Kepler News and Results (Thread 2)

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Re: Kepler News and Results (Thread 2)

Post by Led_Zep on 15th May 2013, 4:13 pm

IS KEPLER DEAD ???
Sad

KEPLER mission manager update :
http://www.nasa.gov/mission_pages/kepler/news/keplerm-20130515.html
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Re: Kepler News and Results (Thread 2)

Post by jyril on 15th May 2013, 4:29 pm

From the release:

With the failure of a second reaction wheel, it's unlikely that the spacecraft will be able to return to the high pointing accuracy that enables its high-precision photometry. However, no decision has been made to end data collection.

While completely expected, this came much sooner than hoped. Sad

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Re: Kepler News and Results (Thread 2)

Post by Daniel on 15th May 2013, 4:36 pm

indeed a sad day for a great mission,and with cut of NASA budget turn new exoplanets missions far from come out of the papers so soon Sad
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Re: Kepler News and Results (Thread 2)

Post by Lazarus on 15th May 2013, 5:24 pm

Dynamics of Cats
http://scienceblogs.com/catdynamics/2013/05/15/kepler-the-little-spacecraft-that-could/

That is the end of Kepler’s primary science mission.
The data is in the archives available for analysis. There will be no more.
It is just short of finding the other Earth.
So very very close..

Sad
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Re: Kepler News and Results (Thread 2)

Post by Edasich on 16th May 2013, 4:28 am

Lazarus wrote:???

I just sorted by last updated in descending order, they're there.

Maybe you need to refresh your browser cache.

Today I see them in the list. You were right. Smile
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Re: Kepler News and Results (Thread 2)

Post by Galzi on 16th May 2013, 12:04 pm

Lazarus wrote:Dynamics of Cats
http://scienceblogs.com/catdynamics/2013/05/15/kepler-the-little-spacecraft-that-could/

That is the end of Kepler’s primary science mission.
The data is in the archives available for analysis. There will be no more.
It is just short of finding the other Earth.
So very very close..

Sad

Very sad, suffering failure when the holy Grail of Earth-like planets started to be within reach.
In addition, there isn't a Kepler 2 equivalent planned anytime soon. TESS is a very different kind of mission, PLATO is not yet selected to start.
Aside from high precision RV minimum mass planets, the search for another Earth for the time to come will be reduced to data-digging in the Kepler archive.

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Re: Kepler News and Results (Thread 2)

Post by pochimax on 16th May 2013, 3:08 pm

Galzi wrote:the search for another Earth for the time to come will be reduced to data-digging in the Kepler archive.
I hope It will be enough, especially if we were lucky and the earth-twin is in a brilliant K dwarf.

They are talking about an "hybrid mode" in which they use 2 reaction wheels and thrusters...

Or it might be to scan in a drift mode, observing with less modules to get faster downloads...

In both cases the photometry will not be good enough for small planets, but it could be good for the big ones.
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Re: Kepler News and Results (Thread 2)

Post by Lazarus on 16th May 2013, 4:26 pm

Optical Phase Curves of Kepler Exoplanets
http://arxiv.org/abs/1305.3271

Systems with secondary eclipses and phase curves, allowing determination of albedos and temperatures.

KOI-64 and KOI-2133 are false-positives, probably blends.
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Re: Kepler News and Results (Thread 2)

Post by Daniel on 17th May 2013, 2:42 am

pochimax wrote: In both cases the photometry will not be good enough for small planets, but it could be good for the big ones.

What about M dwarfs planets? for this stars have small size maybe is good for detection of small planets in M dwarf HZ in a new field out of the Cygnus constellation,Just a thought...
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Re: Kepler News and Results (Thread 2)

Post by Edasich on 17th May 2013, 2:43 am

A new KOI with confirmed planet:

KOI-127b: a very low-albedo, Saturn-mass transiting planet around a metal rich solar-like star

