Kepler Discovers Two Planets Transiting Same Star

Kepler is my favorite NASA mission. This mission has the potential to change the way we view the universe. I was extremely disappointed that it was launched with a known flaw. Everybody knew the amplifiers were not working properly and they launched it. http://www.universetoday.com/43856/no-earth-sized-planet-hunting-for-kepler-until-2011/
So, I have to agree with Ken Monroe, NASA is being run by some really smart idiots.
I'm glad they are releasing more discoveries on August 26th. Very exciting!

I'll be happy to eat my words, but my money is on a new-horizon like release, especially after the bravado they put up after the planet candidate count got leaked.

They'll announce some planet that's in a Mickey Mouse orbit around a star that should not have planets or some other such phenomena.

Kepler is on my very short list of favorite missions too... But only one thing counts: What is the statistical distribution of orbit and planet types around which types of stars.

All the rest, including exactly which stars they're around (too far for follow-on observations) is just fanfare.

So here's looking forward to Thursday anyway.

Quality Assurance is sometimes compromised. Fortunately it just makes things all the more interesting for us armchair astronomers.

Folks:

On Space.com I found this comment:

"Scimajor wrote:

Looks like I've scooped Space.com. My contacts are a bit vague but here are the basics.

They're about to announce a system that is "similar to our own" with a planet on the scale of Earth (bigger than Earth but a whole lot smaller than Jupiter) which lies in or near the "habitable zone".

A bit scant on specifics but there you go."

Habitable zone for a small star would be closer so maybe there was enough time for the three passes they what to confirm the planets existence. But habitable zone also has a time component too. Small star don't live as long and that has to be taken into account.

We'll see. Keep digging folks. I'm not going to just wait sittin' on my hands.

tinker

Small star don't live as long and that has to be taken into account.

Small stars actually live longer than big ones.

Dennis:

Thanks for the info. I'll do a little research and bone up on the subject.

oops.... hold on...

BINGO!

http://www.networkworld.com/community/node/65397

Check it out. Betcha.

tinker

Tinker - HD 10180 isn't in the Kepler FOV, so they probably won't be discussing that system on Thursday.

My personal bet is on a system with multiple transiting planets - but I think that you're right that a near Earth-sized planet in the "habitable" zone of an M-dwarf is a possibility. I put habitable in quotations there because tidal effects, the UV flux, and stellar activity would probably make such a planet not a nice place to hang out...

Also, re: the noisy amplifiers mentioned by RayGun. Remember that it's only 3 out of the 42 CCD amplifiers that are noisy! They're still getting tons of good data. I think the team made the right decision trying to fix them in software, given that it probably was going to be a nightmare to take apart and then rebuild the spacecraft's focal plane array.

Folks:

As it turns out HD 10180 isn't even within Keplers field of view. Maybe NASA PAO thought that they would "spruce up" the press conference with this little added tidbit. The press release did say that it was based on Keplers data though.

Still, an amazing find by the HARP team... and right next door too (relatively speaking).

Guess I better grab that ol' shovel 'n' dig deeper.

tinker

SpaceCowboy is right, 3 focal planes out of 42 show degraded noise performance, usable but not to spec. Because of the 4 times/year clocking of the telescope, that means 12 fields out of 42 have one bad orientation per year, i.e. 75% duty cycle at full sensitivity. It's ~100% duty cycle with several-times worse SNR, still good for the larger transits. It's still a damn good mission for every star in the field, and meets the goal performance for 80-90% of them. The "really smart idiots" compared their chances of using it as-is against the chances of making it worse by trying to fix it. They chose correctly, because it's no worse than projected.

The software fix described in your article is almost certainly in the ground processing, not the onboard software. And it'll be done 2 years before they actually need it.

For comparison, CoRoT surveys 8-10 times fewer stars, and every one has 50% duty cycle. Its best sensitivity is for 50 day periods or less, much closer than Mercury. Transit studies from the ground will never be sensitive enough to see Earth-sized planets around Sun-like stars. RV studies can't do it today, and when they do, it'll be from a heroic search of a handful of stars. Kepler will probably see 100 or more, and they'll be reported within 3-4 years.

