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Post Info TOPIC: Kepler mission


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Title: Planetary Candidates from the First Year of the K2 Mission
Author: Andrew Vanderburg, David W. Latham, Lars A. Buchhave, Allyson Bieryla, Perry Berlind, Michael L. Calkins, Gilbert A. Esquerdo, Sophie Welsh, John Asher Johnson

The Kepler Space Telescope is currently searching for planets transiting stars along the ecliptic plane as part of its extended K2 mission. We processed the publicly released data from the first year of K2 observations (Campaigns 0, 1, 2, and 3) and searched for periodic eclipse signals consistent with planetary transits. Out of 59,174 targets we searched, we detect 234 planetary candidates around 208 stars. These candidates range in size from gas giants to smaller than the Earth, and range in orbital periods from hours to over a month. We conducted initial reconnaissance spectroscopy of 68 of the brighter candidate host stars, and present high resolution optical spectra for these stars. We make all of our data products, including light curves, spectra, and vetting diagnostics available to users online.

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Kepler telescope bags huge haul of planets

The science team sifting data from Nasa's Kepler space telescope says it has identified 715 new planets beyond our Solar System.
This is a huge new haul.
In the nearly two decades since the first so-called exoplanet was first discovered, researchers had claimed the detection of just over 1,000 new worlds.

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Title: Analysis of selected Kepler Mission planetary light curves
Author: M. D. Rhodes, E. Budding

We have modified the graphical user interfaced close binary system analysis program CurveFit to the form WinKepler and applied it to 16 representative planetary candidate light curves found in the NASA Exoplanet Archive (NEA) at the Caltech website this http URL, with an aim to compare different analytical approaches. WinKepler has parameter options for a realistic physical model, including gravity-brightening and structural parameters derived from the relevant Radau equation. We tested our best-fitting parameter-sets for formal determinacy and adequacy.
A primary aim is to compare our parameters with those listed in the NEA. Although there are trends of agreement, small differences in the main parameter values are found in some cases, and there may be some relative bias towards a 90 degrees value for the NEA inclinations. These are assessed against realistic error estimates.
Photometric variability from causes other than planetary transits affects at least 6 of the data-sets studied; with small pulsational behaviour found in 3 of those. For the false positive KOI 4.01, we found that the eclipses could be modelled by a faint background classical Algol as effectively as by a transiting exoplanet. Our empirical checks of limb-darkening, in the cases of KOI 1.01 and 12.01, revealed that the assigned stellar temperatures are probably incorrect. For KOI 13.01, our empirical mass-ratio differs by about 7% from that of Mislis and Hodgkin (2012), who neglected structural effects and higher order terms in the tidal distortion. Such detailed parameter evaluation, additional to the usual main geometric ones, provides an additional objective for this work.

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Nasa's Kepler telescope hobbled by faulty wheel

The planet-hunting space telescope Kepler has been hobbled by a broken wheel, say scientists at Nasa.
Two of four reaction wheels are now faulty. At least three are needed to orient the telescope correctly.
 
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The planet-hunting career of NASA's Kepler spacecraft might be near its end.
Astronomers said Wednesday that a reaction wheel that keeps the orbiting telescope pointed at tiny, distant patches of sky to look for Earth-like planets, has failed. If they can't fix it, Kepler will be relegated to a less prestigious mission, directing its gaze much closer to home in a search for so-called "near-Earth objects", i.e., meteors and asteroids.

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NASA's Kepler Wraps Prime Mission, Begins Extension

NASA is marking two milestones in the search for planets like Earth; the successful completion of the Kepler Space Telescope's three-and-a-half-year prime mission and the beginning of an extended mission that could last as long as four years.
Scientists have used Kepler data to identify more than 2,300 planet candidates and confirm more than 100 planets. Kepler is teaching us that the galaxy is teeming with planetary systems and that planets are prolific, and is giving us hints that nature makes small planets efficiently.

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Title: Objects in Kepler's Mirror May be Larger Than They Appear: Bias and Selection Effects in Transiting Planet Surveys
Authors: Eric Gaidos, Andrew W. Mann

Statistical analyses of large surveys for transiting planets such as the Kepler mission must account for systematic errors and biases. Transit detection depends not only on the planet's radius and orbital period, but also on host star properties. Thus, a sample of stars with transiting planets may not accurately represent the target population. Moreover, targets are selected using criteria such as a limiting apparent magnitude. These selection effects, combined with uncertainties in stellar radius, lead to biases in the properties of transiting planets and their host stars. We quantify possible biases in the Kepler survey. First, Eddington bias produced by a steep planet radius distribution and uncertainties in stellar radius results in a 15-20% overestimate of planet occurrence. Second, the magnitude limit of the Kepler target catalogue induces Malmquist bias towards large, more luminous stars and underestimation of the radii of about one third of candidate planets, especially those larger than Neptune. Third, because metal-poor stars are smaller, stars with detected planets will be very slightly (<0.02 dex) more metal-poor than the target average. Fourth, uncertainties in stellar radii produce correlated errors in planet radius and stellar irradiation. A previous finding, that highly-irradiated giant are more likely to have "inflated" radii, remains significant, even accounting for this effect. In contrast, transit depth is negatively correlated with stellar metallicity even in the absence of any intrinsic correlation, and a previous claim of a negative correlation between giant planet transit depth and stellar metallicity is probably an artifact.

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Kepler Data
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Additional Kepler Data Now Available to All Planet Hunters

As of Oct. 28, 2012, every observation from the extrasolar planet survey made by Kepler since its launch in 2009 through June 27, 2012, is available to scientists and the public.
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RE: Kepler mission
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Kepler glitch may lower odds of finding Earth's twin

Our chances of finding an Earthlike planet any time soon may have just shrunk due to a glitch that could limit the lifetime of NASA's exoplanet-hunting spacecraft Kepler.
On 16 July, Kepler sent down data showing that one of its four reaction wheels, whose spin controls the probe's orientation, had stopped turning. Ground controllers shut down the malfunctioning wheel and briefly stopped gathering scientific data.

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  NASA's Kepler Mission Awarded Mission Extension
 
NASA's Kepler mission has been approved for extension through fiscal year 2016 based on a recommendation from the Agency's Senior Review of its operating missions.. The extension provides four additional years to find Earth-size planets in the habitable zone -- the region in a planetary system where liquid water could exist on the surface of an orbiting planet around sun-like stars in our galaxy.
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