Scientists have announced the first planet found to be orbiting a brown dwarf. It’s a significant discovery and a fascinating window into the evolution of a type of substellar object we don’t know much about.
A brown dwarf — sometimes referred to as a failed star — is an object of near-Jupiter size, but substantially greater mass. Unlike a normal star, it is not massive enough to fuse hydrogen and does not emit much visible light. Brown dwarfs can fuse deuterium and lithium, but never reached the size required to sustain hydrogen fusion in their cores.
As you might imagine, there are questions regarding when a super-planet (a planet of greater than Jupiter mass) gathers enough material to qualify as a brown dwarf. Because they aren’t particularly luminous, they aren’t all that easy to spot. The researchers in question note: “Our galaxy could also be teeming with brown dwarfs, which cannot sustain hydrogen fusion and thus are very faint.”
Now, here’s the catch: We’ve actually found very large planets orbiting brown dwarfs before. As the researchers note, however:
[The] large mass ratios (q & 0.1) between the host and the companion would suggest that they are formed as binary systems either by the dynamical interaction in unstable molecular clouds (Bate 2009, 2012) or by the turbulent fragmentation of molecular cloud cores (Padoan & Nordlund 2004). This implies that the companions could be considered as substellar objects rather than planets (Chabrier et al. 2014). By contrast, the low mass ratio of this event (q ∼ 0.016), combined with recent reports of the massive disks (& MJ) around young brown dwarfs (Hervey et al. 2012; Andr´e et al. 2012; Palau et al. 2014), suggest that the planetary companion of the event may be formed by planet formation mechanisms.
In other words: In the past, we’ve found planets that appear to have formed around brown dwarfs very differently than how we believe our sun and solar system were created. This planet appears to have been formed in the more normal fashion, suggesting that brown dwarf systems may be able to host planets (or at least a planet) as well.
The chances of such planets hosting life, however, are pretty slim. Brown dwarfs are not thought to be capable of emitting significant amounts of heat, since they contain relatively low amounts of fusable material in the first place. Old brown dwarfs are cool enough to have an atmosphere, though it isn’t one you want to breathe (it can rain iron in the atmosphere of a brown dwarf). Still, a brown dwarf with a planet around it is a surprising find and could tell us more about how planets form, even around exceptionally low-mass, not-quite-stars.
AMD Has No Near-Term Plan For Hybrid Big, Little Cores on Same Silicon
AMD has no plans to build a hybrid CPU with big and little cores any time in the near future, but the company continues to evaluate the concept.
Astronomers Spot Earth-Sized Rogue Planet Wandering the Galaxy
Astronomers have identified more than 4,000 exoplanets orbiting other stars but just a few "rogue planets" wandering the galaxy without a star to call home. A new study claims to have spotted one of these worlds, and it may be a small, rocky world like Earth.
Scientists Find Planet Where It Rains Molten Rock
The ground is rock, the seas are rock, and yes, even the air is rock.
SpaceX Plans Imminent High-Altitude Starship Test
Following a successful static fire test this week, SpaceX CEO Elon Musk has announced on Twitter that the company wants to perform a high-altitude test flight as early as next week.