Thursday, December 6, 2012

A Star is Born

The Daily Mail reports on the discovery of a "baby" star:
A ‘baby’ star has been captured just before ‘birth’ by astronomers for the first time - a breakthrough being described as the potential 'holy grail' of stellar evolution.

. . . The infant is just 300,000 years old at most - compared to the 4.6-billion-year age of our Sun and its planets - and is more than 450 light-years from Earth in the constellation Taurus.
John Tobin, a Hubble Fellow student at the National Radio Astronomy Observatory in West Virginia, said: 'It may be even younger, depending on how fast it accumulated mass in the past.'
Currently about one-fifth the mass of the Sun, it is expected to pull in material from its surroundings to eventually match it.
The disk surrounding the young star contains at least enough ‘stuff’ to make seven Jupiters - the largest planet in our solar system.
Tobin, whose discovery is described in Nature, said: 'This very young object has all the elements of a solar system in the making.'
Called L1527 IRS, the young star resides in a stellar nursery known as the Taurus Cloud and is one of the closest examples of the earliest stage of star formation.
The astronomers used the state-of-the-art telescopes to detect both dust and carbon monoxide around the object.

They were the first observers to conclusively show the young star is surrounded by a rotating disk of material and the first to be able to measure the mass of the protostar itself.

By measuring radio waves coming from carbon monoxide in the disk they were able to show the rotation speed changes with the material’s distance from the star in the same fashion the orbital speeds of planets change with distance from the Sun.

Hsin-Fang Chiang, a post-doctoral fellow at Illinois University, said this pattern called Keplerian rotation 'marks one of the first essential steps toward forming planets.'
He said the disk is 'supported by its own rotation, will mediate the flow of material onto the protostar and allow the planet formation process to begin.'
Tobin said: 'This is the youngest protostar found thus far to show that characteristic in a surrounding disk.
'In many ways, this system looks much like we think our own solar system looked when it was very young.'

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