We report the discovery of KOI-127b, a Saturn-mass transiting planet in a 3.6-day orbit around a metal-rich solar-like star. We combined the publicly available Kepler photometry (quarters 1-13) with high-resolution spectroscopy from the Sandiford@McDonald and FIES@NOT spectrographs. We derived the system parameters via a simultaneous joint fit to the photometric and radial velocity measurements. Our analysis is based on the Bayesian approach and is carried out by sampling the parameter posterior distributions using Markov chain Monte Carlo simulation. KOI-127b is a moderately inflated planet with a mass of Mp=0.430+/-0.032 Mjup, radius of Rp=0.960+/-0.016 Rjup, and bulk density of 0.603+/-0.055 g/cm^3. It orbits a slowly rotating (P=36+/-6 days) G5V star with M*=0.95+/-0.04 Msun, R*=0.99+/-0.02 Rsun, Teff=5520+/-60 K, [M/H]=0.20+/-0.05, and an age of 7.5+/-2.0 Gyr. The lack of detectable planetary occultation with a depth larger than about 10 ppm, implies a planet's geometric and Bond albedo of Ag<0.087+/-0.008 and Ab<0.058+/-0.006, respectively, placing KOI-127b among the gas-giant planets with the lowest albedo known so far. We found neither additional planetary transit signals, nor transit timing variations (TTVs) at a level of about 0.5 minutes, in accordance with the trend that close-in gas giant planets seem to belong to single-planet systems. The 106 transits observed in short-cadence mode by Kepler for nearly 1.2 years show no detectable signatures of the planet's passage in front of starspots. We explored the implications of the absence of detectable spot-crossing events for the inclination of the stellar spin-axis, the sky-projected spin-orbit obliquity, and the latitude of magnetically active regions.
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Re: Kepler News and Results (Thread 2)

Post by Led_Zep on 17th May 2013, 6:00 am

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Re: Kepler News and Results (Thread 2)

Post by Led_Zep on 22nd May 2013, 9:25 am

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Re: Kepler News and Results (Thread 2)

Post by Lazarus on 28th May 2013, 2:25 pm

Exoplanets in the Post-Kepler Era

Program is now online, including videos and PDFs. Some interesting things about masses of Kepler candidates and the transition between rocky and volatile-rich planets.
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Re: Kepler News and Results (Thread 2)

Post by Shellface on 28th May 2013, 4:37 pm

Oh man. Marcy's pdf isn't so much of a sneak peek into a currently unpublished paper, but a show of it. And a great show; that's most of the inventory of well characterised low-mass planets right there, with a few non-transiters and trends to boot. And think what could be done when you take that photometry to brighter stars! TESS will be amazing, for certain.

Rather unrelated-ly, Mayor's pdf is a look into what's going on with HARPS. The ten stars of the really super ultra high precision sample are looking good, with the half of them being identified low-mass planet hosts being indicative of the real scale of the population in the galaxy. I wonder how Zeta Tucanae and Delta Pavonis are looking? Especially since the latter is Fe/H = 0.3.… Meanwhile, the results from the high precision metal-poor sample are also looking promising - the velocity curves on show look like neptunes, which is interesting in light of the metallicity-unbiased population of small planets from Kepler. Now, the major question is - are those thick disk or halo stars? The planets of the latter population is not yet understood.

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Re: Kepler News and Results (Thread 2)

Post by Sirius_Alpha on 28th May 2013, 8:27 pm

Adaptive Optics Images II: 12 Kepler Objects of Interest and 15 Confirmed Transiting Planets

http://arxiv.org/abs/1305.6548

Edit:
KOI-174 b is a 1.94 R_e planet with a T_eql of 331 K (reference). If you want to consider Kepler-22b a habitable planet candidate, you may as well include KOI-174 b. Table 1 refers to a KOI-973 and KOI-979, but I think these may be typos... if so they should be KOI-1973 and KOI-1979.

They seem to list KOI-283.01 as having a mass that is fairly reasonable, but the KOI database I linked earlier has it listed as a false positive. Neutral

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Re: Kepler News and Results (Thread 2)

Post by Led_Zep on 30th May 2013, 7:58 pm

http://www.skyandtelescope.com/news/Exoplanet-Studies-After-Kepler-Whats-next-209400371.html

« ….Marcy, who called himself devastated when the news broke two weeks ago, was still in mourning. “With the likely demise of Kepler, our ability to measure the occurrence of Earth analogs is compromised,” he said. “We needed two or three more years [of data] to definitively measure it.”
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Re: Kepler News and Results (Thread 2)

Post by Sirius_Alpha on 1st June 2013, 1:32 am


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Re: Kepler News and Results (Thread 2)

Post by Led_Zep on 1st June 2013, 5:39 am

2740 + 1924 = 4664 KOI !!! Shocked Shocked
A lot of work for the coming years !!
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Re: Kepler News and Results (Thread 2)

Post by jyril on 1st June 2013, 5:57 am

I think this was discussed before, but d'oh!