Tinker, Dennis is right that small stars burn more slowly, and last longer. That allows more time for life to try to struggle into existence. And SpaceCowboy, you're right that M stars are a nasty environment to raise your kids in. But there's ongoing debate over whether such a planet is truly unsurvivable. And besides, we'd like to know how planet formation outcomes depend on stellar mass, primordial disk mass, metallicity, and other variables. So, hospitable or not, planets around M stars are interesting.

Here's my guess about the Kepler announcement. I'd say they've looked beyond 43 days to see how their hottest prospects carry on over a few months, and maybe found one planet that can be confirmed at a Mercury-like orbit. Or one of those with an inner planet. It won't include any candidate planets outside Mercury's orbit. If it's nearly habitable, then it's gotta be a relatively nearby M star.

This is my bet: confirmed planet with lowest known mass around normal star. No pulsar oddities this time, please.

Here's the answer, from this morning's astro-ph:

http://arxiv.org/abs/1008.4141

"LHS6343C: A Transiting Field Brown Dwarf Discovered by the Kepler Mission"

The brown dwarf transits one member of an M/M-dwarf binary. It's also larger than theory would have predicted (but that's not very suprising, since theory has never been tested in this regime).

Folks:

1:15pm and still it's Kepler 101.

op, wait... Two Saturn like planets close to it's sun...

Oh well, "intriguing" maybe for scientists but a wash out for the public. What were they thinking? Haven't they ever heard of focus groups?

tinker

Folks:

The "Kepler 9" system is about 2000 lightyears away. That bodes well for the sensitivity of the Kepler spacecraft.

tinker

GREAT!

Two hot Jupiters (or Saturns). Yawn. One unconfirmed super Earth. Yawn.

Grats, Kepler team! Proud of mediocricy, eh? Wouldn't have happened if all data had been released to the public...

What do I win?
My daughter would offer "one MILLION gallons of... air."
;-)

tinker and Zvezdichko, you're a tough audience - I think too tough. Maybe it's the high bar set by the successful RV community.

This is indeed the first known case of two (and maybe three) transiting planets around the same star. Kudos for that. Yes, we have planetary systems already, but no double-transiting ones until now. Give Kepler credit for doing what it's designed for, and doing it well.

And you seem to be overlooking the absolutely critical importance of the length of Kepler's time record. It has barely gone through 1/3 of the mission, so you won't see the best stuff for another 2-3 years -- no matter who's got access to the data.
(1) Nothing with an Earth-like 1 AU orbit could POSSIBLY have been seen, except with a completely unconvincing 2-blip signature.
(2) Full sensitivity for small Earth-size planets comes from both long observations and several iterations at the data analysis. So finding a Super-Earth candidate is encouraging and maybe technically helpful for the future.
(3) Of course it couldn't find an Earth-sized planet instead of what's really there!

Patience, grasshopper.

No, Papa. I'm not a tough audience. I'm just mad.

First, the Kepler team blames Sasselov and makes my country to look bad. Moreover, Borucki blames Sasselov publicly and says that his claims are misleading. Do you remember this- Borucki: "I'm disappointed one of our members confused people."

Now this very same team makes misleading claims about a potential discovery - hell, this was supposed to be an "intriguing" planetary system. Just take a look at SPACE.COM's comments: "We waited a week for this?"; "Am I the only person who sees these discoveries as the ultimate frustration?".

Shame. Shame. Shame!

*** VICTORY YAWN ***
(it's like a victory dance, but without moving your body and with yawning)

See my prediction from comment #2....

There isn't much astronomical significance to 2 transiting planets... It's only important when the instrument used to observe them is looking for transits... Novelty is in the eye of the beholder.

If the ecliptic plane is very close to edge-on, what else would you expect? And if you're looking at 100,000 starts... well...

Would the Kepler team please confirm the statistical planet orbit distribution they've observed so far? I'll take a margin of error of 25%, that's just fine.

Sigh.

Papa:

You're right, I'm a tough audience... as tough as they come. I was getting autographed pictures of astronauts when I was seven. I "corrected" my grade four teacher about how the Apollo mission would be accomplished (my first teaching experience).

I could think of few scenarios that Kepler could have delivered this early in the mission. But you're right that there were a number of firsts in this news conference. It's the amount of hyperbole leading up to it that I have a problem with. It should have read: "Scientists uncover unique methods of data collection concerning a new solar system detected by Kepler" It would have been more truthful.

tinker

Papa -
That's the company line, but actually quite a lot can be inferred even from one event.

