Don't know if it has already been posted, anyway data about all Kepler planets candidates are available online:
http://archive.stsci.edu/kepler/planet_candidates.html

Most of the planets have periods below 40 days... and it's quite obvious, as data have been collected for 43 days; but I don't understand how planets with >100 days period can be in the list.

I can't understrand all of the data: is it possibile to obtain from them planets min/max distance from its star and planet surface temperature?

For example, this planet has 1.5 Earth radius:
http://archive.stsci.edu/kepler/data_searc...pler_id=3541800

But how far from its star is it, and which is (or could be) planet temperature (not considering possible greenhouse effects)?

You can make a rough assumption of the stellar mass from the given stellar radius. Then with the orbital period of the planet in hand, calculate its semi-major axis.

I don't know which formulas to use.

I thought they got stellar mass from things like stellar type. How would you know the radius of the star from direct measurements?

Temperatures you can estimate by balancing the energy from incoming starlight with outgoing thermal radiation (http://en.wikipedia.org/wiki/Effective_temperature)

If you know the brightness and temperature (from colour), you can estimate the radius.



Kepler's Third Law of planetary motion.

I read "K" is 1 for Earth+Sun, but can't understand how to calculate it for other systems.

Indeed, so this is not possible with Kepler alone, right?

Actually, since Kepler is a photometer, it's quite capable of determining a star's brightness and colour, the first of which are how it's looking for planets.


From Wikipedia's page, where P is the orbital period, and a is the semi-major axis.





Since you know three of the four values, you can easily calculate the fourth, missing value.

I don't understand where the temperatures are coming from. 6867155 has a period of 206 days, and the star is 0.927 solar radii. So if the star is mostly Sunlike, and the potential planet has a Venus-like period; why does it have a predicted temperature of 4118 Kelvin? Or are those the star surface temperatures?

That is the star's photospheric temperature.

So to determine how many AUs any planet is far from its star, I have just to divide its period by Earth period?

If that is correct, the most interesting planets are:
id KOI Rp Earth radius Kp Epoc Period (days) Teff (K) Logg (cm/s/s) R* (solar) Semimajor axis(UA)
8018547 902 0,83 8,30 15,8 169,808 83,90 4312 4,616000 0,940 0,229874
10666242 198 3,43 34,30 14,3 86,369 87,23 5538 4,629000 0,806 0,238995
6862328 865 0,63 6,30 15,1 155,237 119,02 5560 4,704000 1,232 0,326085
6867155 868 1,04 10,40 15,2 141,431 206,79 4118 4,517000 0,927 0,566545

Most far/slow planet is 10666242 (83,369 days, 0,24 UA = 36 mln km)

I can't understand how periods greater than Kepler mission length have been determined.

Edit:
wait, I forgot a root...
Ap[AU] = (Pp^2 / Pt^2 ) ^ 1/3

Is this correct?
Then 10666242 semimajor axis would be 0,385 AU?
(87,23^2 / 365 ^ 2) ^ 1/3

Ah, thanks. That makes a lot more sense.

If that candidate is really a planet, it'd be pretty close to the habitable zone -- maybe within it, since that star's a bit smaller and cooler than the sun -- though it's Jupiter-size.

Cassioli,
That formula is only valid for the Solar System (or a very close to Sun mass star). The constant Sun mass cancels out on both sides of the equation, leaving the relationship between period and distance. To calculate, I think you want the gravitational formulas, available here:

http://en.wikipedia.org/wiki/Orbital_perio..._a_central_body

Given an estimate of the central mass based on stellar type, a distance can be calculated.

Right, a photometer measures the amount of light. But to determine colour you need at least two wavelengths where you measure the light. From browsing the Kepler website and wikipedia, it seems they only measure the light throughout the entire 400-850 nm band and there is no spectral resolution. Hence no colour determination.

All the stars Kepler observes should be well known from previous sky surveys and other observations. After all they are relatively bright stars, all Kepler is adding is a huge amount of constant photometry for each. Therefore a lot of basic characteristics of the stars should be already known beforehand. Additionally I am sure Kepler scientists will request additional observations of candidate star systems.

I think the Kepler site itself has a nice explanation of what they do.

http://www.kepler.arc.nasa.gov/Science/cha...ticsOfTransits/

--Greg

The latest update has arrived here. Biggest news: there will be a discovery announcement in early November. Next biggest news: Kepler 9d, the hot superearth, will soon be upgraded from "potential" to "planet."

