HAT-P-7 b, the planet observed by Kepler may also be in a retrograde orbit. There is also evidence of another, much more distant planet based on radial velocity measurements.

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Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.
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More planets:

• 11 UMi b
• HD 32518 b
• HD 86264 b
• HD 87883 b
• HD 148427 b

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Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.
-- Richard Feynman

Two planets from the Keck Observatory:

• HD 73534 b, a cool Jupiter orbiting at 3.15 AU in a circular orbit
• HD 179079 b, a hot Neptune

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Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.
-- Richard Feynman

Mini-stampede today.

• Planetary companions around the K giant stars 11 UMi and HD 32518 -- two super-Jupiters in intermediate period orbits around K giants
• Five planets and an independent confirmation of HD 196885Ab from Lick Observatory -- five Jovians in long period orbits
• Two papers discovering the retrogradeness of HAT-P-7b. The first retrograde planet to be discovered according to one, though the WASP-17b paper hit the preprint server a day earlier.

Ok ok, you win this round.

Guess these discoveries are related to the IAU General Assembly being held in Rio de Janeiro...

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Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.
-- Richard Feynman

WASP-18b, hailed as an "impossible" planet. Why? This 10 Jupiter mass orbits its star every 0.94 days. Tidal friction should cause the planet plunge into its star within a million years. Quite unlikely that we could find a planet in such a phase. Or not, we may not understand the tidal process correctly.

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Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.
-- Richard Feynman

Wow! So how long before we can get a close approximation on its decay rate? A month or two?

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The article is saying that we may be able to time decay effects within a decade...

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I saw the 28 second decay prediction after a decade but the observable transit accuracy has got to be far better than that. But that is sorta my real question; how accurate is multiple cycle transit data? If it is close to a second, then in 4 months something should be noticeably different. Or would the math models (standard deviation?) cut this considerably so that in a month or so we might be close to an answer?

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I'm guessing they'll need at least a decade to separate any decay effects from instrument noise, margin of error, and so forth--even if it would be theoretically detectable in a shorter time frame.

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--The State

Maybe so. Of course, an exoplanet this size and close to its host should produce some quality Dopper data, too. I wonder if this will give us a quicker answer.

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Actually, it isn't. Determining the exact time of a transit
(for example, the exact time of mid-transit) is not easy.
The best ground-based work has uncertainties of
around 60 seconds. See, for example,

http://arxiv.org/abs/0901.0343
http://arxiv.org/abs/0908.1705

I've done some work in this area myself, and as Romanus
said, there are a LOT of sources of error in the timing.

Thanks! I was always curious about that, but it wasn't that interesting to me until this planet came along. It would be really something if this planet is very close to its final nose dive.

Based on a quick search, neither of those papers refer to a Doppler alternative. Is it likely in this particular case that the Doppler data would improve decay rate accuracy compared to transit photometry?

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The impossible planet, eh? Perhaps we should get Dr Who to check it out.

Something seems wrong here; if it is a planet just about to crash and burn into its sun, it can't have been there very long; a few million years at most. Is that likely?
Perhaps it isn't a planet at all, but some other phenomenon we don't know about yet.

Alternately, they seem to suggest that the tidal friction effect might be lower than expected, allowing the planet to have been in that location for a longer time in the past. How feasible is that, I wonder.

Hmmm... it may even be a megastructure of some sort. An artificial, large scale object placed there recently.

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"A few million years" is on the order of 1/1000 of a star's lifetime. If every star has, on the average, one such situation in its lifetime, then stumbling onto one after finding planets around 300+ stars is not that surprising.

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Fiction has to be plausible. Reality is under no such constraint.

There are some stars supposedly classified as "flashing stars". V838 Mon is one (it has 3 known flashes, I think) and I have forgotten the other one. One explaination is the crashing planet scenario.

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That is an interesting thought. Perhaps some, or many, planetary systems are considerably more dynamic places than our own. In some systems planets might interact with each other dramatically, flipping each other into different orbits, and planets might migrate inwards or outwards as a result. Something similar seems to have happened in the earliest period of the Solar System's existence, IIRC.

That raises a couple of more questions though. Is this a particularly young system? Or is is an old stable system which is undergoing some relatively rare event?

If it is a rare event, have any other main-sequence stars ever been observed to consume a close-orbiting planet? That would be a fairly high-energy event, I think, and would cause a flare or brightening of a detectable kind.

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Ah, I see George has answered my question already.V838 Mon isn't a main sequence star, though, is it?

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According to Wiki, it may be a pre-main sequence star. Interestingly, it apparently has a 4 or 5 Solar mass companion. [Note the last sentence to the Wiki article, which states that the number of annual "crash and burn" planets into the more massive hosts may be a couple times per year, versus about 1 C & B for every 2 years for the Solar mass host stars.]

Paul Cresswell has been involved with some papers on planetary migration. He jumped in with us here (and a few other places IIRC) on Baut a few years back.

Here is one paper he co-autorhed:

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Wow, this is really interesting news! Has anyone considered that perhaps this 'planet' is actually a Death Star set in it's peculiar orbit by an amazingly advanced alien civilization?

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Please don't post scifi nonsense in this thread.

WASP-18 b, 10.3 Jupiter-mass, 1.11 Jupiter-radius object in a tight 0.94 d orbit. Expected to have strong tidal interactions with the host star lowering its orbit to tidal disruption in perhaps under 1 Myr. It's orbital period will probably be monitored over the next few decades to try and measure dP/dt.

http://www.nature.com/nature/journal...ture08245.html

CoRoT-7b & c

Hot dang, our director is on CNN!!!

Well, I'm hoping the paper will finally appear on astro-ph tonight.

He gave a presentation at the institue last week telling us about the parameters, and admonishing us that it was all top-secret...

Concerning the radial velocity curve, Mike Endl asked why there were like NO outliers (there was a single one), and Artie just shouts: "HARPS has no outliers!!!"



It really is an awesome instrument.

By the way, our institute is NOT the "Thuringer observatory"... Sheesh, you American journalists...

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David Alexander Kann
PhD student
Thueringer Landessternwarte Tautenburg

Ignite our minds and let's burn brighter
These are the wonders at your feet
- Dark Tranquillity, The Wonders At Your Feet

Congrats! I wish I could treat y'all to Rocky Road ice cream.

Wow, that baby's flying! It's traveling at about 800,000 kph.

I wonder if it will burrow its way into its host relatively soon?

At 5275K for the host, why is it classified a K-class star and not a G-class? [I won't comment on the color chosen for this star in the art work at the link. ]

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Where did I hear this predicted? Someone said something along the lines of

At 5 M_E the density is about right for an all rock planet, if the 1.67 R_E figure is holding up. I think a rock planet with a large metal core would be denser than that.

Could this be a 'chthonian' planet? Or is that classification not useful in this context?

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Spectral types are determined by spectral lines, not necessarily by temperature. It's just a nice convenience that stars of similar spectral types have similar temperatures.

Though, 5,275 K is hot for a K-star, CoRoT-7 is of spectral type K0, which means it's only one step away from being a G9, which commonly have temperatures around 5,400 K.

With an Earth-like density, I would say "probably not", but I'm not 100% sure on that.

Thanks, I overreacted. Also, stellar classification charts vary among themselves the temperature range for each class.

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