Earth, as best as we can figure
  • Jupiter itself is 318 times more massive than Earth
  • There are also intriguing results about the gap
  • dust grains in this system, orbiting nearby the gap, are still smaller than the size of a grain of sand
  • Astronomers plan to use ALMA and the James Webb Space Telescope, which should launch in 2018, to get a better look
Mars Base

Alien Super-Earth Light Seen for 1st Time | Exoplanet Search | Space.com - 0 views

www.space.com/light-detected-55-cancrie.html

scibyte45 exoplanet Spitzer

shared by Mars Base on 09 May 12 - No Cached
  • Light from an alien "super-Earth" twice the size of our own Earth has been detected by a NASA space telescope for the first time
  • spotted light from the alien planet 55 Cancri e, which orbits a star 41 light-years from Earth
  • A year on the extrasolar planet lasts just 18 hours
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  • 55 Cancri e was first discovered in 2004 and is not a habitable world
  • The world is about twice the width of Earth and is super-dense, with about eight times the mass of Earth.
  • until now, scientists have never managed to detect the infrared light from the super-Earth world.
  • pioneering the study of atmospheres of distant planets and paving the way for NASA's upcoming James Webb Space Telescope
  • Spitzer first detected infrared light from an alien planet in 2005
  • that world was "hot Jupiter," a gas giant planet much larger than 55 Cancri e that orbited extremely close to its parent star
  • other telescopes have performed similar feats
  • Spitzer's view of the 55 Cancri e is the first time the light from a rocky super-Earth type planet has been seen
  • Since the discovery of 55 Cancri e, astronomers have pinned down increasingly strange features about the planet
  • already knew it was part of an alien solar system containing five exoplanets centered on the star 55 Cancri in the constellation Cancer
  • But 55 Cancri e stood out because it is ultra-dense and orbits extremely close to its parent star
  • 26 times closer than the distance between Mercury and our own sun
  • observations revealed that the star-facing side of 55 Cancri e
  • temperatures reaching up to 3,140 degrees Fahrenheit (1,726 degrees Celsius).
  • likely a dark world that lacks the substantial atmosphere needed to warm its nighttime side
  • the planet is oozing
  • Past observations of the planet by the Spitzer Space Telescope have suggested that one-fifth of 55 Cancri e is made up of lighter elements, including water
  • the extreme temperatures and pressures on 55 Cancri e would create what scientists call a "supercritical fluid" state
  • Supercritical fluids can be imagined as a gas in a liquid state, which can occur under extreme pressures and temperatures
  • On Earth, water can become a supercritical fluid inside some steam engines.
  • This graphic illuminates the process by which astronomers using NASA's Spitzer Space Telescope have for the first time detected the light from a super-Earth planet, the alien world of 55 Cancri e 41 light-years from Earth.
  • planet is likely a rocky world covered with water in a supercritical fluid state and topped off with a steam blanket
  • could be very similar to Neptune, if you pulled Neptune in toward our sun and watched its atmosphere boil away
  • detailed in the Astrophysical Journal
  • Spitzer Space Telescope launched in 2003
  • telescope engineers modified several settings on the observatory to optimize its alien planet vision
  • conceived of Spitzer more than 40 years ago
Mars Base

