Category Archives: stars, nebula, galaxies

Tellurium in the distance

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Nearly 13.7 billion years ago, the universe was made of only hydrogen, helium and traces of lithium — byproducts of the Big Bang. Some 300 million years later, the very first stars emerged, creating additional chemical elements throughout the universe. Since then, giant stellar explosions, or supernovas, have given rise to carbon, oxygen, iron and the rest of the 94 naturally occurring elements of the periodic table.

 

Today, stars and planetary bodies bear traces of these elements, having formed from the gas enriched by these supernovas over time. For the past 50 years, scientists have been analyzing stars of various ages, looking to chart the evolution of chemical elements in the universe and to identify the astrophysical phenomena that created them.

 

Now a team of researchers from institutions including MIT has detected the element tellurium for the first time in three ancient stars. The researchers found traces of this brittle, semiconducting alloy — which is very rare on Earth — in stars that are nearly 12 billion years old. The findingsupports the theory that tellurium, along with even heavier elements in the periodic table, likely originated from a very rare type of supernova during a rapid process of nuclear fusion. The researchers published their findings online in Astrophysical Journal Letters. …  (MIT-news)

IBEX vacuum cleaning

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A particle-gobbling probe has snared some alien travelers: tiny particles from interstellar space that, after being born from the ashes of an exploding star, breached a protective bubble blown by the sun and sailed into the jaws of the awaiting spacecraft.

“These are some first observations of interstellar material, really alien matter,” Dave McComas, a principal investigator for NASA’s Interstellar Boundary Explorer spacecraft, or IBEX, said January 31 in a NASA press conference announcing the findings. “This alien interstellar material is really the stuff that stars and planets and people — all of us — are made of,” said McComas, of the Southwest Research Institute in San Antonio. …(ScienceNews)

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Gone, gone

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Using NASA’s Hubble Space Telescope, astronomers have solved a longstanding mystery on the type of star, or so-called progenitor, that caused a supernova in a nearby galaxy. The finding yields new observational data for pinpointing one of several scenarios that could trigger such outbursts.

Based on previous observations from ground-based telescopes, astronomers knew that a kind of supernova called a Type Ia created a remnant named SNR 0509-67.5, which lies 170,000 light-years away in the Large Magellanic Cloud galaxy. The type of system that leads to this kind of supernova explosion has long been a high importance problem with various proposed solutions but no decisive answer. All these solutions involve a white dwarf star that somehow increases in mass to the highest limit. Astronomers failed to find any companion star near the center of the remnant, and this rules out all but one solution, so the only remaining possibility is that this one Type Ia supernova came from a pair of white dwarfs in close orbit. (HubbleSite)

A distant Type-Ia

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These three images taken by NASA’s Hubble Space Telescope reveal the emergence of an exploding star, called a supernova.

Nicknamed SN Primo, the exploding star belongs to a special class called Type Ia supernovae, which are distance markers used for studying dark energy and the expansion rate of the universe. Type Ia supernovae most likely arise when white dwarf stars — the burned-out cores of normal stars — siphon too much material from their companion stars and explode. … (HubbleSite)

White colored home stretch

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  • The Milky Way is redder than most spiral galaxies, but when combined with its blue arms, its overall color is white.
  • Our galaxy is very typical in terms of the type and number of its stars, research shows.
  • The Milky Way’s overall color is about the shade of white halfway between an incandescent light bulb and the standard spectrum white on a TV.

Turns out the Milky Way is aptly named, with the overall color of our galaxy resembling the shade of fine-grained spring snow in early morning light.

Splitting the light into its component wavelengths, however, reveals a redder-than-average color for the Milky Way’s core, and sky-blue spiral arms.

The portrait, pieced together from 1,000 similar galaxies culled from the Sloan Digital Sky Survey, shows the Milky Way as it would appear from perspective of another galaxy, albeit one whose inhabitants have vision similar to humans. …(Discovery)