Kepler 4b - 8b: First Planets from Kepler

planet around red dwarf ?
http://kepler.nasa.gov/news/nasakeplernews/index.cfm?FuseAction=ShowNews&NewsID=15
The Big Reveal

Here's a question...if Kepler comes up with null results in this batch of data, could that simply mean that giant planet migration is not as common as assumed? I mean, if a gas giant has a period of 12 years, it would be a shot of pure luck if one transited within the space of less than half a year! We know from measurements already taken of circumstellar discs in the Orion Nebula that about 15% of stars have at least Neptune sized planets. Wouldn't a result of no rocky or gas giant planets at this point point to either longer periods being common (even around M-Dwarfs) or perhaps (gasp) a technical problem with the probe?

Kepler is doing alright, it was able to detect the secondary transit of HAT-P-7 b, demonstrating the ability to detect the transit of an Earth-sized planet.

We can tell from CoRoT, SuperWASP, HATnet, XO, TrES and SWEEPS that Kepler-type searches for planets produce results. If this announcement does not involve new planets from Kepler than it more likely means that radial velocity simply hasn't had time to confirm the candidates, as they orbit dim stars.

tachyonic wrote:

We know from measurements already taken of circumstellar discs in the
Orion Nebula that about 15% of stars have at least Neptune sized planets

We know from HARPS that the value is at least 38 - 58%. (see here)

Don't expect rocky worlds in this release, or even Neptunes. It's too early for that.

Borislav, that image seems to be showing how the habitable zone of planets varies for the temperature of the star, but otherwise it's hard to glean much from it.

From the abstract of Bill Borucki's talk at the AAS meeting.

Quote :

However ground-based follow up observations confirm the discovery of
exoplanets with sizes ranging from 0.6 Rj to1.5Rj and orbital periods
ranging from 3 to 9 days.

So, I would guess several new hot-Jupiters/Saturns, as would be expected at this stage with perhaps some hint of multiplicity in some of these systems.

Thanks the the confirmation/clarification Sirius_Alpha. I was unaware of those new percentages! It's hard to find good statistics, and the stuff that makes it to the popular science mags is lacking in qualifications for their numbers way too often. Do you work in any of the the planet-hunting programs at all?

According to

http://arxiv.org/abs/0912.1171v1

Neptunes are at least three times more common than Jupiters beyond the snow-line (95% confidence).

I don't recall the reference (I seem to have wrote it down without a reference) but from ELODIE, 0.7% of stars have a planet more massive than 0.5 M_J in a period < 5 d, and 7.3% of stars host such a planet in a period < 3,900 d. Keck found 0.65% and 8.6% for the same mass and period ranges. But planet-formation theories suggest most gas planets form beyond ~3 AU, so it's estimated that Keck and ELODIE only picked up 6% of the gas giants.

~25% of stars with twice the metal content of the sun host at least a giant planet, but only 3% of solar-metallicity stars have one.

For the radial velocity programmes like Keck and ELODIE, 6% of stars surveyed have readily detectable giant planets. The percent of those systems that are multiple is ~12%. For surveys with the longest duration, the fraction of multiple planet systems range from 25 - 50%.

The statistics that surveys are able to place depends of course on how successfully they detect planets around their target stars. Since HARPS is so wonderfully accurate, we're able to finally probe that population of low-mass planets that models suggested were there. Kepler should provide a sturdy census out to at least an AU around sun-like stars.

I personally am not involved with any planet surveys. Just graduated high school. That is, however, a goal of mine.

The transiting planets could be almost anything, not just the usual hot-Jupiter types.

It's possible that a transiting Earth-mass planet in the habitability zone of a main sequence star may have already been detected. Maybe not around solar-type stars, but certainly possible around stars much smaller than the Sun, even though there is only 90 days of Kepler data so far. For example, an Earth-mass planet in the habitability zone of a 200 Jupiter-mass star (which would be about M5V) would have an orbital period of roughly 15 days, which means that it would take just 45 days to confirm that the planet is for real on the basis of the transit signature. A reminder of this possibility is Gliese 1214, with its transiting planet discovered by the MEarth project even though the project had benn running for only a short time.

By the end of 2010, a transiting Earth-mass planet in the habitability zone of a 600 Jupiter mass star (about the size of Lacaille 8760) would be confirmable on the basis of the transit
signature.