Billions of Habitable Worlds Likely in the Milky Way - 0 views

www.universetoday.com/...worlds-likely-in-the-milky-way

scibyte40 exoplanet

shared by Mars Base on 28 Mar 12 - No Cached
  • results from a new study that searched for rocky planets in the habitable zones around red dwarf stars
  • now estimates that there are tens of billions of such planets in the Milky Way galaxy
  • probably about one hundred in the Sun’s immediate neighborhood, less than 30 light years away.
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  • new observations with HARPS mean that about 40% of all red dwarf stars have a super-Earth orbiting in the habitable zone where liquid water can exist on the surface of the planet
  • first direct estimate of the number of smaller, rocky planets around red dwarf stars
  • another recent finding which suggested that every star in our night sky has at least one planet circling it — which didn’t include red dwarf stars – and our galaxy could be teeming with worlds
  • HARPS team surveyed a carefully chosen sample of 102 red dwarf stars in the southern skies over a six-year period
  • total of nine super-Earths (planets with masses between one and ten times that of Earth) were found, including two inside the habitable zones of Gliese 581 and Gliese 667 C respectively
  • combining all the data, including observations of stars that did not have planets, and looking at the fraction of existing planets that could be discovered, the team has been able to work out how common different sorts of planets are around red dwarfs
  • find that the frequency of occurrence of super-Earths in the habitable zone is 41% with a range from 28% to 95%.
  • Less than 12% of red dwarfs are expected to have giant planets (with masses between 100 and 1000 times that of the Earth).
  • habitable zone around a red dwarf, where the temperature is suitable for liquid water to exist on the surface, is much closer to the star than the Earth is to the Sun
  • But red dwarfs are known to be subject to stellar eruptions or flares, which may bathe the planet in X-rays or ultraviolet radiation, and which may make life there less likely.”
  • Gliese 667 Cc. This is the second planet in this triple star system and seems to be situated close to the center of the habitable zone
  • this planet is more than four times heavier than the Earth it is the closest twin to Earth found so far and almost certainly has the right conditions for the existence of liquid water on its surface
  • second super-Earth planet inside the habitable zone of a red dwarf
Mars Base

A planetary system from the early Universe - 0 views

www.physorg.com/...-planetary-early-universe.html

scibyte40 exoplanet

shared by Mars Base on 28 Mar 12 - No Cached
  • A group of European astronomers has discovered an ancient planetary system that is likely to be a survivor from one of the earliest cosmic eras, 13 billion years ago. The system consists of the star HIP 11952 and two planets, which have orbital periods of 290 and 7 days, respectively. Whereas planets usually form within clouds that include heavier chemical elements, the star HIP 11952 contains very little other than hydrogen and helium. The system promises to shed light on planet formation in the early universe – under conditions quite different from those of later planetary systems, such as our own
  • widely accepted that planets are formed in disks of gas and dust that swirl around young stars
  • many open questions remain
  • ...25 more annotations...
  • what it actually takes to make a planet
  • With a sample of, by now, more than 750 confirmed planets
  • astronomers have some idea of the diversity among planetary systems
  • certain trends have emerged
  • Statistically, a star that contains more “metals” - in astronomical parlance, the term includes all chemical elements other than hydrogen and helium – is more likely to have planets.
  • suggests a key question
  • Originally, the universe contained almost no chemical elements other than hydrogen and helium
  • what about planet formation under conditions like those of the very early universe
  • ? If metal-rich stars are more likely to form planets
  • stars with a metal content so low that they cannot form planets at all
  • then when
  • should we expect the very first planets to form
  • a group of astronomers
  • has discovered a planetary system that could help provide answers to those questions
  • part of a survey targeting especially metal-poor stars
  • identified two giant planets around a star known by its catalogue number as HIP 11952
  • at a distance of about 375 light-years from Earth
  • these planets
  • are not unusual
  • What is unusual is the fact that they orbit such an extremely metal-poor and, in particular, such a very old star!
  • planets around such a star should be extremely rare
  • Compared to other exoplanetary systems
  • not only one that is extremely metal-poor
  • at an estimated age of 12.8 billion years, also one of the oldest systems known so far.
  • In 2010 we found the first example of such a metal-poor system, HIP 13044. Back then, we thought it might be a unique case; now, it seems as if there might be more planets around metal-poor stars than expected
Mars Base

