Variability Properties of Four Million Sources in the TESS Input Catalog Observed with the Kilodegree Extremely Little Telescope Survey

The Kilodegree Extremely Little Telescope (KELT) has been surveying more than 70% of the celestial sphere for nearly a decade. While the primary science goal of the survey is the discovery of transiting, large-radii planets around bright host stars, the survey has collected more than 106 images, with a typical cadence between 10–30 minutes, for more than four million sources with apparent visual magnitudes in the approximate range . Here, we provide a catalog of 52,741 objects showing significant large-amplitude fluctuations likely caused by stellar variability, as well as 62,229 objects identified with likely stellar rotation periods. The detected variability ranges in rms-amplitude from ∼3 mmag to ∼2.3 mag, and the detected periods range from ∼0.1 to ≳2000 days. We provide variability upper limits for all other ∼4,000,000 sources. These upper limits are principally a function of stellar brightness, but we achieve typical 1σ sensitivity on 30 min timescales down to ∼5 mmag at , and down to ∼43 mmag at . We have matched our catalog to the TESS Input catalog and the AAVSO Variable Star Index to precipitate the follow-up and classification of each source. The catalog is maintained as a living database on the Filtergraph visualization portal at the URL https://filtergraph.com/kelt_vars.

[1]  Eduardo Serrano,et al.  LSST: From Science Drivers to Reference Design and Anticipated Data Products , 2008, The Astrophysical Journal.

[2]  K. Sokolovsky,et al.  Machine learning search for variable stars , 2017, 1710.07290.

[3]  Joseph E. Rodriguez,et al.  Identification of young stellar variables with KELT for K2 – II. The Upper Scorpius association , 2017, 1707.07313.

[4]  Keivan G. Stassun,et al.  The TESS Input Catalog and Candidate Target List , 2017, The Astronomical Journal.

[5]  J. Vanderplas.  Understanding the Lomb–Scargle Periodogram , 2017, 1703.09824.

[6]  Keivan G. Stassun,et al.  KELT-19Ab: A P ∼ 4.6-day Hot Jupiter Transiting a Likely Am Star with a Distant Stellar Companion , 2017, 1709.07010.

[7]  Keivan G. Stassun,et al.  KELT-20b: A Giant Planet with a Period of P ∼ 3.5 days Transiting the V ∼ 7.6 Early A Star HD 185603 , 2017, 1707.01518.

[8]  Andrew Gould,et al.  A giant planet undergoing extreme-ultraviolet irradiation by its hot massive-star host , 2017, Nature.

[9]  R. G. West,et al.  WASP-167b/KELT-13b: Joint discovery of a hot Jupiter transiting a rapidly-rotating F1V star , 2017, 1704.07771.

[10]  Joseph E. Rodriguez,et al.  Identification of Young Stellar Variables with KELT for K2. I. Taurus Dippers and Rotators , 2017, 1703.02522.

[11]  M. Penny,et al.  KELT-18b: Puffy Planet, Hot Host, Probably Perturbed , 2017, 1702.01657.

[12]  Samson A. Johnson,et al.  The Mysterious Dimmings of the T Tauri Star V1334 Tau , 2017, 1701.03044.

[13]  M. Penny,et al.  KELT-12b: A P ∼ 5 day, Highly Inflated Hot Jupiter Transiting a Mildly Evolved Hot Star , 2016, 1608.04714.

[14]  Keivan G. Stassun,et al.  KELT-11b: A Highly Inflated Sub-Saturn Exoplanet Transiting the V = 8 Subgiant HD 93396 , 2016, 1607.01755.

[15]  N. N. Kireeva,et al.  General catalogue of variable stars: Version GCVS 5.1 , 2017 .

[16]  Keivan G. Stassun,et al.  Photometric Variability of the Be Star Population , 2016, 1609.08449.

[17]  Xu Zhou,et al.  STELLAR FLARES IN THE CSTAR FIELD: RESULTS FROM THE 2008 DATA SET , 2016, 1608.07904.

[18]  Henry Ngo,et al.  KELT-16b: A Highly Irradiated, Ultra-short Period Hot Jupiter Nearing Tidal Disruption , 2016, 1608.00618.

[19]  Nicolas A. Pereyra,et al.  GW150914: FIRST SEARCH FOR THE ELECTROMAGNETIC COUNTERPART OF A GRAVITATIONAL-WAVE EVENT BY THE TOROS COLLABORATION , 2016, 1607.07850.

[20]  Joseph E. Rodriguez,et al.  KELT-17B: A HOT-JUPITER TRANSITING AN A-STAR IN A MISALIGNED ORBIT DETECTED WITH DOPPLER TOMOGRAPHY , 2016, 1607.03512.

[21]  A Wide-Field Survey for Transiting Hot Jupiters and Eclipsing Pre-Main-Sequence Binaries in Young Stellar Associations , 2016, 1606.02993.

[22]  D. York,et al.  STELLAR VARIABILITY AND FLARE RATES FROM DOME A, ANTARCTICA, USING 2009 AND 2010 CSTAR OBSERVATIONS , 2016, 1603.09699.