Kepler insider, "Dr. Jason Steffen of Fermi National Laboratory in Batavia, Ill., will shed light on NASA's recent ventures in the stars during the Harry Nelson Endowed Lecture of Astronomy on Thursday, October 21, at 7:30 p.m." at Augustana College in Rock Island, IL. For more information, see here.

I'm looking forward to early November. Reason 1: The US midterm elections will be over, so no more political attack ads on TV. Reason 2: Anticipating a Kepler discovery announcement.

It was what, 6 months ago that somebody on the team remarked that NASA HQ had asked them for a press release in November, to be followed by another one a few weeks later. Followed by the big AAS meeting in Seattle in February, which is as noted by Bill Borucki is when they'd have something real to discuss.

I'd expect the press release in November to contain a few more confirmed planets, which is certainly exciting in its own right.

The Kepler Asteroseismic Science Consortium (KASC) at Aarhus University in Denmark will hold a media teleconference on Tuesday, Oct. 26, at 11 a.m. EDT to discuss the latest discoveries about stars and their structures using data from NASA's Kepler spacecraft." (full release)

Probably not an announcement of planets based on the wording, but probably a significant announcement nevertheless...

The talk turned out to be a nice summary of how Kepler is contributing to the field of asteroseismology. Slides are here.

I'm reading through "The Occurrence and Mass Distribution of Close-in Super-Earths, Neptunes, and Jupiters" authored by Howard and Marcy from UC-Berkeley and a bunch of other people. The official release is behind a paywall:

http://www.sciencemag.org/cgi/content/abstract/330/6004/653

but if you search the title in everybody's favorite search engine you can find it at the Keck web site (I won't paste the link without permission).

Regarding Kepler:

It's also available here: http://arxiv.org/abs/1011.0143

http://www.foothill.fhda.edu/ast/news.htm#Anchor1

Interesting quote from Geoffrey Marcy in a recent space.com article:

"Many of the candidates Kepler discovered are now getting verified with radial velocity confirmations. 'On Feb. 1, we'll announce all of them — a huge avalanche of exoplanet candidates,' Marcy said."

The paper "Discovery and Rossiter-McLauglin Effect of Exoplanet Kepler-8b" (Jon M. Jenkins et al 2010 ApJ 724 1108) has now been published online.

That's behind a paywall.

Here's a free one: http://arxiv.org/abs/1001.0416

It's interesting to go to the AAS Seattle Meeting website, type "Kepler" into the advanced search "abstract body" field, and hit return. There are three pages of results, most of them dealing with the mission (rather than the astronomer, for instance, although there are a couple of talks devoted to him, too). Of course the abstracts don't provide any big "reveals," but they do whet your appetite for what will be an exciting meeting--and in just 7 weeks from now.

Some of the rest of us, planning (say) Hubble image releases, are desperately hoping that the Kepler people will not make the Big Announcement on the same day! Another reason to prowl the AAS abstract search, though lately I expect more from the February 1 announcement which would coincide with the big public data release.

Latest status

Interesting details of the upcoming February anouncement, and future data release.

Recent ground based follow up season is over.

Kepler meets citizen science! From the people who brought you Galaxy Zoo, Solar Storm Watch, Moon Zoo... now there's Planet Hunters. This interface lets people interact with light curves from the growing Kepler public archive, especially to look for transits that the pipeline software might have missed, for example due to stellar variability. (I had the chance to talk with Debra Fischer about this before it went into testing, and it should be a powerful approach). If previous Zooniverse projects are any guide, there will be additional interesting byproducts that we didn't know to look for in advance.

That looks really cool

edit - aaaargh...sucked in!!!

New manager's update: Safe Mode Update

http://www.kepler.arc.nasa.gov/news/mmu/in...s&NewsID=91

They're stopping science operations until next week to decide whether to switch to backup hardware.

Rats.

The press release didn't provide any specifics about what function(s) were impaired/otherwise affected. Is this mission hardware, bus, power generation...?

(new here!)

I used to do engineering and ops for Kepler, so I can shine some light on the situation...

I haven't rummaged through this whole topic/thread, so I don't know how much it has been discussed here. But the most common problem that Kepler has is with the Star Trackers. They have caused more safe mode entries than anything else, by far! The issue for this most recent safe mode regression is the same. This season, especially during the roll to this new attitude in December, caused a lot of problems the first time we did it last year. Each season is unique in many ways.

There are several contributing factors to this. One, the flight software has a complex way of maintaining pointing... not a trivial thing when you have two different kinds of hardware (star trackers and the fine guidance sensors) maintaining pointing. Two, the star trackers are flaky. They buzz out all the time, dropping guide stars, thinking that radiation events are new stars, etc.... it gets messy real quick. The hardware is not top-of-line, either.

