CoRoT Results

This thread will be dedicated to the CoRoT (Convection, Rotation, and planetary Transits) spacecraft, the first spacecraft launch with the ability to seriously look for planets, (as opposed to Hubble which found the SWEEPS candidates, but Hubble isn't quite the most reliable tool for finding exoplanets). A similar thread will be made for Kepler in the future.

In May of 2007, the first planet, CoRoT-Exo-1b was announced, and in December of 2007, the second planet was announced. In May of 2008, three more objects were announced.

So as far as planets go, we have these five objects:

Star	Planet	Mass	P (d)	Radius
CoRoT-Exo-1	b	1.03 J	1.5089557 d	1.49 J
CoRoT-Exo-2	b	3.31 J	1.7429964 d	0.83 J
CoRoT-Exo-3	b	20.2 J	4.25 d	1.17 J
CoRoT-Exo-4	b	1.1 J	9.20205 d	1.2 J
CoRoT-Exo-5	b	0.86 J	4 d	? J

I don't get why Corot team does never publish orbital separations in Astronomical Units?!

Updated data for Corot-Exo-1 and 2:

http://exoplanet.eu/star.php?st=CoRoT-Exo-1
http://exoplanet.eu/star.php?st=CoRoT-Exo-2

Added orbital separations and host stars.
Both planetary companions show zero eccentricity.

Seems to have also been an update for Corot-Exo-3 and 4, though the host star coordinates are still absent.

Only 1 and 2 show actual host star. At the moment.

Additionally, they added the metallicity [Fe/H] of CoRoT-Exo-1 and 2, and updated the radius of CoRoT-Exo-2 b.
The update for CoRoT-Exo-3 is the age, now given at 0.85 Gyr.

CoRoT-Exo-3 b was updated. The mass is just a bit higher, now at 21.6 Jupiters, but the radius is also lager, 0.97 Jupiter radii. This brought the density down some.

The paper for CoRoT-Exo-4 b is now available.

Transiting exoplanets from the CoRoT space mission V. CoRoT-Exo-4b: Stellar and planetary parameters
http://arxiv.org/abs/0807.3739

Abstract wrote:

The CoRoT satellite has announced its fourth transiting planet (Aigrain et al. 2008) with space photometry. We describe and analyse complementary observations of this system performed to establish the planetary nature of the transiting body and to estimate the fundamental parameters of the planet and its parent star. We have analysed high precision radial-velocity data, ground-based photometry, and high signal-to-noise ratio spectroscopy. The parent star CoRoT-Exo-4 (2MASS 06484671-0040219) is a late F-type star of mass of 1.16 Msun and radius of 1.17 Rsun. The planet has a circular orbit with a period of 9.20205d. The planet radius is 1.19 Rjup and the mass is 0.72 Mjup. It is a gas-giant planet with a ''normal'' internal structure of mainly H and He. CoRoT-Exo-4b has the second longest period of the known transiting planets. It is an important discovery since it occupies an empty area in the mass-period diagram of transiting exoplanets.

Not a bright F0 star, but a Solar-like one. Radius and mass were similar to those of Sun, indeed

It seems the planet's orbit and the rotation period of the star are synchronized.
http://www.space.com/scienceastronomy/080724-new-exoplanet.html

Space.com wrote:

By tracking the time between transits, a team of scientists
led by the French space agency CNES measured how long the planet takes to
revolve around its star, and found that it is the same period of time its star,
which is slightly larger than our sun, takes to rotate 360 degrees. They were
able to derive the star's period of rotation by monitoring dark spots on its
surface that rotated in and out of view.

Earlier, there were rumors that CoRoT had found a 1.7 Earth-radius transiting object. Here's the light curve for that. The first image is the normal light curve, the second image is zoomed in on it.

The CoRoT website wrote:

Good news also on the side of finding small planets.

CoRoT has picked up signals as small as 5 parts in ten thousand. If it
is the transit, the planet's radius would be 1.7 times the radius of
the Earth.

(ref)

Sirius_Alpha wrote:

The paper for CoRoT-Exo-4 b is now available.

Transiting exoplanets from the CoRoT space mission V. CoRoT-Exo-4b: Stellar and planetary parameters
http://arxiv.org/abs/0807.3739

There are two papers about this object, the first is "Transiting exoplanets from the CoRoT space mission IV: CoRoT-Exo-4b: A transiting planet in a 9.2 day synchronous orbit"

Yes, indeed.

