Eclipse and transit of HD 80606b

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Eclipse and transit of HD 80606b

Post by Lazarus on 27th January 2009, 6:13 pm

systemic


Last edited by Lazarus on 26th February 2009, 4:35 pm; edited 4 times in total

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Re: Eclipse and transit of HD 80606b

Post by exoplanet on 27th January 2009, 8:40 pm

You can see part of the story already here:

http://www.astronomy.com/asy/default.aspx?c=a&id=7870

As I recall, Greg mentioned a Nature article in the making on HD80606b.

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Re: Eclipse and transit of HD 80606b

Post by Sirius_Alpha on 27th January 2009, 10:08 pm

Hopefully this means that we'll start getting some real information on this thing (a paper?) soon. Soon as in near to now, not Astronomer-Soon.

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Re: Eclipse and transit of HD 80606b

Post by exoplanet on 28th January 2009, 2:28 pm

For those who have access, it has been published in Nature today:

http://www.nature.com/nature/journal/v457/n7229/full/nature07649.html

There is also a feature at Space.com with images.

Enjoy.

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Re: Eclipse and transit of HD 80606b

Post by NuclearVacuum on 29th January 2009, 10:34 am

This is for real!? I just thought that this was a campaign for the year of Astronomy? HD 80606 is a transiting planet?

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Re: Eclipse and transit of HD 80606b

Post by exoplanet on 29th January 2009, 12:36 pm

Secondary eclipse is when the planet passes *behind* the star as seen from Earth. No one knows yet if HD80606b is transiting its host star. A campaign is being setup to observe the system around February 14th, when it is predicted that the next transit may happen. Keep your fingers crossed Smile

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Re: Eclipse and transit of HD 80606b

Post by Edasich on 29th January 2009, 5:01 pm

That would be the longest period transiting planet so far.

And the most eccentric too (in every sense...) Laughing

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Re: Eclipse and transit of HD 80606b

Post by Sirius_Alpha on 29th January 2009, 5:21 pm

Has anyone seen that video on the new systemic post showing the planet as it swings past the star?
Here's the oklo post. http://oklo.org/?p=313
And here's the movie. Link

Can anyone explain this movie to me? I get that it's the planet during a pass of its star, but I'm not sure what the viewing angle is, what is determining its change, and such.

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Re: Eclipse and transit of HD 80606b

Post by Lazarus on 29th January 2009, 5:31 pm

Judging by the description, the vantage point is a test mass in orbit around HD 80606b. The trajectory is thus affected by the gravity of both the planet and the star, which leads to the complicated relative motion.

As said upthread, this is the secondary eclipse that has been detected. There is no guarantee that the transit will occur - for starters, because of the orientation of the orbit, the planet is located much closer to the star when it is eclipsed than it is when it would be in transit, so the probability of the transit is less than the probability of an eclipse, assuming random orientation. (The observation of the eclipse increases the probability of transit, but does not guarantee it)

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Re: Eclipse and transit of HD 80606b

Post by Lazarus on 31st January 2009, 12:11 pm

To expand on my previous post, the relevant probabilities are:

Assuming random orientation of the orbit:
p(transit)=1.0%
p(eclipse)=14%

Given that the eclipse occurs:
p(transit)=7.2%

So I'm not holding my breath...

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Re: Eclipse and transit of HD 80606b

Post by Lazarus on 12th February 2009, 7:41 pm

Greg Laughlin's going to be posting updates on the transit campaign at this systemic post.

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Re: Eclipse and transit of HD 80606b

Post by Sirius_Alpha on 14th February 2009, 9:24 am

Preliminary still, but it seems that no transit was observed.

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Re: Eclipse and transit of HD 80606b

Post by Sirius_Alpha on 25th February 2009, 9:09 pm

HOLY CRAP.

Primary Transits of HD 80606 b
http://oklo.org/?p=319

Photometric and spectroscopic detection of the primary transit of the 111-day-period planet HD 80606 b
http://arxiv.org/abs/0902.4457

Abstract wrote:We report the detection of the primary transit of the extra-solar planet HD 80606 b, thanks to photometric and spectroscopic observations performed at Observatoire de Haute-Provence, simultaneously with the CCD camera at the 120-cm telescope and the SOPHIE spectrograph at the 193-cm telescope. We observed in both datasets the whole egress of the transit and partially its central part, with the same timings. The ingress occurred before sunset and was not observed. The full duration of the transit is between 9.5 and 17.2 hours. The data allows the planetary radius to be measured (Rp = 0.86 +- 0.10 RJup) and other parameters of the system to be refined. Radial velocity measurements show the detection of a prograde Rossiter-McLaughlin effect, and provide a hint for a spin-orbit misalignment. If confirmed, this misalignment would corroborate the hypothesis that HD 80606 b owes its unusual orbital configuration to Kozai migration. HD 80606 b is by far the transiting planet on the longest period detected today. Its radius reinforces the observed relationship between the planet radius and the incident flux received from the star. Orbiting a quite bright star (V=9), it opens opportunities to numerous follow-up studies.

