Mind, these are still only 'candidates', and unconfirmed so not time to party just yet (but worth keeping and eye on!)

so many M-class possible planets!

Yes, but the Kepler team has done a variety of studies to show that their false positive rate is very small. So 95-99% of their "candidates" are planets.

It's in the "Supporting Online Information," and it references these two papers:

An Emperical Condition for Stability of Hierarchical Triple Systems

Long-Term Stability of Planets in Binary Systems

The SOI says that in addition to the criteria given in these two papers, their own long-term integration suggests the orbit is stable.

--Greg

It's an exciting discovery, but frankly I'm not surprised.

One thing we seem to find with almost repetitive regularity is that Nature always finds a way to do the unexpected.

That's probably entirely due to the fact that we are limited in our imaginative capability...but, that's okay.

That's precisely why we explore.

Thanks Greg. So if I understand correctly the newly discovered planet is close to the inner limit for stability - a hint perhaps that it is the innermost member of a dynamically 'full' family.

That's what I get. The report puts the planet at 0.70 AU from the barycenter. Using the formula from Holman and Wiegert, the limit for stability around the pair is at about 0.65 AU, so we probably shouldn't expect anything closer, unless it just orbited one of the two stars. In that case, though, the outer stability limits are 0.068 and 0.032 AU (respectively), so they'd be quite toasty.

By contrast, the limit around Alpha Centauri AB is 87 AU, so nothing closer than that is likely to orbit the pair. On the other hand, the individual limits for A and B are 2.8 and 2.5 AU, respectively, so planets in the habitable zone of either star should be quite stable; there just likely wouldn't be any outer planets.

--Greg

So if planets were actually orbiting in the habitable zone, they'd likely have little protection from bombardment?

-kap

If you're talking about the lack of gas giants, who needs them when each star has the other star? Sounds like everything out to 87 au will be cleared out.

Yep. No stable orbits from about 2.5 AU out to 87 AU. Any debris would be swept into one or the other star or ejected from the system entirely. This occurs very quickly--millions of years at most.

--Greg

http://www.spaceref.com/news/viewsr.html?pid=38486

Two new planets found by the public in the Kepler data archive from the first 90 days of data. Both are hot super-Earths/sub-Neptunes.

Not with those radii!

The one is 2.65 R-earth, so that's less than Neptune. The other, you're right, is 8 R-earth, which is about twice Neptune's.

Thanks for the correction.

Does that imply there can be no close-in "hot Jupiters" either? (Since presumably they would need to have migrated in from the "forbidden" zone.)

That seems reasonable. Hot Jupiters aren't expected around either component of a two-star system with low separations. Some counterexamples like Gliese 86 have one component being a post-RGB star, and can be understood by considering the evolution of the system.

I guess the reasoning is that hot Jupiters form outside the ice line before they migrate in, and, clearly, that can't happen with a system like Alpha Centauri. What's not clear to me, though, is whether something unusually big could form inside the safe zone during the period when all that matter from outside the safe zone is still whizzing around. (Safe is a function of semi-major axis and ellipticity, so lots of stuff in unstable orbits would invade the space that's safe for circular ones.)

But I guess I do know which way to bet. ;-)

--Greg

Kepler-18b, 18c, and 18d have been announced. They are a super-earth class planet and two Neptune class planets in close orbit around a sun-sized star. Kepler-18c and 18d are in a slightly out of phase 2:1 orbital resonance. Kepler-18b is described as being "validated" rather than "verified," since its existence has been confirmed by a probability argument based on the absence of apparent background objects in a high resolution image obtained with the Palomar 5-meter telescope. If we set the bar at validation, the discovery process for smaller planets should go considerably more quickly.

There is finally a new mission manager update here. The most important points are: (1) "This was the second full quarter in a row with no significant anomalies or unplanned science breaks"; and (2) over 200 abstracts have been accepted for the First Kepler Science Conference at NASA Ames Research Center Dec. 5-9.