They are not just "counting blinks". They get a lot of data from the shape of the dip in the luminosity. The overall length of the transit, the curve describing the edges of the dip - it's all enough to get a rough idea of what they are looking at.

Of course confirmation requires 3 dips - that's the "slam dunk". But you don't need a slam dunk to draw conclusions from a sample set of 100,000 stars, or ~1000 transiting systems.

And for what it's worth - releasing statistical data won't affect their ability to lay claim to the individual confirmations later, which is their second argument for sitting on the data.

The real reason for sitting on the data is simple. You string the public along, increase anticipation, and can later get more funding. Once you let loose the important data, you become a historical fact, and goodbye funding.

So it's politics as usual, nothing even to get excited over.

This afternoon, I heard the story on a local radio station. Not sure whether the news was local or national at the time. At any rate, in briefly relating the story, they said that "the Kepler spacecraft is in orbit around a star ....". :)

I think, perhaps, that there exists a bit of confusion as to the capabilities (AND LIMITATIONS) of the Kepler Observatory, and consequently the Kepler Team.

1) Kepler can detect the change (dips) in luminosity of a star as a function of time, and infer from that that some of the light from the star has been occluded by a candidate transiting body.

2) In measuring the periodicity of a particular "transit", Kepler's team can determine the orbital period for the candidate transiting body.

3) Given the duration of the light curve (dip), in COMBINATION with the confirmed periodicity (note: this requires at least TWO measurements), they can estimate the mass/density of the candidate transiting body.

3) If there are multiple occultation’s, each with it's own unique periodicity (and each requiring at least two measurements)...one can deduce there are multiple transiting bodies.

4) Finally...and here is the big stretch, from the slight perturbations (irregularities) in the periodicity of the multiple transiting bodies, the Kepler Team has the ability to deduce possible masses of the transiting bodies to a very crude FIRST APPROXIMATION.

5) I can't stress this enough...it is only from independent measurements of the candidate star's shift in radial velocity (from alternative observatories measuring ultra-fine spectral shifts), can a more dependable "accurate" estimate of the transiting bodies masses be determined. The continued and ongoing correlation between BOTH sets of data (mass estimates by Kepler's periodicity shifts along with independent Radial Velocity measurements) will give higher confidence (significantly lower error estimates) on the candidate masses.

This is not such an issue on a stellar system with a single candidate transiting body (with fixed periodicity)...however, with multiple bodies/planets, it becomes much more difficult to make accurate mass estimates solely from the Kepler data, and thus the ABSOLUTE necessity for the two independent methods of measurements. While the Kepler Team did acknowledge that they received independent confirmation from a ground-based observatory using Radial Velocity detection (Keck Observatory)...they definitely downplayed the importance of this, IMHO.

Finally, there is MAJOR piece of information that the Kepler Team conveniently "avoided" discussing in the press conference. And that is the variation in the "habitable zone" (Goldilocks zone) depending on the stellar class. If the candidate star is similar to our sun, then a candidate planet with an orbital period significantly shorter then our Earth will most likely be too close to the star, and too hot to support liquid water. Conversely, a transiting planet (around a Sol-like star) with a significantly longer orbital period, as compared to Earth, may be too cold to allow liquid water.

So far, the Kepler Observatory has only been collecting data long enough to allow for measurement of very short period planetary orbits. This greatly constrains the stellar mass/luminosity which would support an "Earth-type" planet within a habitable zone. In other words, SO FAR, the only possible candidate stars would have to be within a red dwarf size/mass classification. It will only be after many more months (and years), will the Kepler Data be able to expand the range of habitable zones for a more luminous/massive stellar classes. And only then, can they determine if there is a transiting body with a comparable "Earth-like" mass/density orbiting within a habitable zone of a suitable star.

Kepler spacecraft is orbiting our own sun.

The news is no news to me. Stars with multiple planets should be expected and reported earlier by other teams and spacecrafts (European).

Namster, I am sure that Sherlock understands this. I took his post as showing how clueless mainstream media reporters (and editors) can be, when it comes to even the most basic scientific knowledge.