NASA Space Telescopes Find Patchy Clouds on Exotic World - NASA Jet Propulsion Laboratory - 0 views

www.jpl.nasa.gov/...news.php

scibyte105 exoplanet

shared by Mars Base on 05 Oct 13 - No Cached
  • Astronomers using data from NASA's Kepler and Spitzer space telescopes have created the first cloud map of a planet
  • known as Kepler-7b
  • Previous studies from Spitzer have resulted in temperature maps of planets orbiting other stars
  • ...21 more annotations...
  • this is the first look at cloud structures on a distant world.
  • observing this planet with Spitzer and Kepler for more than three years, we were able to produce a very low-resolution 'map' of this giant, gaseous planet
  • wouldn't expect to see oceans or continents on this type of world, but we detected a clear, reflective signature that we interpreted as clouds
  • Kepler-7b was one of the first
  • Kepler's visible-light observations of Kepler-7b's moon-like phases led to a rough map of the planet that showed a bright spot on its western hemisphere
  • data were not enough on their own to decipher whether the bright spot was coming from clouds or heat
  • Spitzer Space Telescope played a crucial role in answering this question
  • Spitzer can fix its gaze at a star system as a planet orbits around the star, gathering clues about the planet's atmosphere
  • Spitzer's ability to detect infrared light means it was able to measure Kepler-7b's temperature, estimating it to be between 1,500 and 1,800 degrees Fahrenheit (1,100 and 1,300 Kelvin).
  • relatively cool for a planet that orbits so close to its star -- within 0.06 astronomical units (one astronomical unit is the distance from Earth and the sun)
  • , too cool to be the source of light Kepler observed.
  • Instead, they determined, light from the planet's star is bouncing off cloud tops located on the west side of the planet.
  • Kepler-7b reflects much more light than most giant planets we've found, which we attribute to clouds in the upper atmosphere
  • the cloud patterns on this planet do not seem to change much over time -- it has a remarkably stable climate
  • With Spitzer and Kepler together, we have a multi-wavelength tool for getting a good look at planets that are trillions of miles away
  • exoplanet science
  • moving beyond just detecting exoplanets, and into the exciting science of understanding them
  • observations of Kepler-7b previously revealed that it is one of the puffiest planets known: if it could somehow be placed in a tub of water, it would float
  • found to whip around its star in just less than five days
  • a fully rendered 3D visualization tool, available for download at http://eyes.nasa.gov/exoplanets
  • program is updated daily with the latest findings from NASA's Kepler mission and ground-based observatories around the world as they search for planets
Mars Base

Potentially habitable Earth-like planet discovered; May have similar temperatures to ou... - 0 views

www.sciencedaily.com/...140630133425.htm

scibyte135 exoplanet

shared by Mars Base on 01 Jul 14 - No Cached
  • A potentially habitable Earth-like planet that is only 16 light years away has been discovered
  • The "super-Earth" planet, GJ 832 c, takes 16 days to orbit its red-dwarf star
  • has a mass at least five times that of Earth.
  • ...10 more annotations...
  • It receives about the same average stellar energy as Earth does and may have similar temperatures to our planet
  • These characteristics put it among the top three most Earth-like planets
  • It receives about the same average stellar energy as Earth does, because red dwarfs shine more dimly than our Sun, and may have similar temperatures to our planet
  • These characteristics put it among the top three most Earth-like planets, according to the Earth Similarity Index developed by scientists at the University of Puerto Rica in Arecibo
  • research group
  • says that if the planet has a similar atmosphere to Earth it may be possible for life to survive, although seasonal shifts would be extreme
  • "However, given the large mass of the planet, it seems likely that it would possess a massive atmosphere, which may well render the planet inhospitable
  • A denser atmosphere would trap heat and could make it more like a super-Venus and too hot for life," says Professor Tinney.
  • The planet was discovered from its gravitational pull on its parent star, which causes the star to wobble slightly
  • This team had previously found, in 2009, that the star has a cold Jupiter-like planet with a near-circular orbit of about nine years, called Gliese GJ b.
Chris Fisher

