with 8 times Jupiter’s mass if it’s the age of the star cluster, 5 million years.
But this is not confirmed! For example, it could be a low mass star that happens to be near the other star along our line-of-sight — in other words, it’s in the background. The best way to see if that’s true is to wait a year or two and take more images. If the object moves against the background stars along with the brighter star, then it must be physically associated with the star, and therefore it’s a planet. This is how we confirmed the first image of an exoplanet back in 2005 — but that was orbiting a brown dwarf, a star very different than the Sun.
If confirmed, this one is pretty important, because the parent star is much like our own Sun. The most interesting thing about this is the distance of the purported planet from the star: 50 billion kilometers! That’s 11 times the distance Neptune is from the Sun. And that’s a lower limit; it might be farther. That makes me very suspicious: we don’t know of any way to form planets that far from their parent stars.
Stars and planets form from rotating disks of gas and dust. The stuff collects in the middle to form the star, and the stuff farther out forms the planets — we have seen many examples of this in the sky. The disks we see around new stars are big, sure, but by the time you get 50 billion km out they are very thin, and there’s just not enough material out there to form a planet, let alone one with 8 times the mass of Jupiter.
In this case, the most likely explanations for this image are that 1) this isn’t a planet, but a background star, or 2) it formed closer in and was ejected by an encounter with another planet, moving it way the heck out from the star. (1) is a bummer, and is unlikely just due to statistics; it’s isn’t high odds to see an object like this by coincidence so near another star. (2) seems unlikely to me as well; it’s hard to toss around a planet that mass unless an even more massive planet was involved. I hope this star is a target for searches for more planets, just to get more information on this scenario.
To their credit, the astronomers involved are also clear about this in their paper announcing the discovery. This is a carefully done observations, and they are appropriately careful in their announcement.
But if it’s true… WOW. This would be the second planet ever seen directly in an image, and the first to orbit a star like the Sun. The implications would profound. It would be direct evidence of planets orbiting other stars at great distances. It would mean there could be another planet in our own solar system (unlikely, but I’ve written about that before). And it would mean that it’s possible to use this method of near-infrared mapping to actually get pictures of more planets! Seeing one might be a fluke, seeing two means there are more to find.
The next clear night, do yourself a favor: go outside. Look up. See all those stars? Whether or not this particular planet pans out, we still know that a large fraction of those stars — 10%? 20? — may have planets. And some fraction of those may have planets like Earth orbiting them. We really weren’t sure about this even 15 years ago, and now we’re able to not only start plugging numbers into the equations, but we can actually take pictures of some of these objects.
My oh my. How I do love science.
Links to this Post
- Discovery of a Planet around a Sun like Star? « Harmonic Guru | September 15, 2008
- Primeira foto de um planeta em outro sistema solar? « idealismo de buteco | September 15, 2008
- Planet imaged around a sunlike star?! - The Michael Jackson Internet Fan Club | September 15, 2008
- Discovery Space: Space Disco | September 15, 2008
- Das erste Bild eines extrasolaren Planeten? at AntiTerra | September 15, 2008
- Stochastic Scribbles » Blog Archive » Image of planet around Sun-like star? | September 15, 2008
- For Dads » Blog Archive » Astronomy Search Engine Results | September 16, 2008
- oranchak.com » Blog Archive » links for 2008-09-16 | September 16, 2008
- Exoplanet imaged around Sun-like star « The