Thanks for the info! Please stick around!

This is kind of a vague statement in regards to Kepler, but it makes sense for a few of the redundant components on board. For instance, everything like the computers, interface boards, etc. are dual-string (and cross-strapped!) as we might expect; they actually use the B-side as the primary side. However, the culprit is often the Star Trackers, and Kepler uses both of them all the time.

But it's still interesting to see that the A-side wouldn't have responded in the same way, according to that report. I wouldn't have guesses it based on my experience with that spacecraft.

Either way, she's still a marvel! Undoubtedly my favorite spacecraft of all time, maybe with the exception of the Mars Rovers (a project with which I am now employed!).

I spoke to my former colleagues at LASP and BATC, and here's what actually happened...

I was mistaken. This most recent regression out of science data collect mode to Safe mode was NOT due to the Star Trackers, but rather due to the Coarse Sun Sensors. It occurred during the roll maneuver from the Fall attitude to the Winter attitude. (Actually, it was't QUITE that maneuver, since they don't do pure season-to-season roll maneuvers; during the quarterly contacts with the DSN, they roll out of the current attitude to their science data downlink attitude first, and then from THERE they go to the new season's attitude. It's almost a pure roll anyways, but the SDDL attitude is an intermediary.)

At the beginning of the winter season, the spacecraft is peering "over" the sun to point at the star field for science collection. Therefore, the sun avoidance volume is as close to the photometer boresight as it's ever going to get over the year. It's only a few degrees -- less than 10, from what I remember last year. So the margin for error is small. This caused a problem at the end of January last year when the Star Trackers fuzzed out for a bit, which is a common occurrence, so the spacecraft went to an internal attitude propagator. This propagator told the computer that the boresight was in the sun avoidance zone, and BAM, Safe Mode! The story there is a bit more complex, but that's the gist.

This time around, the *sun sensors* had a glitch that spat out a measurement that put the apparent position of the sun in the sun avoidance zone. It was only a few degrees, but again, Kepler is in the season where its science attitude is close to the sun avoidance zone. This sun sensor behavior was strange to the Kepler engineers because the A-side and B-side computers, which are both always powered but the B-side is prime (I know, silly!), calculated different positions of the sun. The B-side computed the faulty one, and since it's prime, it safed the spacecraft.

They have since run tests where they slewed back to the winter science attitude and saw lots of sun sensor noise on the B-side but none (or very little) on the A-side. Same sensors, different measurements. Odd, indeed!

I am privy to more information (I do work with a guy who works on Deep Impact, another BATC spacecraft), but that's about all I'm able to tell without getting in trouble.

-fs

New discovery to be announced today:



This announcement will be followed by online chat with Dr. Natalie Batalha:

http://www.nasa.gov/connect/chat/kepler_chat.html

NASA'S Kepler Mission Discovers Its First Rocky Planet:

http://www.nasa.gov/topics/universe/featur...cky_planet.html

KEPLER-10b

1.4 Earth radius
4.6 Earth mass
8.8 g/cm3 density
Orbit .01684 AU

SuperMercury?

KEPLER Team dubs it Vulcan

http://www.nasa.gov/topics/universe/featur...cky_planet.html

Craig

Yikes!

Solid iron world.

Or perhaps a rocky mantle with a uranium core.

"Measuring 1.4 times the size of Earth, it is the smallest planet ever discovered outside our solar system. "
Erm, what? Someone forgot about pulsar planets. -.-

Pulsar planets? Never heard of those

I created an RTF formatted log of the chat session. Made it in Wordpad so open it with that if it doesn't format nicely for you:

http://paranoid.dechengst.nl/text/Kepler%2...10-JAN-2011.rtf

These online Q&A sessions really make me appreciate what we have here at UMSF.

9 out of 10 questions could have been answered by a single page on Wikipedia. 19 out of 20 questions with a few clicks on Google.

I suppose the chat sessions are more for reaching out to Joe Public than anything else, so that's good. Still, I can only endure so many "does it have life?" questions.

Dr. Batalha did say there's another signature at 45 days and 2x Earth radius.

Now THAT is a critical mass!

...The end result of turning the heat up to #11 on a hot Jupiter?

Andy

http://en.wikipedia.org/wiki/Pulsar_planet

At most, this discovery could be named "confirmed lowest sized planet around normal star". Not that this is small thing, of course.

BTW I know that size of pulsar planets are unknown, but I somehow doubt that 0.020 M⊕ is larger than this small melted speck of cosmic iron dust.

It would have been more accurate to say "smallest measured radius."