NASA's Kepler Announces 11 Planetary Systems Hosting 26 Planets - Mainpage - 0 views

www.naturenplanet.com/...-planetary-systems-hosting.htm

nasa Kepler planets

shared by Chris Fisher on 25 Mar 12 - No Cached
  • NASA's Kepler mission has discovered 11 new planetary systems hosting 26 confirmed planets. These discoveries nearly double the number of verified planets and triple the number of stars known to have more than one planet that transits, or passes in front of, the star.
  • The planets orbit their host star once every six to 143 days. All are closer to their host star than Venus is to our sun.
  • Chris Fisher on 25 Mar 12
     
    NASA's Kepler mission has discovered 11 new planetary systems hosting 26 confirmed planets. These discoveries nearly double the number of verified planets and triple the number of stars known to have more than one planet that transits, or passes in front of, the star. 
Mars Base

Astronomers find a new type of planet: The 'mega-Earth' - 0 views

phys.org/...onomers-planet-mega-earth.html

scibyte134 exoplanet

shared by Mars Base on 05 Jun 14 - No Cached
  • Astronomers announced
  • that they have discovered a new type of planet - a rocky world weighing 17 times as much as Earth
  • Theorists believed such a world couldn't form because anything so hefty would grab hydrogen gas as it grew and become a Jupiter-like gas giant
  • ...28 more annotations...
  • This planet, though, is all solids and much bigger than previously discovered "super-Earths," making it a "mega-Earth."
  • Kepler-10c, circles a sunlike star once every 45 days
  • It is located about 560 light-years from Earth in the constellation Draco
  • The system also hosts a 3-Earth-mass "lava world," Kepler-10b, in a remarkably fast, 20-hour orbit
  • Kepler-10c was originally spotted by NASA's Kepler spacecraft.
  • By measuring the amount of dimming, astronomers can calculate the planet's physical size or diameter
  • Kepler can't tell whether a planet is rocky or gassy
  • Kepler-10c was known to have a diameter
  • , 2.3 times as large as Earth
  • This suggested it fell into a category of planets known as mini-Neptunes, which have thick, gaseous envelopes
  • The team used the HARPS-North instrument on the Telescopio Nazionale Galileo (TNG) in the Canary Islands to measure the mass of Kepler-10c
  • They found that it weighed 17 times as much as Earth - far more than expected.
  • This showed that Kepler-10c must have a dense composition of rocks and other solids.
  • Planet formation theories have a difficult time explaining how such a large, rocky world could develop
  • The early universe contained only hydrogen and helium
  • Heavier elements needed to make rocky planets, like silicon and iron, had to be created
  • When those stars exploded
  • scattered
  • through space, which then could
  • later generations of stars and planets
  • This process should have taken billions of years. However, Kepler-10c shows that the universe was able to form such huge rocks even during the time when heavy elements were scarce.
  • tells us that rocky planets could form much earlier than we thought. And if you can make rocks
  • This research implies that astronomers shouldn't rule out old stars when they search for Earth-like planets
  • if old stars can host rocky Earths too, then we have a better chance of locating potentially habitable worlds in our cosmic neighborhood
  • The Kepler-10 system is about 11 billion years old, which means it formed less than 3 billion years after the Big Bang
  • It's massive enough to have held onto
  • its atmosphere
  • if it ever had it
Mars Base

Kepler wraps prime mission, begins extension - 0 views

phys.org/...r-prime-mission-extension.html

scibyte72 Kepler

shared by Mars Base on 15 Nov 12 - No Cached
  • NASA is marking two milestones in the search for planets like Earth; the successful completion of the Kepler Space Telescope's three-and-a-half-year prime mission and the beginning of an extended mission that could last as long as four years.
  • identify more than 2,300 planet candidates and confirm more than 100 planets
  • hundreds of Earth-size planet candidates have been found
  • ...14 more annotations...
  • Highlights from the prime mission
  • confirmed the discovery of the first planetary system with more than one planet transiting the same star
  • the discovery of the first unquestionably rocky planet outside the solar system
  • 1.4 times the size of Earth
  • confirmed the existence of a world with a double sunset
  • discoveries of six additional worlds orbiting double stars further demonstrated planets can form and persist in the environs of a double-star system
  • first planet in a habitable zone
  • December 2011
  • September 2011
  • February 2012
  • transiting planet candidates
  • total of 2,321
  • Recently
  • The joint effort of amateur astronomers and scientists led to the first reported case of a planet orbiting a double star
Mars Base