AVBursch wrote:

By the end of 2010, a transiting Earth-mass planet in the habitability zone of a 600 Jupiter mass star (about the size of Lacaille 8760) would be confirmable on the basis of the transit signature.

How do you propose that a planet can be confirmed based on only its transit light curve?
One of these isn't a planet... see if you can figure out which?

Five new exoplanets. 4 are larger than Jupiter. 1 is Neptune-sized. The relevant presentation just ended. 100 candidate planets in Kepler data so far. Thousands of candidate variable stars. Sub-stellar sized stars were expected to be prohibitively variable, but it didn't turn out to be that bad. Exoplanet sizes: 4 R_e, 15 R_e, 17 R_e, 19 R_e.

Kepler naming scheme.
4b, 5b, 6b 7b, 8b.
(3 planets alreay in field, so it's respect to those scientists).

Kepler-8 b Rossiter-McLaughlin effect measured. Prograde.
Kepler-4 b -> The Neptune.
Kepler-7 b very low density planet.

http://www.starstryder.com/2010/01/04/kepler-first-science/ We're told to expect something on arXiv.

http://www.sciencenews.org/view/generic/id/52465/title/Kepler_space_telescope_finds_its_first_extrasolar_planets
http://blogs.usatoday.com/sciencefair/2010/01/nasas-kepler-mission-finds-5-new-planets.html

"The Big Reveal"?

I think that headline is as hilarious as this bit of "CoRoT hype" nostalgia:

http://www.esa.int/SPECIALS/COROT/SEMF0C2MDAF_0.html

Surprises? What surprises?

At least the Kepler hype is happening at a faster pace than that of CoRoT.
It took the CoRoT team 12 months to hype a hot Jupiter with unusually
low density. The Kepler Team has managed this in only 10 months...

Putting the five planets in context with other known planets.
[img]http://www.nasa.gov/images/content/414914main_8_5_planet_discoveries.jpg[img]

Power point slides:
http://www.nasa.gov/mission_pages/kepler/multimedia/images/aas_conference.html

Press release:
http://www.nasa.gov/mission_pages/kepler/news/kepler-5-exoplanets.html

The data:
http://kepler.nasa.gov/Mission/discoveries/

Edit:
Fixed link - June 18, 2011.

Apparently this was extracted from just the first 43 days of data.

"Emphasis in 2010 will be on the discovery of small planet."

Look out for more Neptune's. As we know their rocky planet detection is delayed. Yaay.

I'm having a hard time suppressing my disappointment with the light curves released. I know some of these stars are variable and all, but is this the best the instrument can do after 8 months of processing.

Keep in mind Kepler was supposed to be very close, even out perform the Hubble spectrometer, due to longer iteration times.

Compare these curves with the Classic Hubble curve of HD209458b.




Right now the Kepler curve does not appear to be even close to the Hubble one.

Keep in mind that the Hubble curve is what we need to pick up Earth size transits.

The Earth signal would be less than ~ 5% of the 4 b signal.

Hopefully they can clean it up or else the bottom end of the survey might become increasingly incomplete.

My concern here is the current confirmation rate vs the expected number of detections as listed at http://kepler.nasa.gov/Science/KeplerScience/expectedResults/.

If we use 5 confirmations in 6 months as the average confirmation rate, then in one year we would expect to get about 10 confirmations. Now according to the link above, the number of expected Terrestrial inner-orbit exoplanets should be around 185 (the middle value of the three values listed). Assuming a steady confirmation rate of 10/yr, the process would take over 18 years! Note that this figure does not include the confirmation of any giant exoplanets.

Houston, we have a problem...

TheoA, you do realise that HD 209458 b is quite a bright star, right? HD 209458 has a visual magnitude of V = 7.65, and these Kepler stars have a visual magnitude of 12.6 - 13.9. You do realise that brighter stars like HD 209458 b allow for higher signal-to-noise ratios, right? These Kepler stars are on the order of 1/10,000 1/100 the brightness of HD 209458. I think Kepler is doing just fine.

Furthermore, the light curve you posted is in the Lyman alpha wavelength and is significantly deeper than the optical transit depth (which is where Kepler operates). I give you this graphic from this oklo post.

TheoA wrote:

Hopefully they can clean it up or else the bottom end of the survey might become increasingly incomplete.

I'm sure the CoRoT team isn't the only ones with the technical capacity to fold accumulated light curves. Remember how long it took them to announce CoRoT-7 b?