More information about the conference is here. The sessions will include:

• Asteroseismology Across the HR Diagram
• Earth-analog and sub-Neptune-size Planets
• Eclipsing and Interacting Binaries
• Ensemble Asteroseismology of Solar-type Stars
• Exoplanet Theory
• Extragalactic and Other Astrophysics
• Giant Planets and Planet Atmospheres
• Multiple Planet Systems
• Red Giant Oscillations
• Stellar Activity and Rotation
• The Kepler Mission and Exoplanet Statistics

Lastly, there is an article about progress on the mission extension proposal at Space.com here.

Very good news; but the anomalies were clustered in winter (due to the apparent sun proximity to Cygnus). Let's cross our fingers for the next quarter.

The First Kepler Science Conference
http://kepler.nasa.gov/Science/ForScientis...FTOKEN=16036309

Dates:
December 5-9, 2011

NASA will host a news briefing at 8 a.m. PST, Monday, Dec. 5, to announce new discoveries by the Kepler mission. The briefing, during the Kepler Science Conference, will be in building 152 at NASA's Ames Research Center at Moffett Field, Calif.

The briefing will provide an update on the statistical findings since Kepler's Feb. 1, 2011, science data release and introduce a new confirmed planetary discovery. The briefing participants are:

-- Pete Worden, center director, Ames Research Center
-- Natalie Batalha, Kepler deputy science team lead at Ames
-- Bill Borucki, Kepler principal investigator at Ames
-- Jill Tarter, director of the Center for SETI Research, SETI Institute, Mountain View, Calif.

http://www.spaceref.com/news/viewpr.html?pid=35415

A live stream of the Kepler Science Conference will be available at:
http://connect.arc.nasa.gov/kepler

PDF of the conference sessions with complete abstracts
http://kepler.nasa.gov/files/mws/keplercon...21Nov_print.pdf

We are in an era of a star trek but without the starships.... for now we chart courses for the starships, unmanned or crewed, of the future.

Craig

Will that be the only streaming link? It's not on the NASA TV schedule....

Only link I know of is the one for the arc stream

I checked the NASA schedule too and did not see it. Still going to check around NASA TV at 8:00 PST (11:00am EST). Their schedule listing is not always accurate.

Here we go:

http://www.nasa.gov/mission_pages/kepler/n...n-briefing.html

Summary by Bad Astronomer:

http://blogs.discovermagazine.com/badastro...-sun-like-star/

And the predictable headlines:



http://news.google.ca/news/story?q=kepler+...ved=0CDMQqgIwAA

The Habitable Exoplanets Catalog

MOD EDIT: One thing missing here is the word "potentially" just before "habitable"; let's please keep that firmly in mind for this discussion.


2 Confirmed Habitable Exoplanets
14 Candidate Habitable Exoplanets

28 Confirmed Habitable Exomoons
6 Candidate Habitable Exomoons

Exomoons are inferred from planetary dynamics, but none observed yet. (Mongo: I assume that they have been detected via transit timing variations)

Update: The recent confirmation of Kepler 22b (KOI-087) does not qualify as a potential habitable exoplanet on the catalog. It is in the habitable zone of the star but it is also too big and classified here as a Warm Neptunian. Most of the interesting exoplanets in our catalog are Kepler objects too just waiting for confirmation as Kepler 22b did today.

Marcy presentation RV Follow-Up of Small Planets from Kepler: Verification, Masses, and Densities ... Marcy states the limiting radius for a rocky world (something you can walk on and not be underwater or wading through a deep extended H2 atmospere) is 2.5 Earth radii. Wonder how much pressure at the surface of one of these H2 extended atmos planets one would feel at the rocky surface. Or are all H2 extended worlds all so volatile rich, a global ocean will always be present?

