Earth-sized planet found around Alpha Centauri B

reply to post by Soylent Green Is People


Oh ok, I understand now. Sorry about that Flexy123

check my prediction from October 2010

the 3 ongoing searches of alpha centauri for planets have come up blank so far but the search isnt finished. Centauri B looks a better bet if we're hoping for planets.

www.abovetopsecret.com...

this planet was found around centauri B

i think there must be more planets around this star but it will take a long time to find them

reply to post by yeti101


Agreed, their probably are more planets around Centauri B. Hopefully it won't take to much longer for them to find them all now

Originally posted by Stari
reply to post by yeti101

 

Agreed, their probably are more planets around Centauri B. Hopefully it won't take to much longer for them to find them all now

The problem is that using the method used to find this planet (the Doppler Spectroscopy/Radial Velocity method), it is easier to find planets orbiting close to a star, but more difficult to find planets orbiting farther out from that star.

Doppler spectroscopy detects the minute wobble in a star caused by the gravitational tug of an orbiting planet. Generally, the closer the orbit, the larger the wobble. Planets farther out cause a more minute wobble, and are thus harder to detect.

There is also the "Transit Method" for detecting extrasolar planets. That method looks for a planet moving in front of a star, and thus causing the star to dim ever-so-slightly. This method requires that the planet actually DOES move in front of its star as seen from our viewpoint on Earth

I'm not sure if the transit method could be used for Alpha Centauri B, because I don't know it the planets are lined up in such a way that they DO pass between its star and Earth.

Even if they do, the transit method again works best for planets orbiting VERY close to a star (therefore, maybe very hot), because scientists using the transit method usually like to confirm a planet's existence by watching it pass in front of the star several times -- and passing in front of the star several times for a planet orbiting farther out from its star may take years to confirm...

...For example, if some aliens from another star system were using the transit method to detect earth, they would only see it pass in front of our Sun once per year.

Using the transit method, a scientist may "think" a planet might exist based on only one transit (one planetary pass between the star and earth), but it takes at least three transits to get better confirmation of the planets existence -- i.e., the time span between multiple transits would be the same, giving some confirmation. Again, using the example of some aliens trying to detect earth with the transit method, it would take just over two years to detect three transits.

reply to post by Stari


need a space based telescope to detect earth size planets further out in the HZ for a stars as close alpha centauri.

There's a couple of proposed missions that would get the job done. remains to be seen if they get the funding