Gone perhaps, but Kepler won't soon be forgotten | Atom & Cosmos | Science News - 0 views

www.sciencenews.org/..._Kepler_wont_soon_be_forgotten

scibyte95 Kepler

shared by Mars Base on 25 May 13 - No Cached
  • When scientists at the Harvard-Smithsonian Center for Astrophysics scheduled a conference called “Exoplanets in the Post-Kepler Era,” they figured that era would still be several years away
  • . When
  • Kepler into space
  • ...23 more annotations...
  • astronomers knew that the galaxy contained at least 350 exoplanets, nearly all of them the size of Jupiter or larger
  • Kepler’s then spent four years
  • added nearly 3,000 planets
  • It will take at least several weeks before they beam commands up to the $600-million telescope, and they admit that a fix is a long shot.
  • Kepler engineers
  • strategizing about how to remotely repair one of two broken reaction wheels that precisely point the telescope
  • astronomers are convinced that the Milky Way contains hundreds of billions of planets, roughly one for every star, with at least 17 billion of them Earth-sized
  • NASA’s next exoplanet-hunting mission, the Transiting Exoplanet Survey Satellite, which is scheduled for a 2017 launch
  • Whereas Kepler has fixed its gaze on distant stars, TESS will focus on bright, nearby stars so that powerful telescopes like the upcoming James Webb Space Telescope will be able to probe the atmospheres of planets that TESS discovers
  • s TESS
  • while less sensitive than Kepler, will nonetheless uncover plenty of planets in our neighborhood, including a handful of Earth-sized worlds
  • Astronomers
  • Other astronomers
  • are still optimistic. They have a year of data from the telescope left to analyze
  • quite possibly including an Earth-sized planet orbiting a sunlike star at a distance suitable for life
  • Astronomers hope to pair size measurements of planets observed by telescopes such as TESS with mass readings from ground-based scopes that look for subtle wobbles in stars’ motion caused by the gravitational pull of orbiting planets.
  • Several years ago
  • radial velocity, could pick out only hulking planets that delivered a hard yank to their stars
  • lately the technology has improved so drastically that in October 2012, the High Accuracy Radial velocity Planet Searcher instrument
  • spotted what appears to be a planet only slightly heavier than Earth tightly orbiting Alpha Centauri B, a sunlike star a mere 4.4 light-years away
  • Kepler’s main goal was to determine the frequency of Earthlike planets in the galaxy
  • have enough data to make an intelligent extrapolation about what that number is, but
  • actually determining that number
Mars Base

Most Earthlike planets yet seen bring Kepler closer to its holy grail | Atom & Cosmos |... - 0 views

