Lightcurves

We are in the process of making the KELT lightcurve 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 lightcurves already posted there, with time baselines of 1 to 2 years.  We are working to post many more during 2019.

The KELT data have 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 to three years, so a given lightcurve on disk 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 the telescope is pointing east or west of the meridian, the camera field of view is 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 times 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 variations, like Cepheids or RR Lyrae, or punctuated variability at significant amplitude, 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, one 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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KELT Transit Search to conclude after 17 years of work

Mar 09

After 14 years of observations, 17 years since the project conception, 26 planets discovered, and dozens of papers, the KELT transit search is ending. This transition has been long-expected, since the NASA TESS mission has revolutionized the discovery of transiting exoplanets. We will continue observations by both KELT telescopes for as long as practical, since there is so much more science to be done outside of transit discovery. Thank you to everyone who supported the KELT project!

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KELT website receives Award of Distinction at the 25th Annual Communicator Awards

Jun 07

We are honored to have received the Award of Distinction at the 25th Annual Communicator Awards from the Academy of Interactive and Visual Arts for this website, together with our web design partners at 3twenty9 Design, LLC.

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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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