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February 11 - Today in Science History - Scientists born on February 11th, died, and ev... - 0 views

todayinsci.com/2_11.htm

scibyte118 LookingBack LookingBackJan LookingBackFed

shared by Mars Base on 01 Feb 14 - No Cached
  • Ceres observation interruption
  • In 1801, Giuseppe Piazzi made a 24th observation of the position of Ceres, the asteroid he discovered between the orbits of Mars and Jupiter, on 1 Jan 1801. It was the first and largest of the dwarf planets now known. After this, it moved into the light of the Sun, and was lost to view for most of the rest of the year. To mathematically relocate Ceres, Carl Gauss, age 24, took up the challenge to calculate its orbital path, based on the limited number of observations available. His method was tedious, requiring 100 hours of calculation. He began with a rough approximation for the unknown orbit, and then used it to produce a refinement, which became the subject of another improvement.. And so on. Astronomers using them found his results in close agreement as they located Ceres again 25 Nov-31 Dec 1801.«
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

July 16 - Today in Science History - Scientists born on July 16th, died, and events - 0 views

www.todayinsci.com/...7_16.htm

scibyte136 LookingBackJul

shared by Mars Base on 15 Jul 14 - No Cached
  • Shoemaker-Levy Comet
  • In 1994, the first of 21 asteroids, major fragments of the comet Shoemaker-Levy 9 broken-up 2 years earlier, hit Jupiter, creating a 1200-mile wide fireball 600 miles high to the joy of astronomers awaiting the celestial fireworks, giving scientists their first chance to observe such a collision as it happened, and others through July 22. Jupiter is a gas giant, made up mostly of hydrogen and helium in gas and liquid form.When we observe Jupiter, we are looking not at a solid surface, but a banded atmosphere with swirling clouds and huge storms
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