www.sciencenews.org/...epler_closer_to_its_holy_grail

scibyte91 scibyte92 exoplanet

shared by Mars Base on 19 Apr 13 - No Cached
  • five-planet system around a star called Kepler-62, some 1,200 light-years away in the constellation Lyra
  • Astronomers found the planets by analyzing nearly three years’ worth of data
  • Kepler-62e and Kepler-62f are far more accommodating. They are 1.6 and 1.4 times the diameter of Earth
  • ...19 more annotations...
  • early evidence supports the optimistic view that at least 62f is rocky
  • biggest uncertainty about both planets is their composition
  • an astronomer at the University of Washington
  • not involved in the research
  • Kepler-62e
  • may be too close to its star – and therefore too hot – to sustain life
  • if 62e is a rocky planet, it’s almost certainly tidally locked with its star, with one half of its surface always illuminated and the other perpetually dark
  • Kepler 62 is about two-thirds the size of the sun and several hundred degrees Celsius cooler
  • Finding planets in the habitable zones of larger stars
  • harder because those planets have relatively long orbits and barely cast a shadow as they pass across the faces of their suns
  • another study
  • led by
  • NASA Ames Research Center
  • identified two planets around a sunlike star called Kepler-69, some 2,700 light-years away
  • One of the planets is 1.7 times the size of Earth and teeters on the inner edge of the habitable zone
  • probably too hot for life
  • almost certainly a super-Venus rather than a super-Earth
  • even a planet 75 percent larger than Earth is potentially habitable
  • Next-generation missions like the Transiting Exoplanet Survey Satellite, which NASA approved earlier this month for launch in 2017, will take on the task of finding nearer planets that astronomers can study in depth
Mars Base

New look at HD 10180 shows it might have nine planets - 0 views

phys.org/...2012-04-hd-planets.html

scibyte42 exoplanet

shared by Mars Base on 09 Apr 12 - No Cached
  • after looking at data regarding the solar system surrounding the star HD 10180, that it likely has nine planets making it the most highly populated solar system known to man
  • after studying slight wobbles by the star as it’s tugged by planetary gravitation, he found what he believes is confirmation of a seventh planet, and evidence for two more
  • HD 10180 is about 130 light years away from us
  • ...17 more annotations...
  • first noted by astronomers in 2010
  • it was thought the solar system consisted of just five planets
  • speculation that it might have as many as seven
  • other work has shown that there are likely six planets, five of which are believed to have a mass close to that of Neptune
  • other appears closer in mass to Saturn
  • to these conclusions by studying the way a star appears to wobble (a Doppler shift
  • studying these light shifts, astronomers can deduce not only the size of the planet that causes it, but its period as well
  • didn’t make any new observations
  • he went back and looked at the original data using different kinds of statistical analysis techniques
  • found evidence for three more planets, all much smaller than the original six
  • estimates to be 1.3, 1.9, and 5.1 times the size of Earth
  • much shorter periods (1.2, 10 and 68 days) than
  • they are very close to their star, closer even than Mercury is to our sun
  • far too hot to support water retention or life, at least as we know it.
  • doesn’t actually prove that any of the planets suspected of revolving around HD 10180 actually exist
  • merely offers strong evidence
  • statistical evidence offered by Tuomi suggesting that if there are truly planets there, they all appear to have stable orbits.
Mars Base

Odd Alien Planets So Close Together They See 'Planetrise' | Kepler Mission | Space.com - 0 views

www.space.com/s-close-orbits-planetrise.html

scibyte52 exoplanets

shared by Mars Base on 22 Jun 12 - No Cached
  • Astronomers have discovered two alien planets around the same star whose orbits come so close together that each rises in the night sky of its sister world
  • ,200 light-years from Earth
  • differ greatly in size and composition but come within just 1.2 million miles (1.9 million kilometers) of each other, closer than any other pair of planets known,
  • ...15 more annotations...
  • Kepler-36b, appears to be a rocky "super-Earth" 4.5 times as massive as our planet
  • Kepler-36c, is a gaseous, Neptune-size world about eight times as massive as Earth
  • planets meet up every 97 days in a conjunction that would make each dramatically visible in the other's sky.
  • At their closest approach, the two planets are separated by five times the distance between the Earth and the moon
  • as different in density as Earth and Saturn
  • Kepler-36b and c are actually more like 20 times closer together than any two planets in our neck of the woods
  • Kepler-36c, which is about 3.7 times wider than Earth, likely has a rocky core surrounded by a substantial atmosphere filled with lots of hydrogen and helium
  • Kepler-36b, on the other hand, is a super-Earth just 1.5 times wider than our planet. Iron likely constitutes about 30 percent of its mass, water around 15 percent and atmospheric hydrogen and helium less than 1 percent
  • Kepler-36c orbits once every 16 days, at an average distance of 12 million miles (19 million km). Kepler-36b orbits each 14 days and sits about 11 million miles (18 million km) from the star.
  • Kepler-36b probably formed relatively close to the star
  • Kepler-36c likely took shape farther out
  • large-scale migrations that can bring initially far-flung planets much closer together
  • Kepler-36b probably sporting lava flows on its surface
  • orbit roughly three times closer to their host star, known as Kepler-36a, than the hellishly hot planet Mercury does to our sun
  • Kepler-36a is likely a bit hotter than our star
Mars Base