From a lowest-radius-planet standpoint, Kepler has already surpassed every other transit survey out there. With the first 48 days of data, it's already cranked out a confirmed Neptune. It took HATnet quite a while to accomplish this, and CoRoT was in Space for, what, a couple/3 years before CoRoT-7 b?

AlSchmitt wrote:

If we use 5 confirmations in 6 months as the average confirmation rate, then in one year we would expect to get about 10 confirmations. Now according to the link above, the number of expected Terrestrial inner-orbit exoplanets should be around 185 (the middle value of the three values listed). Assuming a steady confirmation rate of 10/yr, the process would take over 18 years! Note that this figure does not include the confirmation of any giant exoplanets.
Houston, we have a problem...

You've got to be kidding. You're basing the detection rate for on just this first announcement?

Furthermore, you do realise that radial-velocity confirmation is the bottleneck of planet-finding surveys. This is no fault of Houston.

Moderator hat: Enough with the "attack Kepler first, think about/investigate it later" style posts. Reasonable concerns are alright, but "why can't Kepler replicate pretty-as-HST light curves for stars that are 10,000 100 times dimmer?" style complaints are more than unreasonable.

Edit: Turns out, from the recent oklo post on the subject, that the Kepler stars are 1/100 the brightness of HD 209458, not 10,000 as I reasoned earlier.

Sirius_Alpha wrote:

AlSchmitt wrote:

If we use 5 confirmations in 6 months as the average confirmation rate, then in one year we would expect to get about 10 confirmations. Now according to the link above, the number of expected Terrestrial inner-orbit exoplanets should be around 185 (the middle value of the three values listed). Assuming a steady confirmation rate of 10/yr, the process would take over 18 years! Note that this figure does not include the confirmation of any giant exoplanets.
Houston, we have a problem...

You've got to be kidding. You're basing the detection rate for on just this first announcement?

Furthermore, you do realise that radial-velocity confirmation is the bottleneck of planet-finding surveys. This is no fault of Houston.

The detection rate was based on the only data point I had. I am well aware of the RV confirmation bottleneck. My comments were meant to highlight the fact that unless the process is facilitated in the future (e.g., additional confirmation facilities provided), the process could go on much longer than most people realiize.

Are we more likely to see transits of additional planets in 4b and 6b compared to the others?

Also, can the data for the "spotted" planet be taken out and the RV data used to fit additional trends.

Also, also, are there hints of transit timing variations in any of these?

tesh90, perhaps once the paper comes out (~3 hours, 30 minutes from now) we'll know more. But keep in mind that these five planets are only from the first 43 days of data. So transit timing variations may not be detected yet, but they may in the future, depending on what else is there.

tesh90 wrote:

Are we more likely to see transits of additional planets in 4b and 6b compared to the others?

Depends on whether or not such planets exist and if they are sufficiently inclined to allow transits. But I would think the odds are greater for any of the Kepler targets, since they are receiving near constant observation.

tesh90 wrote:

Also, can the data for the "spotted" planet be taken out and the RV data used to fit additional trends.

Take a look at the RV data. It's less than perfect.

Kepler-related papers have completely swamped today's ArXiv listing. It's amazing how much science it has done in only 43 days of observation! I didn't see the papers for Kepler-4 or Kepler-5.
_______________________________
Exoplanet Science:

A Transiting Hot Jupiter Orbiting a Metal-Rich Star
http://arxiv.org/abs/1001.0333

Kepler-7b: A Transiting Planet with Unusually Low Density
http://arxiv.org/abs/1001.0190


Discovery and Rossiter-McLaughlin Effect of Exoplanet Kepler-8b
http://arxiv.org/abs/1001.0416

The Discovery of Ellipsoidal Variations in the Kepler Light Curve of HAT-P-7
http://arxiv.org/abs/1001.0413


_______________________________
Asteroseismology, astrometry and astrophysics:

Preliminary Astrometric Results from Kepler
http://arxiv.org/abs/1001.0305

Asteroseismic Investigation of Known Planet Hosts in the Kepler Field
http://arxiv.org/abs/1001.0032

Solar-like oscillations in low-luminosity red giants: first results from Kepler
http://arxiv.org/abs/1001.0229

Kepler Asteroseismology Program: Introduction and First Results
http://arxiv.org/abs/1001.0139

Discovery of a red giant with solar-like oscillations in an eclipsing binary system from Kepler space-based photometry
http://arxiv.org/abs/1001.0399

