View Full Version : Discussion: Selecting Stars Very Similar to ...

2004-Jan-21, 07:20 PM
SUMMARY: The search for Earthlike planets begins with the search for Sunlike stars. At the top of the list is a reasonably nearby star called 37 Gem; located in the Gemini constellation. Astronomer Maggie Turnbull was asked to make a short list of thirty candidate stars that closely matched our own Sun out of a total list 2,350 stars which are within one hundred light years from us. This short list, including 37 Gem will be used by the Terrestrial Planet Finder mission, which will search for habitable planets by looking for the visible light of oxygen or water in an Earthlike planet - a sure sign of life.

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2004-Jan-21, 09:13 PM
I think its great someone is identifying likely targets for earth like planets around stars similar to the sun. I would like to know hwhere I can get the list of the 30 stars identified out of the larger list. please replay to mickey.schmidt@usafa.af.mil

2004-Jan-22, 12:14 AM
Mickey, try this site:


There's a copy of the HabCat in pdf form.

2004-Jan-22, 01:01 AM
How sun-like are these sun-like stars? Plus or minus 10% in mass and/or luminosity?

Earth-like planets from 0.2 to 0.4 AU from red dwarfs and planets > 1.0 AU from more luminous stars might support life as well. Also moons similar to the Jovian Gallilean moons are worth considering. Quite a few Jupiter scale planets at distances of from 0.7 to 5.0 AUs have already been located in other stellar systems. Our search must not be allowed to be too narrow.

2004-Jan-22, 02:12 AM
Those Sun-like Star is too huge, even with the best telescope on Earth, we still cant see anything...its too tiny (Wee)... sometime it looks like a Sunspot (Sun-Like) or something... :lol: I am talking about the planet not the star.

Maggie Turnbull
2004-Jan-24, 01:22 AM
The final list of ~30-ish stars won't be available for some time yet, but I do have a list of the best ~140 candidates. The list includes 37 Gem, 18 Sco, and 51 Peg. The stars are include a spread of spectral types (masses) but they all have hydrogen-burning lifetimes of at least 2-3 billion years, are non-variable, have high metal content (an indicator of whether planets could have formed) and do not have any close companion stars. However, the engineers need to take this list of 140 and figure out whether any single instrument will be capable of observing all of them (it won't). Then we will narrow and refine the list according to what a single instrument design can accomodate, and end up with the 30 "best" stars according to both astronomers and engineers. But all of these stars are excellent candidates, and 37 Gem is just one example (which happens to be visible with binoculars, at sixth magnitude).

Maggie Turnbull

2004-Jan-24, 03:50 AM
Fantastic - I find this area of astronomy to be fascinating. This kind of research, IMHO, is spearheading modern astronomy and I'm beginning to wish I'd studied more at College and could be on the team!!!!

2004-Jan-24, 04:02 AM
Tell us a bit more about 37-Gem, what specifically wwill the researchers be looking for?

2004-Jan-24, 04:14 AM
37-gem? is that the Gemini constellation?

2004-Jan-31, 02:02 AM
Hello everyone, I'm sort-of new here but I do have a question. I've noticed everone saying that everthing is moving AWAY from each other Galaxies etc.. Why then is the Milky Way & Amdromeda Galaxy going to collide? :-(


2004-Jan-31, 08:02 AM
I'm an Alpha Centauri fan...probably harks back to my childhood when I was glued to the TV set watching "Lost In Space" every night!!!

Just wondering, this star being our closest neighbour and all, and a G2 just like our pal Sol...surely this would be at the top of the list? I know Hubble looked at Alpha Centauri A back in '97 or so...but for the life of me, I can't find zilch about any results?? Have we found extra-solar planets there at all??? Have we even LOOKED????

Who knows, maybe we got an alien civilization right on our doorstep!??

2004-Jan-31, 08:09 AM
I've noticed everone saying that everthing is moving AWAY from each other Galaxies etc.. Why then is the Milky Way & Andromeda Galaxy going to collide?

The gravitational attraction overrides the spacetime expansion.

2004-Jan-31, 03:40 PM
Originally posted by Guest@Jan 31 2004, 02:02 AM
Hello everyone, I'm sort-of new here but I do have a question. I've noticed everone saying that everthing is moving AWAY from each other Galaxies etc.. Why then is the Milky Way & Amdromeda Galaxy going to collide? :-(

The expansion of the universe's works only on the largest scale.
Clusters of galaxies, such as the local group with the Milky Way, Andromeda, and 30-ish smaller galaxies, interact on their own.

Just a note. It is actually soace that is expanding and in doing so dragging the galaxies along for the ride. It is not the galaxies that are blowing outward like pieces of shrapnel (sp) in an explosion. Think of rising dough in raisin bread as expanding (space) and in doing so separating the raisins (galaxies). The galaxies/raisins separate from each other but do not get larger themselves.
Astronomer Mike Best :)

2004-Feb-01, 01:34 AM
Hi Mike! I love to see astronomers & scientists in this forum!!

I have a question...Is spacetime expanding between, say, the Earth & the Moon? Yes I know it would be INFINITESIMALLY, to the point of HARDLY AT ALL...and the gravitational link between us would cancel out any hope of measuring that expansion. BUT, is there expansion happening there just the same?? Just curious...

2004-Feb-02, 03:02 AM

why is it that we always search for human like creatures in universe, or even search for life forming conditions similar to earth. isn't it quite possilble that the other forms have developed on really different lines?

2004-Feb-02, 06:58 AM
What, like octopus-like aliens?? :P

I know, biologists say extraterrestrial life would be vastly different than life on Earth...that human beings are a one-off kinda thing, specific to our planet.

But...who knows? Life itself is unlikely. Maybe there are forces that "push" life into existence? Maybe there are "moulds", universally speaking...so that maybe the "humanoid" type form isn't so uncommon??

Who knows? But just looking at Planet Earth, we see every possible form & shape & colour of life. It's like one big zoo. I'm sure the rest of the cosmos reflects this too.

Back to my original question...Can anyone point me to any update information on the Alpha Centauri system? Why such lacking on the 'net when it's our closest neighbour, and not only that, Alpha A is very similar to our Sun? ...hmm, more conspiracies...?

2004-Feb-03, 04:18 AM
LOL Faulkner - have you been watching Babylon 5 again? :)

Seriously, it's a fair point... I've often wondered if there was any chance of life in the Alpha Centauri system...