Faraway moon or faint star? Possible exomoon found - 0 views

phys.org/...y-moon-faint-star-exomoon.html

scibyte126 exoplanets

shared by Mars Base on 11 Apr 14 - No Cached
  • NASA-funded researchers have spotted the first signs of an "exomoon," and though they say it's impossible to confirm its presence
  • The discovery was made by watching a chance encounter of objects in our galaxy, which can be witnessed only once
  • won't have a chance to observe the exomoon candidate again
  • ...29 more annotations...
  • can expect more unexpected finds like this.
  • international study
  • using telescopes
  • technique, called gravitational microlensing, takes advantage of chance alignments between stars
  • When a foreground star passes between us and a more distant star, the closer star can act like a magnifying glass to focus and brighten the light of the more distant one
  • These brightening events usually last about a month
  • If the foreground star—or what astronomers refer to as the lens—has a planet circling around it, the planet will act as a second lens to brighten or dim the light even more
  • carefully scrutinizing these brightening events, astronomers can figure out the mass of the foreground star relative to its planet.
  • the foreground object could be a free-floating planet, not a star
  • astronomers are actively looking for exomoons—for example, using data from NASA's Kepler mission - so far, they have not found any.
  • In the new study, the nature of the foreground, lensing object is not clear. The ratio of the larger body to its smaller companion is 2,000 to 1.
  • That means the pair could be either a small, faint star circled by a planet about 18 times the mass of Earth—or a planet more massive than Jupiter coupled with a moon weighing less than Earth.
  • astronomers have no way of telling which of these two scenarios is correct
  • One possibility is for the lensing system to be a planet and its moon
  • The answer to the mystery lies in learning the distance to the circling duo
  • A lower-mass pair closer to Earth will produce the same kind of brightening event as a more massive pair located farther away
  • once a brightening event is over, it's very difficult to take additional measurements of the lensing system and determine the distance
  • The true identity of the exomoon candidate and its companion, a system dubbed MOA-2011-BLG-262, will remain unknown
  • In the future, however, it may be possible to obtain these distance measurements during lensing events
  • NASA's Spitzer and Kepler space telescopes, both of which revolve around the sun in Earth-trailing orbits, are far enough away from Earth to be great tools for the parallax-distance technique.
  • The basic principle of parallax can be explained by holding your finger out, closing one eye after the other, and watching your finger jump back and forth
  • A distant star, when viewed from two telescopes spaced really far apart, will also appear to move
  • When combined with a lensing event, the parallax effect alters how a telescope will view the resulting magnification of starlight
  • Though the technique works best using one telescope on Earth and one in space, such as Spitzer or Kepler, two ground-based telescopes on different sides of our planet can also be used
  • Meanwhile, surveys
  • are turning up more and more planets
  • These microlensing surveys have discovered dozens of exoplanets so far, in orbit around stars and free-floating
  • A previous NASA-funded study, also led by the MOA team, was the first to find strong evidence for planets the size of Jupiter roaming alone in space, presumably after they were kicked out of forming planetary systems
  • The new exomoon candidate, if real, would orbit one such free-floating planet.
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