Photometric Variability in Kepler Target Stars: The Sun Among Stars -- A First Look
http://arxiv.org/abs/1001.0414

First Kepler results on RR Lyrae stars
http://arxiv.org/abs/1001.0417

The asteroseismic potential of Kepler: first results for solar-type stars
http://arxiv.org/abs/1001.0506

Automated classification of variable stars in the asteroseismology program of the Kepler space mission
http://arxiv.org/abs/1001.0507


_______________________________
Kepler instrumentation and data handling:

Instrument Performance in Kepler's First Months
http://arxiv.org/abs/1001.0216

Initial Characteristics of Kepler Long Cadence Data For Detecting Transiting Planets
http://arxiv.org/abs/1001.0256

Overview of the Kepler Science Processing Pipeline
http://arxiv.org/abs/1001.0258

Kepler Mission Design, Realized Photometric Performance, and Early Science
http://arxiv.org/abs/1001.0268

The Kepler Pixel Response Function
http://arxiv.org/abs/1001.0331

The Kepler Follow-up Observation Program
http://arxiv.org/abs/1001.0352

Pre-Spectroscopic False Positive Elimination of Kepler Planet Candidates
http://arxiv.org/abs/1001.0392

Kepler Science Operations
http://arxiv.org/abs/1001.0437

Selection, Prioritization, and Characteristics of Kepler Target Stars
http://arxiv.org/abs/1001.0349



Furthermore, in the paper describing the ellipsoidal variation detection in HAT-P-7 b, it says

Quote :

In closing, the Kepler light of HAT-P-7 curve reveals ellipsoidal variations with an amplitude of approximately 37 ppm. This is the first detection of ellipsoidal variations in an exoplanet host star, and shows the precision Kepler is capable of producing even at this early stage. For comparison, a transit of an Earth-analog planet around a Sun-like star would produce a signal depth of 84 ppm, a factor of 2 larger than this effect.

http://oklo.org/2010/01/04/keplers-first-crop/

Quote :

According to a S&T editor Bob Naeye, who reported on Bill Borucki’s scientific talk this morning, the first 43 days of photometric observations from the satellite generated 175 transit candidates, of which 50 were followed up in detail to extract the 5 announced planets. The Keck I telescope has been the major workhorse for the high-precision RV follow-up efforts that are required to get accurate masses. According to the Keck I Telescope Schedule, 17 nights were allocated to the Kepler team from July through December of last year. Within this time alotment, roughly 50 RV measurements for the 5 new planets were obtained. The velocity precision for Kepler-4b looks to be of order 2-3 m/s, which is excellent.

Sirius_Alpha wrote:

With the magnitude difference, the Kepler stars
are 5 magnitudes dimmer, and a magnitude is 10 times the luminosity. So
these Kepler stars are on the order of 1/10,000 the brightness of HD
209458.

This is not correct. Vb~2.51. Though it does depend on the object and frequency being measured. Luminosity is not dependent on distance. Absolute Brightness is.

Also note Stars > M=12 saturate the Kepler detectors. The design + FOV + ~6 hour integration was chosen to just saturate the pixels (read reduce noise).

The instrument is not starved for photons. The only effect could come from the longer integrations.

Thanx for the posts Sirius.

Lots of fascinating info here. Finally some numbers to work with.

From below.

- The amplifier oscillation appears to be temperature dependent. Probably why they are having a hell of a time nailing it down.
- Other unexpected systematic artifacts are showing up.
- Full pixel well is 1.1 million electrons, with a gain ~ 112 e DN -1.
- The DAC is a 14 bit processor however allowing only 16384 DN positions. (This might be the essential difference with Hubble which had a 16 bit DAC allowing 65536 DN per pixel.)
- In practice this should not be a problem as the pixels just bleed into the neighbors along the pixel, except if, wait for it...
- There are systemic error signals.
- An earth transit signal is ~ 0.1 DN. For comfort they would want this to be 0.02 DN. Or roughly 2 electrons per DN. . That is simply amazing.
- ~ 85% of the FOV should get down to this level, though they are not be there yet. Which explains why that light curves look the way they do.
- The major one appears to be the temperature induced variation from the LDE to the FGS (Fine Guidance Sensor) clock cross talk.
- Their correction systems are under testing.
- Compression is loss less. Yay! Boo to COROT.

Also here's a picture of the guilty part. The LDE box. Coutesy of Ball Aerospace.



