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Mars Base

New Type of Star Explosion Discovered | Type Iax Supernovas | Space.com - 0 views

www.space.com/upernovas-star-explosions.html

scibyte88 Supernova

shared by Mars Base on 27 Mar 13 - No Cached
  • It remains unclear what precisely happens
  • The helium in the companion star's outer shell might undergo nuclear fusion, blasting a shock wave at the white dwarf that makes it detonate
  • On the other hand, all the helium the white dwarf accumulated from its companion star could alter the density and temperature of the white dwarf's interior, forcing carbon, oxygen and maybe helium within the star to fuse, triggering an explosion
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  • No Type Iax supernovas have been seen so far in elliptical galaxies, which are filled with old stars
Mars Base

New Kind of "Runt" Supernovae Could be Lurking Unseen - 0 views

www.universetoday.com/...rnovae-could-be-lurking-unseen

scibyte88 Supernova

shared by Mars Base on 27 Mar 13 - No Cached
  • Until now, supernovae have come in two main versions
  • In one scenario, a huge star, 10 to 100 times more massive as our Sun, collapses causing a colossal stellar explosion
  • Type Ia supernovae, occurs when material from a parent star streams onto the surface of a white dwarf. Over time, so much material falls onto the white dwarf that it raises the core temperature igniting carbon and causing a runaway fusion reaction. This event completely disrupts the white dwarf and results in a colossal stellar explosion
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  • Now astronomers have found a third type that is fainter and less energetic than a Type Ia. Called a Type Iax supernova
  • essentially a mini supernova
  • only about one-hundredth as bright as their supernova siblings
  • calculates that Type Iax supernovae are about as third as common as Type Ia supernovae
  • The researchers also did not find them in elliptical galaxies, filled with older stars, suggesting that Type Iax supernovae come from young star systems
  • team identified 25 examples of this new type of supernova
  • Based on observations, the team found that the new Type Iax supernovae come from binary star systems containing a white dwarf and a companion star that has burned all of its hydrogen, leaving an outer layer that is helium rich
  • not sure what triggers the Type Iax supernova
  • One explanation involves the ignition of the outer helium layer from the companion star. The resulting shockwave slams into the white dwarf and disrupts it, causing the explosion.
  • Alternately, the white dwarf might ignite first due to the overlying helium shell it has collected from the companion star.
  • it appears that in many cases the white dwarf survives the explosion unlike in a Type Ia supernova where the white dwarf is completely destroyed
  • Supernovae explosions release so much energy as heat and light that they outshine entire galaxies for brief periods of time
  • The extremely hot conditions naturally create new heavier elements, such as gold, lead, nickel, zinc and copper
  • Type Iax supernovas aren’t rare, they’re just faint
Mars Base

ScienceShot: A New Class of Supernova - ScienceNOW - 0 views

news.sciencemag.org/...shot-a-new-class-of-super.html

scibyte88 Supernova

shared by Mars Base on 27 Mar 13 - No Cached
  • type Iax, release somewhere between 1% and 50% the energy of a type Ia supernova
  • spectra of type Iax stars don't include any signs of hydrogen
  • Type Iax supernovae most likely form in binary star systems when a superdense, carbon- and oxygen-rich white dwarf star (center of disk at left) robs material from its helium-rich partner, eventually accumulating enough mass on its surface to trigger an explosion
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  • Astronomers likely have discovered so few type Iax supernovae only because they are faint, not because they are rare
  • estimates that for every 100 type Ia supernovae explosions that occur, there are about 31 type Iax supernovae
Mars Base

Wilkinson Microwave Anisotropy Probe - Wikipedia, the free encyclopedia - 0 views

en.wikipedia.org/...son_Microwave_Anisotropy_Probe

scibyte88 WMAP

shared by Mars Base on 31 Mar 13 - No Cached
  • a spacecraft which measures differences in the temperature of the Big Bang's remnant radiant heat – the Cosmic Microwave Background Radiation – across the full sky
  • The WMAP spacecraft was launched on June 30, 2001,
  • The WMAP mission succeeds the COBE space mission and was the second medium-class (MIDEX) spacecraft of the Explorer program.
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  • WMAP's measurements played the key role in establishing the current Standard Model of Cosmology
  • WMAP data are very well fit by a universe that is dominated by dark energy in the form of a cosmological constant
  • The anisotropies then are used to measure the universe's geometry, content, and evolution; and to test the Big Bang model, and the cosmic inflation theory
  • he map contains 3,145,728 pixels, and uses the HEALPix scheme to pixelize the sphere
  • The telescope's primary reflecting mirrors are a pair
  • that focus the signal onto a pair of
  • secondary reflecting mirrors.
  • shaped for optimal performance: a carbon fibre shell upon a Korex core, thinly-coated with aluminium and silicon oxide.
  • The secondary reflectors transmit the signals to the corrugated feedhorns that sit on a focal plane array box beneath the primary reflectors
  • The receivers are polarization-sensitive differential radiometers measuring the difference between two telescope beams.
  • To avoid collecting Milky Way galaxy foreground signals, the WMAP uses five discrete radio frequency bands
  • The WMAP's trajectory and orbit
  • The WMAP observes in five frequencies, permitting the measurement and subtraction of foreground contamination (from the Milky Way
  • Foreground contamination is removed in several ways
  • First, subtract extant emission maps from the WMAP's measurements; second, use the components' known, spectral values to identify them; third, simultaneously fit the position and spectra data of the foreground emission, using extra data sets
Mars Base

Radiolab Wants Your Help To Track The Once-Every-17-Year Cicada "Swarmageddon" | Popula... - 0 views

www.popsci.com/...ry-17-year-cicada-swarmageddon

scibyte88 Cicada

shared by Mars Base on 02 Apr 13 - No Cached
  • Magicicada is a genus of cicada with either a 13- or a 17-year lifespan, depending on species
  • t the Magicicada larvae live underground for nearly their entire lives, feeding on fluids from tree roots in the northeast United States, emerging with only a few weeks life in their lives
  • to molt into adults, mate, lay eggs, and die.
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  • we're not really sure why they use this life cycle strategy, but one guess is that such a long period between broods could fool predators, who likely won't have been alive (or won't remember) the previous emergence.
  • Brood II, also known as the "East Coast Brood," is a 17-year cicada due for emergence this summer
  • It ranges from the Virginia/North Carolina border up through the northern end of the New York City suburbs
  • Radiolab
  • radio shows/podcasts
  • has come up with a cicada tracker to pinpoint exactly when Brood II will begin "swarmageddon."
  • Radiolab will
  • monitor the soil temperature. When the soil eight inches below the surface reaches a steady temperature of 64 degrees F, the cicadas will begin their transformation
  • You can then report your findings to Radiolab, starting at the latest in mid-April
  • Radiolab's interactive map just when they'll emerge
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