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Re: Eclipse and transit of HD 80606b

Post by Edasich on 26th February 2009, 5:00 am

Excellent. This is the longest period transiting exoplanet so far.

We have a Saturn-sized planet but 4 times more massive than Jupiter. Very Happy
And swinging between the "torch" orbit and the habitable zone too. affraid

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Re: Eclipse and transit of HD 80606b

Post by Lazarus on 26th February 2009, 4:34 pm

Seems that there are two independent groups who published a paper on this. The Fossey et al. paper on exoplanet.eu where the fitted parameters give a radius approximately equal to that of Jupiter.

This is pretty awesome. Much cooler than a stinkin' super-Earth. Wink

Edit: there's yet another paper, on oklo.org... seems lots of people got the end of the transit. The question is whether anyone caught the beginning...

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Re: Eclipse and transit of HD 80606b

Post by Edasich on 26th February 2009, 6:13 pm

Uhm, so we have a planetary radius spanning between 0.86-1 Rj.

Just like establishing if it's Saturn or Jupiter-sized. Rolling Eyes

In any case it's such an important result. I'm very glad.
Wish to see more and more long period transiting exoplanets soon. Smile

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Re: Eclipse and transit of HD 80606b

Post by Lazarus on 30th July 2009, 5:00 pm

More news at oklo.org

The June transit was observed, giving data of the full transit of the planet. Rossiter-McLaughlin shows it is misaligned, and there are improved stellar and planetary parameters.

Conclusion contains the following little gem...
We are grateful to Greg Laughlin, whose enthusiasm and persistence (and, it is suspected, a deal with the devil) led to the discovery of the eclipses of HD 80606.

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Re: Eclipse and transit of HD 80606b

Post by Sirius_Alpha on 31st July 2009, 6:31 am

And it's now on ArXiv
http://arxiv.org/abs/0907.5205

The paper for the misalignment of WASP-14 b had something in the abstract about all the known misaligned planets being several Jupiter-masses, while all the lower-mass planets seem to be well aligned.

Is it possible that gravitational instability produced these misaligned planets, and as the cloud collapsed, the inclination increased dramatically?

Or is that a silly idea due to the length of time it takes for a section of a disk to collapse?

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Re: Eclipse and transit of HD 80606b

Post by Lazarus on 31st July 2009, 4:08 pm

Interesting that the 3 systems with misalignment (HD 80606b, XO-3b, WASP-14b) are all massive and eccentric planets, but the sample sizes are quite small: only 13 exoplanets have had the Rossiter-McLaughlin effect measured.

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Re: Eclipse and transit of HD 80606b

Post by Lazarus on 8th February 2010, 6:29 pm

Complete transit of HD 80606b suggesting a smaller radius for the planet.

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Re: Eclipse and transit of HD 80606b

Post by Lazarus on 7th April 2010, 1:55 pm

Full transit of HD 80606b with warm Spitzer, plus Rossiter-McLaughlin effect measurement.

Suggestions that there may be transit timing variations going on, but this may be due to systematic errors.

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Re: Eclipse and transit of HD 80606b

Post by Edasich on 9th April 2010, 10:11 am

Paper give 5.5 g/cc density for HD 80606 b. Same Earth's density??

Typo or what? :?

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Re: Eclipse and transit of HD 80606b

Post by exoplanet on 9th April 2010, 12:49 pm

This could be ok (I didnīt do the math, though). HD80606b, at 4 Mj, is in a mass range where degeneracy plays an important role in the stability of the planet. For this reason, with such massive planets, as you increase the mass you get objects with similar radius and therefore the density rises. Remember Corot-3b ?

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Re: Eclipse and transit of HD 80606b

Post by Sedna on 9th April 2010, 1:49 pm

Edasich wrote:Paper give 5.5 g/cc density for HD 80606 b. Same Earth's density??

Typo or what? :?

Density is 6.517 (retrieved from my exoplanets' databook). So the density is higher than the Earth's. As esoplanet pointed it out, this is not the first time we see this. Despite Corot-3b has a great density (higher than platinum with 27.178), I don't really consider it as a planet because it has a mass of 21.66 Jupiter masses (that's why I gave it the nickname of "The super-platinum brown dwarf"), so this is not a good example.
The best examples would be WASP-14b (7.725 MJup - 5.001), HAT-P-2b (9.09 MJup - 7.585) and WASP-18b (10.3 MJup - 9.836), with HD 17156b (3.212 MJup - 3.877), XO-3b (11.79 MJup - 8.452), SWEEPS-11b (9.7 MJup - 8.686) and WASP-10b (3.06 MJup - 3.138) running behind.

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Re: Eclipse and transit of HD 80606b

Post by Lazarus on 10th April 2010, 8:38 am

Also it's worth pointing out that a very low mass star like VB 10 can have densities of ~100 g/cc.

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Re: Eclipse and transit of HD 80606b

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