I like how each CoRoT planet is getting enough attention has they have been. For example, CoRoT-Exo-2 had two papers on it, as does CoRoT-Exo-4. With papers with this degree of specificity, it doesn't leave the planets seemingly void of information. We actually know something interesting about the planets, more than just their orbital and physical parameters. As opposed to the most recent 10 WASP planets... which seem little more than vague numbers for which we still waiting on papers for.

http://exoplanet.eu/papers/Deleuil-CoRoT3.pdf (pdf)

(updated figures) CoRoT-Exo-5 b has a period of 4.03 days, a mass of 0.67 Jupiters, and a radius of 1.2 Jupiter radii.

Ohh this is all interesting and quite thoroughly done. The lack of au data makes it confusing however. I have to actually try and fail to figure out how far they really are from the star.


Any more updates on the potential 1.7 earth radius one or was it alot larger?

Darkness Nova wrote:

Any more updates on the potential 1.7 earth radius one or was it alot larger?

I e-mailed someone, I forgot who now, a few months back and haven't got a response about the 1.7 Earth-radius planet. But no updates have been provided.

Darkness Nova wrote:

Ohh this is all interesting and quite thoroughly done. The lack of au data makes it confusing however. I have to actually try and fail to figure out how far they really are from the star.

Here's the updated table with AU values now, provided by various papers over the past year or so. Note that the semi-major axis of CoRoT-Exo-5 b hasn't been given in any papers yet. But if you assume CoRoT-Exo-5 has one solar mass (I'm unsure where that figure comes from...), you can find it by plugging stuff in,

keeping all of your units at base units.

where :
a is the semi-major axis (metres)
Mu is equal to GM, which is the gravitational constant multiplied by the mass of the star (kilograms).



Doing the math, I get 0.05295 AU. Anyway here's that table.

Star	Planet	Mass	P (d)	Radius	a (AU)
CoRoT-Exo-1	b	1.03 J	1.5089557 d	1.49 J	0.0254
CoRoT-Exo-2	b	3.31 J	1.7429964 d	0.83 J	0.0281
CoRoT-Exo-3	b	20.2 J	4.25 d	0.97 J	0.052
CoRoT-Exo-4	b	1.1 J	9.20205 d	1.2 J	0.09
CoRoT-Exo-5	b	0.67 J	4.03 d	1.2 J	?

First CoRoT International Symposium
http://www.symposiumcorot2009.fr/

February 2nd - 5th 2009

Aww. So late

Actually the relevant mass in the orbital radius equation is the total mass of the star and planet added together:

a³ = G(M+m)T²/(4π²)

Admittedly, this doesn't make much of a difference if m << M.

CoRoT-Exo-4 b is indeed not exactly synchronized with it's parent star.
http://www.aanda.org/index.php?option=article&access=standard&Itemid=129&url=/articles/aa/abs/2008/35/aa10246-08/aa10246-08.html

Abstract wrote:

We determine the periods of the planetary orbit and star's rotation of 9.20205 $\pm$ 0.00037 and 8.87 $\pm$ 1.12 days respectively, which is consistent with this being a synchronised system.

Sirius_Alpha wrote:

CoRoT-Exo-4 b is indeed not exactly synchronized with it's parent star.

True the determination of the planetary period and the determination of the star's rotation period do not yield the exact same value, but the synchronised case does lie within the uncertainties. That is why they say it is consistent with being synchronised.

Oh... yeah you're right... apparently I misread that pretty badly. I saw "inconsistent" instead of "consistent".

CoRoT-Exo-3 updated. According to the Extrasolar Planets Encyclopaedia:

Value	Previous	Updated
Distance	-	680 ± 160 pc
Mass	1.27 M_sol	1.37 M_sol
Age	0.85 Gyr	2 Gyr
Temp	6630 K	6740 K
Star Radius	1.305 R_sol	1.56 R_sol
[Fe/H]	-0.05	-0.02
Planet Radius____	0.97 R_Jup____	1.008 R_Jup

And thus the density comes down again, from 32.46 g/cm^3 to 28.93 g/cm^3 (based on density formula).

Decrease in the planet/star radius ratio which is interesting, more than compensated for by the change in the radius estimation for the star.

Uncertainties in stellar radii are one of the major sources of uncertainties in exoplanetary radii.

CoRoT-Exo-3 paper is out now.
http://exoplanet.eu/papers/CoRoT-3.pdf (pdf)