Here's a picture of the sensor array over the same box. You can see why getting there would be a problem.



[quote="Sirius_Alpha"]_______________________________
Kepler instrumentation and data handling:

Instrument Performance in Kepler's First Months
http://arxiv.org/abs/1001.0216

Initial Characteristics of Kepler Long Cadence Data For Detecting Transiting Planets
http://arxiv.org/abs/1001.0256

Overview of the Kepler Science Processing Pipeline
http://arxiv.org/abs/1001.0258

Kepler Mission Design, Realized Photometric Performance, and Early Science
http://arxiv.org/abs/1001.0268

The Kepler Pixel Response Function
http://arxiv.org/abs/1001.0331

[quote="Sirius_Alpha"]Furthermore, in the paper describing the ellipsoidal variation detection in HAT-P-7 b, it says

Quote :

In closing, the Kepler light of HAT-P-7 curve reveals ellipsoidal variations with an amplitude of approximately 37 ppm. This is the first detection of ellipsoidal variations in an exoplanet host star, and shows the precision Kepler is capable of producing even at this early stage. For comparison, a transit of an Earth-analog planet around a Sun-like star would produce a signal depth of 84 ppm, a factor of 2 larger than this effect.

Wasn't that particular one in manual mode.

Their paper says that they are still testing the system for Science mode.

Being conservative they want a signal 1/4 that of the Earth signal or 20 ppm.

Quote :

of which 50 were followed up in detail to extract the 5 announced planets.

Does that mean the other 45 were false positives. or are there more on the way?

TheoA wrote:

Does that mean the other 45 were false positives. or are there more on the way?

Good question. I wish I knew. I haven't read the plethora of papers that showed up on ArXiv today. I'll probably do that tomorrow. Maybe the answer lies in there somewhere.

Now Kepler has my respect! *lol*

But I wonder what's about Kepler-1,2 and 3???

I hoper they're upcoming

Edasich wrote:

But I wonder what's about Kepler-1,2 and 3???
I hoper they're upcoming

Sirius_Alpha wrote:

Kepler naming scheme.
4b, 5b, 6b 7b, 8b.
(3 planets alreay in field, so it's respect to those scientists).

http://kepler.nasa.gov/Mission/tableofdiscoveries/

Kepler-1 b -> TrES-2 b
Kepler-2 b -> HAT-P-7 b
Kepler-3 b -> HAT-P-11 b

The Kepler-5b paper from arxiv:

http://arxiv.org/abs/1001.0913

Quote :

Discovery of the Transiting Planet Kepler-5b

Authors: David G. Koch (NASA Ames Research Center), William J. Borucki (NASA Ames Research Center), Jason F. Rowe (NASA Ames Research Center), Natalie M. Batalha (San Jose State University), Timothy M. Brown (Las Cumbres Observatory Global Telescope), Douglas A. Caldwell (NASA Ames Research Center), John Caldwell (York University), William D. Cochran (University of Texas, Austin), Edna DeVore (SETI Institute), Edward W. Dunham (Lowell Observatory, Flagstaff), Andrea K. Dupree (Harvard-Smithsonian Center for Astrophysics), Thomas N. Gautier III (Jet Propulsion Laboratory), John C. Geary (Harvard-Smithsonian Center for Astrophysics), Ron L. Gilliland (Space Telescope Science Institute), Steve B. Howell (National Optical Astronomy Observatory), Jon M. Jenkins (SETI Institute), David W. Latham (Harvard-Smithsonian Center for Astrophysics),
Jack J. Lissauer (NASA Ames Research Center), Geoff W. Marcy (University of California, Berkeley), David Morrison (NASA Ames Research Center), Jill Tarter (SETI Institute)
et al. (4 additional authors not shown)
(Submitted on 6 Jan 2010)

Abstract: We present 44 days of high duty cycle, ultra precise photometry of the 13th magnitude star Kepler-5 (KIC 8191672, Teff=6300 K, logg=4.1), which exhibits periodic transits with a depth of 0.7%. Detailed modeling of the transit is consistent with a planetary companion with an orbital period of 3.548460+/-0.000032 days and a radius of 1.431+/-0.050 Rj. Follow-up radial velocity measurements with the Keck HIRES spectrograph on 9 separate nights demonstrate that the planet is more than twice as massive as Jupiter with a mass of 2.114+/-0.057 and a mean density of 0.894+/-0.079 g/cm^3.