[23]  Joseph E. Rodriguez,et al.  AN EXTREME ANALOGUE OF ϵ AURIGAE: AN M-GIANT ECLIPSED EVERY 69 YEARS BY A LARGE OPAQUE DISK SURROUNDING A SMALL HOT SOURCE , 2016, 1601.00135.

[24]  S. Lynn,et al.  Planet Hunters IX. KIC 8462852-where's the flux? , 2015, 1509.03622.

[25]  KELT-10b: the first transiting exoplanet from the KELT-South survey – a hot sub-Jupiter transiting a V = 10.7 early G-star , 2015, 1509.02323.

[26]  S. Metchev,et al.  Young Stars & Planets Near the Sun, , 2016 .

[27]  Keivan G. Stassun,et al.  KELT-4Ab: AN INFLATED HOT JUPITER TRANSITING THE BRIGHT (V ∼ 10) COMPONENT OF A HIERARCHICAL TRIPLE , 2015, 1510.00015.

[28]  Keivan G. Stassun,et al.  KELT-14b AND KELT-15b: AN INDEPENDENT DISCOVERY OF WASP-122b AND A NEW HOT JUPITER , 2015, 1509.08953.

[29]  Keivan G. Stassun,et al.  KELT-8b: A HIGHLY INFLATED TRANSITING HOT JUPITER AND A NEW TECHNIQUE FOR EXTRACTING HIGH-PRECISION RADIAL VELOCITIES FROM NOISY SPECTRA , 2015, 1505.06738.

[30]  Joseph E. Rodriguez,et al.  V409 TAU AS ANOTHER AA TAU: PHOTOMETRIC OBSERVATIONS OF STELLAR OCCULTATIONS BY THE CIRCUMSTELLAR DISK , 2015, 1505.05805.

[31]  D. Schneider,et al.  RAPID ROTATION OF LOW-MASS RED GIANTS USING APOKASC: A MEASURE OF INTERACTION RATES ON THE POST-MAIN-SEQUENCE , 2015, 1505.03536.

[32]  Keivan G. Stassun,et al.  KELT-7b: A HOT JUPITER TRANSITING A BRIGHT V = 8.54 RAPIDLY ROTATING F-STAR , 2015, The Astronomical Journal.

[33]  Richard G. Baraniuk,et al.  Estimating a Common Period for a Set of Irregularly Sampled Functions with Applications to Periodic Variable Star Data , 2014, 1412.6520.

[34]  Observations of the M82 SN 2014J with the Kilodegree Extremely Little Telescope , 2014, 1411.4150.

[35]  Russell Deitrick,et al.  KEPLER FLARES. I. ACTIVE AND INACTIVE M DWARFS , 2014, 1410.7779.

[36]  Huigen Yang,et al.  DIFFERENCE IMAGE ANALYSIS OF DEFOCUSED OBSERVATIONS WITH CSTAR , 2014, 1410.4544.

[37]  Keivan G. Stassun,et al.  KELT-6b: A P ∼ 7.9 DAY HOT SATURN TRANSITING A METAL-POOR STAR WITH A LONG-PERIOD COMPANION , 2013, 1308.2296.

[38]  Mark Clampin,et al.  Transiting Exoplanet Survey Satellite (TESS) , 2014, Astronomical Telescopes and Instrumentation.

[39]  J. Pepper,et al.  EVALUATING GYROCHRONOLOGY ON THE ZERO-AGE-MAIN-SEQUENCE: ROTATION PERIODS IN THE SOUTHERN OPEN CLUSTER BLANCO 1 FROM THE KELT-SOUTH SURVEY , 2013, 1312.3946.

[40]  J. Pepper,et al.  An observational correlation between stellar brightness variations and surface gravity , 2013, Nature.

[41]  M. Pinsonneault,et al.  FAST STAR, SLOW STAR; OLD STAR, YOUNG STAR: SUBGIANT ROTATION AS A POPULATION AND STELLAR PHYSICS DIAGNOSTIC , 2013, 1306.3701.

[42]  Joseph E. Rodriguez,et al.  OCCULTATION OF THE T TAURI STAR RW AURIGAE A BY ITS TIDALLY DISRUPTED DISK , 2013, 1308.2017.

[43]  Keivan G. Stassun,et al.  KELT-3b: A HOT JUPITER TRANSITING A V = 9.8 LATE-F STAR , 2012, 1211.1031.

[44]  P. Conroy,et al.  HATSouth: A Global Network of Fully Automated Identical Wide-Field Telescopes , 2012, 1206.1391.

[45]  Suresh Sivanandam,et al.  EXOPLANETS FROM THE ARCTIC: THE FIRST WIDE-FIELD SURVEY AT 80°N , 2012, 1211.1972.

[46]  J. Pepper,et al.  KELT-1b: A STRONGLY IRRADIATED, HIGHLY INFLATED, SHORT PERIOD, 27 JUPITER-MASS COMPANION TRANSITING A MID-F STAR , 2012, 1206.1635.

