View Full Version : Next Up, the COROT Space Telescope

2006-Dec-20, 10:14 PM
Step aside Hubble, Chandra, Spitzer, there's a new space telescope ready for launch. On December 27, 2006, the European Space Agency is planning to launch its planet hunting, starquake finding COROT satellite. ...

Read the full blog entry (http://www.universetoday.com/2006/12/20/next-up-the-corot-space-telescope/)

2006-Dec-20, 11:16 PM
I assume results could be quite impressive in only five or six months.

2006-Dec-21, 01:07 PM
If COROT were using the Doppler effect to detect variations in the light color from a star, then it would be easiest to detect hot Jupiters, but if it uses variations in the brightness of the star as a planet transits the face of that star, then, wouldn't it be easiest to detect cold Jupiters, which are (ever so slightly) closer to us, and would hence create a larger silhouette? Even if one discounts the (ever so) slight apparent increase in size, it wouldn't be any easier to detect a hot Jupiter vs. a cold one, no?

2006-Dec-21, 01:39 PM
wouldn't it be easiest to detect cold Jupiters

Hi Neo. welcome to the BAUT forum.

My Understanding is that COROT is designed to detect small variations in a star's luminosity, not the star's slight redshift/blueshift from being tugged by a smaller companion. Even so, COROT will have an easier time detecting Hot Jupiters as compared to cold ones because:

- Being closer to the star, the closer planet's orbital plane can be less perfectly aligned and still result in transits.
- Being closer to the star, the closer planet will transit the star much more often

(The point of these two points is that our chances of detecting them at all increases).

Also concerning your point about the more remote planet giving us a larger silhouette, even assuming that the Hot Jupiter doesn't get puffed up by the heat, and calling the two hypothetical planets the same size the difference in distance is very small. For a star 100 parsecs away, the distance to the star is about 20 million AU. When transiting, the Cold Jupiter will be between one and twenty AU closer than the star. This results in at most a difference of one part per million difference in the depth of the eclipse.

2006-Dec-21, 03:34 PM
I wonder if it can said that hot Jupiter's are larger because they are hot. Hmmmm... I wonder how much larger Jupiter would appear if it were hot?