New worlds!!!!

wow

Today's Kepler press briefing

http://www.spaceref.com/news/viewpr.html?pid=35425

The announcement included moons? I didn't see that anywhere in the press release. Do they discuss it in the briefing?

And the "Adding Two and Two to Get Ten" Award goes to...

(opens envelope)...

http://www.dailymail.co.uk/sciencetech/art...o=feeds-newsxml

Very well presented conference on this new discovery ..Next major step is determining the mass(and hence density) of the planet so as to better characterize it interms of whether it is likely to be rocky type(Earth-like) or more like uranus/neptune type if I understood correctly. I would assume that atmospheric measurements will be possible by spectral analysis in the near future. How do they actually get to measure planetary mass ??

ye olde radial velocity technique that revealed most of the known exoplanets before Kepler was launched provides a measurement for the mass with an uncertainty due to the unknown angle between the line of sight and the plane of the planet's orbit. In the case of transiting exoplanets you know that the angle is practically zero, so the technique directly gives the value of the mass.

Thank you! I'd been monitoring space-multimedia.nl.eu.org and youtube.com/user/NASAtelevision waiting for this to pop up, and was disappointed that it hadn't appeared.

For anyone who is scanning this thread looking for a Youtube clip, here it is:

http://www.youtube.com/watch?v=en5OObU0ryU

Kepler’s Quest for New Worlds Public Talk
Dr. Natalie Batalha & Dr. Don Kurtz for a free public talk on NASA's Kepler Mission

http://connect.arc.nasa.gov/p458cqu9hr4/

Have not had time to watch this yet... enjoy

Craig

Awesome that they end with a quote from Rui. Kepler's success is so inspiring, I really hope this is a driver for getting the next generation of telescopes; Kepler-like spacecraft that can map multiple fields of view as well as the Terrestrial Planet finder chronograph and interferometer. WFIRST is set for launch in 2022, but I think it's the only new planet hunter in the works. /sigh

For those in the CA Bay Area:

---------------------
SETI Institute in Sunnyvale
Wednesday, December 7, 2011 - 7:00pm
The Search for Habitable Exoplanets in the Kepler Era and Beyond
Sara Seager
Planetary Science and Physics, MIT

For centuries people have wondered, “Are we alone?” With hundreds of planets now known to orbit other stars, we are finally able to begin answering the ancient questions, "Do other Earths exist? Are they common? Do any have signs of life? NASA's Kepler space telescope will soon tell us the statistical numbers of Earth-size planets orbiting sun-size stars. Beyond Kepler is the search for potentially habitable worlds around nearby, sun-like stars. Professor Seager will discuss how astrobiology and space engineering research will come together to enable us to discover and identify other Earth-like worlds.
---------------------

If you've got any questions let me know and I'll try to ask.

KEPLER Science Conference sessions are being archived here: scroll down the page in the link
http://kepler.nasa.gov/Science/ForScientis...rence/sessions/

Craig

These talks at the SETI Institute appear on youtube.com/setiinstitute a few weeks later.

Just FYI...Kepler has NOT found any exomoons let alone habitable exomoons, despite what that website that Mongo posted says. Geoff Marcy said that unequivocally yesterday at his Sagan Lecture at AGU.

I dug into the site, and it appears that when they are talking about exomoons, they mean gas giants that are sufficiently large to plausibly host orbiting Earth-like moons.

The Mass and Radius of Potential Exomoons

Latest List of Potential Habitable Exoplanets and Exomoons

They are using the same planet to moon-system ratios seen in our solar system for the gas and ice giants (Jupiter, Saturn and Neptune all at about 3000:1, Uranus at about 10000:1)

They then use this ratio to estimate the mass of the largest plausible moons of gas giants that are already known to be in the star's habitable zone.

So yes, the exomoon numbers are speculation based on solar system statistics. They do state on the home page that no exomoons have been observed yet, but they could be more clear that the listed exomoon statistics are conjectural.

http://www.nasa.gov/news/media/newsaudio/index.html

Another Kepler media telecon tomorrow (Tue.)

