Light Curves

We are in the process of making the KELT light curve data archive publicly available.  The mechanism for that is the NASA Exoplanet Archive (NEA) hosted by the NASA Exoplanet Science Institute (NExScI).  You can find about 1.1 million light curves already posted there, with time baselines of 1 to 2 years.  We are working to post many more during 2019.

The KELT data has some peculiarities that users should be aware of before using.  KELT observes a set of preselected fields across the sky.  The field locations are set for historical reasons.  Fields are observed with a cadence of about 20-30 minutes, with time baselines from 3 to 11 years, each clear night when above an airmass of 1.5.  The data are gathered over time, and the data reduced about once every two years, so a given lightcurve will typically end within the past 2 years, during which we have been accumulating more data.

The KELT pixels are 23 arcseconds across.  That means that blending with nearby stars can be considerable.  We obtain lightcurves for essentially everything in the field that is a known point source.  We are mostly complete in the range 8 < V < 13.  We do not currently have the ability to extract transient sources. 

The KELT telescopes have German Equatorial Mounts.  That means that depending whether they are pointing east or west of the meridian, the camera fields of view are flipped by 180 degrees.  So observations of a given field are taken in east or west orientation and need to be reduced separately.  Therefore, for each star observed, we have an east lightcurve and a west lightcurve, each with their own systematic noise properties, since the different orientations have different levels of blending and are taken at different time and airmass levels.

The east and west lightcurves are provided in two different flavors, raw and TFA.  Raw data are the direct products of the difference imaging pipeline  If you are looking for large amplitude periodic variation, like Cepheids or RR Lyrae, or punctuated variability at significant variation, like EBs or flares, we recommend using the raw data.  The typical RMS for the raw lightcurves is 1% to 3% for stars with 8 < V < 10. We also have a detrending procedure using the TFA algorithm from Kovács et al, which removes common trends to the data analogous to the Kepler CBVs.  That is better for looking for small-amplitude variability like Delta Scu and Gamma Dor pulsations, or transits. The typical RMS of TFA lightcurves is 0.5% to 1.5% for stars with 8 < V < 10.

For a given target, once can combine the east and west lightcurves to a combined version.  The procedure for that depends on whether one is using raw or TFA data, and the type of variability one is looking for.  Because the blending pattern in each orientation can be different, the amplitude of variation of the same star can be different in east and west, having been diluted by blending effects to different degrees.  We have some procedures that can partially correct for that, but they are not fully automated.

News

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New 'hot Jupiter' with short orbital period discovered

Jul 12

(Phys.org)—An international team of astronomers reports the discovery of a new "hot Jupiter" exoplanet with a short orbital period of just three and a half days. The newly detected giant planet, designated KELT-20b, circles a rapidly rotating star known as HD 185603 (or KELT-20). The finding was presented in a paper published July 5 on arXiv.org.

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Mysterious Stellar Eclipse Point To A Giant Ringed Gas Planet Surrounded By A Ring Of Dust

Jun 07

Scientists have discovered a giant ringed gas planet which is likely caused by a mysterious stellar eclipse. The planet has 50 times mass of Jupiter and it is surrounded by a ring of dust. According to researchers from the University of Warwick, this planet is hurtling around a star more than 1000 light years away from Earth.

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New 'hellish,' hot planet rivals most stars

Jun 06

Researchers recently discovered a strange, scorching-hot planet that is only slightly cooler than our sun.

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Major KELT-South Planet discovery

Apr 13

KELT-11b is the latest discovery from KELT-South. It is extraordinarily inflated, with a mass one fifth that of Jupiter but a size almost 40% larger, so the bulkdensity is below 0.1 grams per cc.

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