Stanford University | 2015 Nov 18
The newly found 'protoplanet' is 450 light years away, but observing how it collects matter and grows could answer some of the biggest questions concerning how our solar system formed.
[img3="Artist's illustration shows how planets could form in a transition disk around a star similar to LkCa 15. By isolating the hydrogen-alpha light from the vicinity of that star, astronomers at Stanford and the University of Arizona were able to identify a planet in the early stages of formation. (Credit: NASA/JPL-Caltech/T. Pyle (SSC))"]http://www.spitzer.caltech.edu/uploaded ... 012_Sm.jpg[/img3][hr][/hr]Since prehistory, humans have speculated about how the planets in our solar system were formed. Today, astronomers announce evidence of an exoplanet being born that could move us one step closer to understanding the process of planet formation around other stars.
The alien planet, called LkCa 15 b, orbits a star 450 light years away and appears to be on its way to growing into a world similar to Jupiter.
"This is the first incontrovertible detection of a planet still in the process of forming – a so-called 'protoplanet'," said Kate Follette ...
The planet is forming in a transition disk, a doughnut-like ring of dust and rocky debris orbiting its parent star, LkCa 15. The central clearings within transition disks are believed to be created by the formation of planets, which sweep up dust and gas from the disk as they orbit the star. Astronomers have long speculated that investigating these gaps could lead to the discovery of protoplanets, but getting a good look at these infant worlds has been challenging.
Follette and her colleagues took a new tack, and designed an imaging instrument to look for a characteristic planet formation signature. The process by which a planet grows from a rocky or icy core to a full-fledged gas giant is incredibly energetic. As hydrogen gas falls from the disk onto the core of the protoplanet, it heats up and glows like a fluorescent light bulb, emitting a characteristic wavelength of visible light called "Hydrogen-alpha," or H-alpha. ...
Accreting protoplanets in the LkCa 15 transition disk - S. Sallum et al
- Nature 527(7578):342 (19 Nov 2015) DOI: 10.1038/nature15761