Is there a schematic view of this new Kepler-20 system? Sounds like it's Neptune, Mars, Neptune, Earth, Neptune. Within the orbit of Mercury. Crazy.

[edit] There are at least videos in the presskit:
http://www.nasa.gov/centers/ames/events/20...0-presskit.html

[another edit] My wish fulfilled, by space.com:
http://www.space.com/13987-earth-size-alie...nfographic.html

Awesome news.

Kepler began recording scientific data in April 2009 I think? If so, we passed 25 months this past May. We should expect the data for Earth-size planets in Earth-distance orbits to start rolling through the pipeline about now. 25 months of Kepler observation would be the minimum, and 36 months would be the maximum.

I would expect a flood of really exciting announcements this time next year, after the northern hemisphere observation season has ended. It's been a long 2.5 years but we are almost there!

It will take a long time to detect an earth-ish planet inside the several-year orbit of a Jupiter. I hope Kepler stays online long enough to find some good candidates!

Journal publications are here:

Two Earth-sized planets orbiting Kepler-20
http://arxiv.org/ftp/arxiv/papers/1112/1112.4550.pdf


Kepler-20: A Sun-like Star with Three Sub-Neptune Exoplanets and Two Earth-size Candidates
http://arxiv.org/PS_cache/arxiv/pdf/1112/1112.4514v1.pdf

Nutty system....

Craig

Should we treat Kepler-20 as a freakish exception? If so, here's my wild guess at how it formed: flyby/merger with another star that resulted in lots of ejections, some additions, and inward migration of the survivors to stable orbits? I'll leave the math as an exercise to the reader.

The astromers didn't toss this out as an idea, and instead suggested its time to rehash planterary formation models. This makes me think they want to include this black sheep into the family. Come here 20-c, let have a group hug.

In that context, there could be an earth-ish planet in a verrrrrrry long comet-like orbit around its adopted star, that experiences habitable temperatures every 20k yrs or so.

Very briefly every 20k years. I've always been amazed at the "hang time" long elliptical orbits have. Objects in such orbits essentially spend all their time near apastron. I think the Russians use this for their communications satellites.

--Greg

The Kepler-20 orbits are not that elliptical (e<0.6). Objects in highly elliptical orbits would be even harder to detect with transits near periapsis being very short, and transits for most of the orbit being too long to track unless the period is really short, e.g. an object in an star-grazing Aten asteroid-like orbit.

(The Russian comsat orbit [Molniya after the comsat name] is pretty specialized. The period is 12 hours and the inclination at 63.4 deg is such that the argument of the periapsis is not perturbed by Earth's oblateness. 11 of the 12 hours is over the northern hemisphere, and the ground track and the antenna tracking repeats daily. US also uses this type orbit for data relay to users north of about 70 deg N where GEO satellites would be close to if not below the horizon.)

How many of the 150,000 stars in the Kepler survey are expected to spin edge-on to our perspective and thus potentially have planetary systems that can provide transits that register on Kepler's survey?

What are the chances of a system like Fomalhaut's existing in the survey slice? Do we already know of any stars or planetary systems spinning or orbiting at an angle similar to Fomalhaut's within Kepler's survey area?

I've poked around a bit, can't find answers. Anyone know where to look?

Google came up with these:

Perhaps not a perfect answer but in the Kepler press kit it says: For a planet in an Earth-size orbit, the chance of it being aligned to produce a transit is less than 1%.

There's a very good spreadsheet and other information on the Planetquest website which gives a complete (as can be) list of exoplanets and their locations. Haven't conducted my own survey but you may be able to check the answer here. (Excel file: 350kb)

Thanks Astro! The PlanetQuest spreadsheet is a great, concise list. Thinking of Fomalhaut b, spotted in two HST pics in its 872-year orbit - if that system were aligned for transit observation, the transit itself might take months or years!