A vast protostar, spewing a torrent of matter formed from huge dust clouds, could give astronomers the best insight to-date into how our solar system was created. The star-in-waiting, just 300,000 years old and found 450 light years away in the Taurus constellation, is early in its lifecycle: L1527 (aka Roberta J. L1527) has consumed roughly a fifth of the surrounding envelope – the cloud of predominantly hydrogen and heavier molecular dust around it – on its way to reaching the critical temperature at which nuclear fusion begins.
When that happens, the protostar will graduate to full star status, though there’s some time to go – and plenty of measurements – before that transition occurs. Currently, it’s young, broad, but low in mass, with astronomers calculating that though the protostar occupies a volume around seven times that of our own Sun, its mass is only around 19-percent. The 300,000 year figure could even be over-estimating the protostar’s age, based as it is on a constant accretion rate; the team suggests that, using more likely models, it may well be younger.
Spotted by John J. Tobin at the Gemini telescopes in Chile, L1527 has since been remotely observed using various astronomical tools including California’s Combined Array for Research in Millimeter-wave Astronomy (CARMA), and Hawaii’s Submillimeter Array (SMA). Tobin and his team hope to fill in some of the missing knowledge about solar system creation from those observations: until now, a so-called class zero protostar has not been observed.
Class zero is the stage at which interstellar gas collected in clouds becomes unstable for some reason, producing a hot-spot and triggering a chain reaction of atomic ionization through infrared light and heat. A spinning disc forms around the core – thanks to gas clouds entering at angles within the envelope – with some accreting onto it, and the rest being blasted out in jets along the axis, as per the NASA/JPL-Caltech/R.Hurt (SSC) artist’s impression above.
Other matter clusters and is believed to form planets; by measuring the Doppler shift of radio waves from carbon monoxide in the disc surrounding the protostar, the astronomers were able to identify so-called Keplerian rotation. That pattern – rotation speed changing depending on the distance from the protostar core – indicates the disk supports its own movement, and “will mediate the flow of material onto the protostar and allow the planet formation process to begin” Hsin-Fang Chiang of the University of Illinois and the Institute for Astronomy of the University of Hawaii explains.
“In many ways, this system looks much like we think our own Solar System looked when it was very young” Tobin said of the discovery, which has been reported in Nature [subscription required]. Further observation of L1527 is expected to help explain the early life cycle of solar systems.
[via Ars Technica]