MJ: In the Q1-Q12 data set there are a surprising number of KOIs with orbital periods near one Earth-year. Do Earth-size planets tend to prefer Earth-like periods?

MH: Excellent question. Remember that the Kepler spacecraft orbits the sun every 371 days. Given its extremely stable environment, some noise sources associated with the local detector electronics exhibit repetitive behavior with this periodicity. Since these electronics read-out the charge-coupled devices (CCDs), this noise is intertwined with the astronomical signals in such a way that the two are almost impossible to disentangle. Hence, this repetitive noise can mimic the signature of a transiting planet.

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Re: Kepler News and Results (Thread 2)

Post by Led_Zep on 1st June 2013, 11:40 am

More and more difficult to understand : pale

MJ: With previous Kepler data releases, the term 'KOI' was synonymous with planet candidate. Can you explain what has changed?

MH: This is a common misperception. Actually, the definition of KOI has not changed; but our reporting philosophy has. In the past, the Kepler mission published lists of KOIs that were deemed to be planet candidates; and separately posted the KOIs that were declared false positives at MAST (Mikulski Archive for Space Telescopes). This may have given some the mistaken impression that all KOIs are planet candidates, but this has never been the case. For example, four of the first ten KOIs identified using the first month of data are currently marked as false positives in the cumulative activity table at the NASA Exoplanet Archive.

The reporting philosophy has been modified so that all KOIs can be archived in one place. This makes it much easier to change the status of a KOI from ‘planet candidate’ to ‘false positive,’ and vice versa. In addition, the new format enables more rapid release of incremental information as progress is made
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Re: Kepler News and Results (Thread 2)

Post by Galzi on 2nd June 2013, 2:27 pm

Somewhat confusing press release. Apparently in this new KOI release the Kepler guys are relaxing some of the criteria needed for candidate status - accepting a larger % of false positive rather than losing some interesting low SNR transit-like signals. They are also resorting to eye inspection, hopeful this will partially stem the increase of false positive.

Since the extended mission lasted only 6 months instead of 3.5 years, this is the only road available for extracting the most tasting fruits of the Kepler harvest.

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Re: Kepler News and Results (Thread 2)

Post by Stalker on 3rd June 2013, 3:30 am

Lazarus wrote:Exoplanets in the Post-Kepler Era

Program is now online, including videos and PDFs. Some interesting things about masses of Kepler candidates and the transition between rocky and volatile-rich planets.

I have a problem with Marcy's pdf. I want to find the semi major axis from a/Rstar given in the pdf. For the first planet i find...~0.0002 AU, it's impossible with a period of 13 days! I cant find my mistake.

The stellar radius is converted in m (1.49->2 074 080 000), then a (in m) is converted to AU (1AU=149 597 870 700 m). What is the problem?

Third Kepler law give me 0.11 AU

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Re: Kepler News and Results (Thread 2)

Post by Lazarus on 3rd June 2013, 1:26 pm

I think the a/rstar column is the planet-to-star radius ratio, rather than the semimajor axis.

If it were semimajor axis, then a/rstar < 1 (which it is for all the listed KOIs) would imply the planet is inside the star...
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Re: Kepler News and Results (Thread 2)

Post by Stalker on 3rd June 2013, 1:28 pm

Oh, indeed.

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Re: Kepler News and Results (Thread 2)

Post by pochimax on 4th June 2013, 10:54 am

Led_Zep wrote:2740 + 1924 = 4664 KOI !!! Shocked Shocked
A lot of work for the coming years !!
¿only initially 2.740 KOIs? I think you are confused. KOIs are not equal to candidates. Nor now neither before.
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