[47]  L. Hebb,et al.  KELT-2Ab: A HOT JUPITER TRANSITING THE BRIGHT (V = 8.77) PRIMARY STAR OF A BINARY SYSTEM , 2012, 1206.1592.

[48]  Keivan Stassun,et al.  The KELT-South Telescope , 2012, 1202.1826.

[49]  Keivan G. Stassun,et al.  TIME-SERIES PHOTOMETRY OF STARS IN AND AROUND THE LAGOON NEBULA. I. ROTATION PERIODS OF 290 LOW-MASS PRE-MAIN-SEQUENCE STARS IN NGC 6530 , 2011, 1112.2211.

[50]  Xu Zhou,et al.  PHOTOMETRY OF VARIABLE STARS FROM DOME A, ANTARCTICA , 2011, 1309.3325.

[51]  L. Walkowicz,et al.  PHOTOMETRIC VARIABILITY IN KEPLER TARGET STARS. II. AN OVERVIEW OF AMPLITUDE, PERIODICITY, AND ROTATION IN FIRST QUARTER DATA , 2010, 1008.1092.

[52]  Howard Isaacson,et al.  Kepler Planet-Detection Mission: Introduction and First Results , 2010, Science.

[53]  L. Moln'ar,et al.  The Konkoly Blazhko Survey: is light-curve modulation a common property of RRab stars? , 2009, 0908.1015.

[54]  J. Bochanski,et al.  M DWARFS IN SLOAN DIGITAL SKY SURVEY STRIPE 82: PHOTOMETRIC LIGHT CURVES AND FLARE RATE ANALYSIS , 2009, 0906.2030.

[55]  G. Pojmański,et al.  Galactic fundamental mode RR Lyrae stars. Period - amplitude diagram, metallicities and distribution , 2009, 0906.2199.

[56]  Andrzej Pigulski,et al.  β Cephei stars in the ASAS-3 data. II. 103 new β Cephei stars and a discussion of low-frequency modes , 2007, 0711.2530.

[57]  Richard W. Pogge,et al.  The Kilodegree Extremely Little Telescope (KELT): A Small Robotic Telescope for Large‐Area Synoptic Surveys , 2007, 0704.0460.

[58]  R. Poleski,et al.  All‐Sky Automated Survey eclipsing binaries with observed high period change rates , 2007, astro-ph/0703705.

[59]  B. Enoch,et al.  The WASP Project and the SuperWASP Cameras , 2006, astro-ph/0608454.

[60]  M. Skrutskie,et al.  The Two Micron All Sky Survey (2MASS) , 2006 .

[61]  Aaron D. Price,et al.  The AAVSO Comparison Star Database and the Automated Chart Plotter , 2006 .

[62]  B. A. McLeod,et al.  Pushing the Limits of Ground-based Photometric Precision: Submillimagnitude Time-Series Photometry of the Open Cluster NGC 6791 , 2005, astro-ph/0504487.

[63]  University of Michigan,et al.  Analysis of RR Lyrae Stars in the Northern Sky Variability Survey , 2006, astro-ph/0606092.

[64]  W. T. Vestrand,et al.  Identifying Red Variables in the Northern Sky Variability Survey , 2004 .

[65]  R. Noyes,et al.  A trend filtering algorithm for wide-field variability surveys , 2004, astro-ph/0411724.

[66]  Celso Grebogi,et al.  Integrated chaos-based communication , 2004 .

[67]  K. E. McGowan,et al.  Northern Sky Variability Survey: Public Data Release , 2004, astro-ph/0401217.

[68]  K. Stanek,et al.  Wide‐Field Millimagnitude Photometry with the HAT: A Tool for Extrasolar Planet Detection , 2004, astro-ph/0401219.

[69]  C. Alard.  Image subtraction using a space-varying kernel , 2000 .

[70]  Keivan G. Stassun,et al.  The Rotation Period Distribution of Pre-Main-Sequence Stars in and around the Orion Nebula , 1999 .

[71]  R. Lupton,et al.  A Method for Optimal Image Subtraction , 1997, astro-ph/9712287.

[72]  Peter B. Stetson,et al.  ON THE AUTOMATIC DETERMINATION OF LIGHT-CURVE PARAMETERS FOR CEPHEID VARIABLES , 1996 .

[73]  P. Stetson.  DAOPHOT: A COMPUTER PROGRAM FOR CROWDED-FIELD STELLAR PHOTOMETRY , 1987 .

[74]  J. Scargle.  Studies in astronomical time series analysis. II - Statistical aspects of spectral analysis of unevenly spaced data , 1982 .

[75]  N. Lomb.  Least-squares frequency analysis of unequally spaced data , 1976 .

[76]  Andrew T. Young,et al.  Photometric error analysis. VI. Confirmation of Reiger's theory of scintillation , 1967 .

[77]  R. P. Kraft,et al.  STUDIES OF STELLAR ROTATION. V. THE DEPENDENCE OF ROTATION ON AGE AMONG SOLAR-TYPE STARS. , 1967 .

[78]  S. Blažko.  Mitteilungen über veränderliche Sterne , 1907 .