Celestia Forums

A very interesting find by Michel Mayor and team: three super-Earth candidates orbiting K2.5 star HD 40307.

http://www.spaceref.com/news/viewpr.html?pid=25660

Here are the stats:

http://exoplanet.eu/star.php?st=HD+40307

The orbital periods are all quite short: 4.31, 9.62, and 20.45 days. Compare this with Mercury's orbital period of about 88 days. Even though the K2.5 star is significantly cooler than the Sun, it's clear that these planets will not lie within the habitable zone.

--Chris

More information on the new planets from oklo.org, my favorite source of information on extrasolar planets:

http://oklo.org/?p=283

(I enjoyed Greg's polite dig at the misleading press release image . . .)

--Chris

In a followup post on oklo.org, Greg Laughlin raises the question of what these planets are: overgrown terrestrials (super-Earths), or iceballs that migrated inwards from the outer system (in a sense, failed gas giants, or "sub-Neptunes").

Hopefully there will at some stage be a discovery of transits of a planet in the sub-10 Earth mass regime.

ajtribick wrote:In a followup post on oklo.org, Greg Laughlin raises the question of what these planets are: overgrown terrestrials (super-Earths), or iceballs that migrated inwards from the outer system (in a sense, failed gas giants, or "sub-Neptunes").

Hopefully there will at some stage be a discovery of transits of a planet in the sub-10 Earth mass regime.

My hunch (and it's nothing more than that) is that it we'll see that happen within the year--I wonder if the Swiss team may already have some transit data for some of their newly found but still unannounced planets. It will be very exciting to get a handle on the nature of these intermediate bodies, especially the ones in the 2-10 Earth mass range which have no analogs in our own solar system.

--Chris

Additional planets are reported around HD 40307, including a habitable planet candidate.

Habitable-zone super-Earth candidate in a six-planet system around the K2.5V star HD 40307
http://arxiv.org/abs/1211.1617

http://spaceref.com/extrasolar-planets- ... -life.html
Note they appear to have used Celestia in their video.