Comments on: Kepler Finds Two Planets Transiting the Same Star

By: jg

jg — Tue, 31 Aug 2010 19:27:08 +0000

I’ve been trying to put together a presentation on exoplanets and the subject keeps moving faster than I can keep up. From what I read, the large, closely orbiting hot jupiters are thought to have migrated inward from Jupiter-to-Neptune orbits. This migration would disturb and probably destroy any earthlike planets. So, I’m very eager to see earth-size planets in earth-like orbits where there is also a hot jupiter, as that would turn over the understanding of how these large planets got where there are and thus increase the chance of finding earthlike planets.

By: Eric Lund

Eric Lund — Tue, 31 Aug 2010 16:12:48 +0000

My intuition tells me that our current methods for detecting exoplanets are biased in favor of close-in planets. Our main methods are by detecting the gravitational pull (proportional to 1/r^2 where r is the distance from the star to the planet’s orbit) or by detecting a transit (geometry favors close-in planets as they are more likely and more frequently aligned). I know of only one system that has been detected by direct imaging, and that is the very nearby Fomalhaut system, where we can resolve the angular separation between the star and its planets in Neptune-like orbits. It’s also obvious that all three methods favor big planets, which are brighter, more massive, and more likely to be observed transiting.

By: Ray Ingles

Ray Ingles — Tue, 31 Aug 2010 15:53:20 +0000

Would it be possible to assert that a small (“Class M” if you will) planet close enough to a certain size star is more likely to have life, and that large gaseous Jovian planets swooping around in the inner regions of a solar system would reduce the likelihood of that?

Yes, mostly. At least, life based on the kind of chemistry our life uses. We need liquid water, which puts restrictions on temperature – not too hot, not too cold – the “Goldilocks zone”.

It’s generally assumed that wild swings in temperature would be problematic for getting life started, too – so eccentric orbits are presumed to be less hospitable. And big Jovians close to the star can destabilize smaller planets, which would tend to kick them out of the “Goldilocks zone”.

Of course, these assumptions may be too restrictive. There may be “life as we don’t know it.” But until we find some, we won’t know about it. 🙂