Extra Solar Planets Directly Imaged !

[Stu Ward]

I found this absolutely fascinating

http://www.universetoday.com/81640/f...ed/#more-81640


Stu

[mswhin63 (Malcolm)]

quite impressive indeed.

[Osirisra (Ken)]

Awesome stuff!

[ngcles]

Hi Stu & All,

A very impressive observational feat -- well done to the team. Extremely interesting.

Very interesting star exhibiting peculiar spectra that is probably related to its youth (about 40 million years old). The system (of planets) surrounding bears some similarity to our own solar-system (in orbital resonances etc), though the masses of the planets are quite large compared to our system (all four are estimated to be 5-10 Jupiter masses) and they are much further out.

Will be interesting to see if any terrestrial-sized objects can be detected in the coming years. They will be difficult to detect given the system is essentially face on and there will be no transit events to detect. Given the mass of the star (~1.5 solar masses) it will probably settle finally onto the main sequence at about F4-5 with a surface temp about 7450 deg K -- somewhat like neighbouring Procyon (Alpha Canis Minoris) and be about 5x more luminous than our own Sun.

This will result in a total main sequence life-time of 2.73 billion years and it would be a full-blown red-giant at about 3.1 billion years.

If there were (in the future) a terrestrial planet of sufficient mass and type etc etc somewhere near the habitable zone and life did get started there, it would need to develop much, much faster than it did here to even get to the point of being multi-cellular life before the habitable zone moves outward (and away) enough to doom it. There would be no way known that life of any type would be presently be on such a terrestrial planet that would be much too hot and probably still undergoing accretion.

I'd think that in the future, this star might possibly be a life-host (simple life) if there is a terrestrial planet at the right spot with the right conditions etc etc. Multi-cellular life (pond-scum etc) (assuming everything that could be going for it is going in its favour) is a remote possibility.

I'd posit that the development of advanced life, let alone intelligent life would be an extreme long-shot if not completely hopeless (mainly because of the brevity of the time-frame). Larger stars have more distant but slightly wider habitable zones (than our Sun for example) but they move outward much more quickly as the star evolves (and brightens) more rapidly than the Sun does/will. The maximum time a planet would be in the habitable zone (as that zone creeps outward) would be 1-1.5-odd billion years. By comparison, it took 700 million years minimum for single-celled creatures to appear on Earth (from the fossil record) and a further 3 billion years after than for single-celled creatures here to become multi-cellular, then another 400-odd million years before there were advanced plants and animal life.



Best,

Les D

[rogerg (Roger)]

It is an amazing time we live in where these observations and discoveries are being made so quickly and relatively frequently. It's really quite amazing.

I'm fairly sure there's been a few direct imaged exoplanets now, am I wrong? I think this was the first (again, could be wrong):
http://en.wikipedia.org/wiki/Fomalhaut_b

I remember when I first heard of one being imaged directly I hapenned to talk to my uncle a day later who is also interested in astronomy and we were both astonished at how such an event had hapenned now, not in another 10-20 years. Sure you look at the methods they're using now in hind sight and go "well yeah, I guess all it takes is money and time" but still, not something I expected for a few more years yet.

The next "wow" will be when they esolve detail on the planets, where the planets are more than say 10 pixels across. That will be astonishing.

Roger.

PS. prob should have this in the science sub-forum.

[CraigS]

Here ya go Les;

This was published in September .. a mathematical analysis:

First Habitable Exoplanet Could Be Discovered by May 2011

His calculations predict a 50 percent probability that the first habitable exoplanet will be discovered in May 2011, a 66 percent chance by the end of 2013 and 75 percent chance by 2020.
..
Well, more or less. “There is some wiggle room,”
…
Arbesman and Laughlin admit their habitability metric is a little optimistic and their analysis leaves out factors like the march of technology. “It’s not a scientific result, it’s not a discovery,” Laughlin said. “It’s just something to spark discussion, to point out an interesting trend.”

And if they’re wrong, he adds, we’ll know soon enough.

For all the optimists out there …. a model which makes a prediction !

Cheers