* Astronomy

Blobrana · L

RE: VY Canis Majoris

Blobrana · L

HD Star Size Comparison Video - How big we really are!

Click to Play | View Details

Blobrana · L

VY Canis Majoris compared to earth and our sun

Click to Play | View Details

The size of VY Canis Majoris

Click to Play | View Details

Blobrana · L

The death throes of the biggest star known to science have been observed by Europe's new space telescope, Herschel.
The observatory, launched in May, has subjected VY Canis Majoris, to a detailed spectroscopic analysis.
It has allowed Herschel to identify the different types of molecules and atoms that swirl away from the star which is 30-40 times as massive as our Sun.

Read more

Blobrana · L

VY Canis Major

Blobrana · L

RE: VY Canis Majoris

Blobrana · L

University of Arizona astronomers who are probing the oxygen-rich environment around a supergiant star with one of the world's most sensitive radio telescopes have discovered a score of molecules that include compounds needed for life.

"I don't think anyone would have predicted that VY Canis Majoris is a molecular factory. It was really unexpected. Everyone thought that the interesting chemistry in gas clouds around old stars was happening in envelopes around nearer, carbon-rich stars. But when we started looking closely for the first time at an oxygen-rich object, we began finding all these interesting things that weren't supposed to be there" - Arizona Radio Observatory (ARO) Director Lucy Ziurys, UA professor of astronomy and of chemistry.

VY Canis Majoris, one of the most luminous infrared objects in the sky, is an old star about 5,000 light years away. It's a half million times more luminous than the sun, but glows mostly in the infrared because it's a cool star. It truly is "supergiant" -- 25 times as massive as the sun and so huge that it would fill the orbit of Jupiter. But the star is losing mass so fast that in a million years -- an astronomical eyeblink -- it will be gone. The star already has blown away a large part of its atmosphere, creating its surrounding envelope that contains about twice as much oxygen as carbon.
Ziurys and her colleagues are not yet halfway through their survey of VY Canis Majoris, but they've already published in the journal, Nature (June 28 issue), about their observations of a score of chemical compounds. These include some molecules that astronomers have never detected around stars and are needed for life.

Source

Read more

Jets of molecules, indicated by red and blue arrows, flow from the supergiant star VY Canis Majoris photographed by the Hubble Space Telescope. The blue arrow (lower right) shows the slight deviation of the squirt flow from the direction towards us. The curved nebulous tail (CNT) and red arrow (upper right) show the fan of material flowing away from us and to the side. The white arrows and transparent circle show the general spherical flow of matter outward. (Illustration: UA Steward Observatory)

Blobrana · L

One of the largest and most luminous stars in our galaxy is a surprisingly prolific building site for complex molecules important to life on Earth, new measurements reveal.
The discovery furthers an ongoing shift in astronomer's perceptions of where such molecules can form, and where to set the starting line for the chain of events that leads from raw atoms to true biology.

"Where we thought molecules could never form, we're finding them. Where we thought molecules could never survive, they're surviving" - Lucy Ziurys, an astronomer at the University of Arizona in Tucson, US.

Using the 10-metre radio dish atop Mount Graham in Arizona, Ziurys and her team searched the extended envelope of gas around VY Canis Majoris, a red hypergiant star estimated to be 25 times the Sun's mass and nearly half a million times the Sun's brightness.
There they found the telltale radio emissions of various compounds, including hydrogen cyanide (HCN), silicon monoxide (SiO), sodium chloride (NaCl) and a molecule, PN, in which a phosphorus atom and a nitrogen atom are bound together.
Even simple phosphorus-bearing molecules such as PN are of interest to astrobiologists because phosphorus is relatively rare in the universe yet it is necessary for constructing both DNA and RNA molecules, as well as ATP, the key molecule in cellular metabolism.

Read more

Blobrana · L

Title: A VLBI polarisation study of SiO masers towards VY CMa
Authors: L.L. Richter, A.J. Kemball, J.L. Jonas

Maser emission from the SiO molecule has been widely observed in the near-circumstellar envelopes of late-type, evolved stars. VLBI images can resolve individual SiO maser spots, providing information about the kinematics and magnetic field in the extended atmospheres of these stars. This poster presents full polarisation images of several SiO maser lines towards the supergiant star VY CMa. VY CMa is a particularly strong SiO maser source and allows observations of a wide range of maser transitions. We discuss implications of these observations for VY CMa morphology, polarisation, and pumping models.

Read more (63kb, PDF)

Blobrana · L

Using NASA's Hubble Space Telescope and the W.M. Keck Observatory, Kameula, Hawaii, astronomers have learned that the gaseous outflow from one of the brightest super-sized stars in the sky is more complex than originally thought.
The outbursts are from VY Canis Majoris, a red supergiant star that is also classified as a hypergiant because of its very high luminosity. The eruptions have formed loops, arcs, and knots of material moving at various speeds and in many different directions. The star has had many outbursts over the past 1,000 years as it nears the end of its life.

Read more

-- Edited by Blobrana at 00:23, 2007-01-09