We present the discovery of KELT-1b, the first transiting low-mass companion from the wide-field Kilodegree Extremely Little Telescope-North (KELT-North) transit survey. A joint analysis of the ...spectroscopic, radial velocity, and photometric data indicates that the V = 10.7 primary is a mildly evolved mid-F star with T sub(eff) = 6516+ or -49 K, log g = 4.228 super(+0.014) sub(-0.021) , and Fe/H = 0.052+ or -0.079, with an inferred mass M sub(*) = 1.335 + or - 0.063 M sub(middot in circle) and radius R sub(*) = 1.471 super(+0.045) sub(0.035) R sub(middot in circle). The companion is a low-mass brown dwarf or a super-massive planet with mass M sub(p) = 27.38 + or - 0.93 M sub(Jup) and radius R sub(p) = 1.116 super(+0.038) sub(-0.029) R sub(Jup). Comparison with standard evolutionary models suggests that the radius of KELT-1b is likely to be significantly inflated. Adaptive optics imaging reveals a candidate stellar companion to KELT-1 with a separation of 588 + or - 1 mas, which is consistent with an M dwarf if it is at the same distance as the primary.
We report on the design and first year of operations of the DEdicated MONitor of EXotransits and Transients (DEMONEXT). DEMONEXT is a 20-inch (0.5-m) robotic telescope using a PlaneWave CDK20 ...telescope on a Mathis instruments MI-750/1000 fork mount. DEMONEXT is equipped with a 2048 × 2048 pixel Finger Lakes Instruments (FLI) detector; a 10-position filter wheel with an electronic focuser and B, V, R, and I, g ′ , r ′ , i ′ , z ′ ; and clear filters. DEMONEXT operates in a continuous observing mode and achieves 2-4 mmag raw, unbinned, precision on bright V < 13 targets with 20-120 second exposures, and 1 mmag precision achieved by binning on 5-6 minute timescales. DEMONEXT maintains sub-pixel ( < 0.5 pixels) target position stability on the CCD over 8 hours in good observing conditions, with degraded performance in poor weather ( < 1 pixel). DEMONEXT achieves 1%-10% photometry on single-epoch targets with V < 17 in 5 minute exposures, with detection thresholds of V 21 . The DEMONEXT automated software has produced 143 planetary candidate transit light curves for the KELT collaboration and 48 supernovae and transient light curves for the ASAS-SN supernovae group in the first year of operation. DEMONEXT has also observed for a number of ancillary science projects including Galactic microlensing, active galactic nuclei, stellar variability, and stellar rotation.
The Kilodegree Extremely Little Telescope (KELT) project is a survey for planetary transits of bright stars. It consists of a small‐aperture, wide‐field automated telescope located at Winer ...Observatory near Sonoita, Arizona. The telescope surveys a set of 26° × 26° fields that together cover about 25% of the northern sky, and targets stars in the range of
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mag, searching for transits by close‐in Jupiters. This paper describes the system hardware and software and discusses the quality of the observations. We show that KELT is able to achieve the necessary photometric precision to detect planetary transits around solar‐type main‐sequence stars.
ABSTRACT We report the discovery of KELT-7b, a transiting hot Jupiter with a mass of MJ, radius of RJ, and an orbital period of days. The bright host star (HD 33643; KELT-7) is an F-star with V = ...8.54, Teff = 6789 K, Fe/H , and . It has a mass of M , a radius of R , and is the fifth most massive, fifth hottest, and the ninth brightest star known to host a transiting planet. It is also the brightest star around which Kilodegree Extremely Little Telescope (KELT) has discovered a transiting planet. Thus, KELT-7b is an ideal target for detailed characterization given its relatively low surface gravity, high equilibrium temperature, and bright host star. The rapid rotation of the star ( km s−1) results in a Rossiter-McLaughlin effect with an unusually large amplitude of several hundred m s−1. We find that the orbit normal of the planet is likely to be well-aligned with the stellar spin axis, with a projected spin-orbit alignment of λ = 9 7 5 2. This is currently the second most rapidly rotating star to have a reflex signal (and thus mass determination) due to a planetary companion measured.
ABSTRACT We report the discovery of KELT-4Ab, an inflated, transiting Hot Jupiter orbiting the brightest component of a hierarchical triple stellar system. The host star is an F star with = K, = , = ..., = , and = . The best-fit linear ephemeris is . With a magnitude of V ∼ 10, a planetary radius of , and a mass of , it is the brightest host among the population of inflated Hot Jupiters (RP > 1.5RJ), making it a valuable discovery for probing the nature of inflated planets. In addition, its existence within a hierarchical triple and its proximity to Earth (210 pc) provide a unique opportunity for dynamical studies with continued monitoring with high resolution imaging and precision radial velocities. The projected separation between KELT-4A and KELT-4BC is 328 16 AU and the projected separation between KELT-4B and KELT-4C is 10.30 0.74 AU. Assuming face-on, circular orbits, their respective periods would be 3780 290 and 29.4 3.6 years and the astrometric motions relative to the epoch in this work of both the binary stars around each other and of the binary around the primary star would be detectable now and may provide meaningful constraints on the dynamics of the system.
We report the discovery of KELT-3b, a moderately inflated transiting hot Jupiter with a mass of 1.477 super(+0.066) sub(-0.067) M sub(J), radius of 1.345 + or - 0.072 R sub(J), and an orbital period ...of 2.7033904 + or - 0.000010 days. The host star, KELT-3, is a V = 9.8 late F star with M sub(*) - 1.278 super(+0.063) sub(-0.061) , M sub(middot in circle), R sub(*) - 1.472 super(+0.065) sub(-0.067) R sub(middot in circle), T sub(eff) = 6306 super(+50) sub(-49) K, log(g) = 4.209 super(0.033) sub(0.031), and Fe/H = 0.044 super(+0.080) sub(-0.082) , and has a likely proper motion companion. KELT-3b is the third transiting exoplanet discovered by the KELT survey, and is orbiting one of the 20 brightest known transiting planet host stars, making it a promising candidate for detailed characterization studies. Although we infer that KELT-3 is significantly evolved, a preliminary analysis of the stellar and orbital evolution of the system suggests that the planet has likely always received a level of incident flux above the empirically identified threshold for radius inflation suggested by Demory & Seager.
We report on the design and first year of operations of the DEdicated MONitor of EXotransits and Transients (DEMONEXT). DEMONEXT is a 20-inch (0.5-m) robotic telescope using a PlaneWave CDK20 ...telescope on a Mathis instruments MI-750/1000 fork mount. DEMONEXT is equipped with a 2048 × 2048 pixel Finger Lakes Instruments (FLI) detector; a 10-position filter wheel with an electronic focuser and B, V, R, and I, g′, r′, i′, z′; and clear filters. DEMONEXT operates in a continuous observing mode and achieves 2-4 mmag raw, unbinned, precision on bright V < 13 targets with 20–120 second exposures, and 1 mmag precision achieved by binning on 5–6 minute timescales. DEMONEXT maintains sub-pixel (<0.5 pixels) target position stability on the CCD over 8 hours in good observing conditions, with degraded performance in poor weather (<1 pixel). DEMONEXT achieves 1%–10% photometry on single-epoch targets with V < 17 in 5 minute exposures, with detection thresholds of V ≈ 21. The DEMONEXT automated software has produced 143 planetary candidate transit light curves for the KELT collaboration and 48 supernovae and transient light curves for the ASAS-SN supernovae group in the first year of operation. DEMONEXT has also observed for a number of ancillary science projects including Galactic microlensing, active galactic nuclei, stellar variability, and stellar rotation.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted) We report the discovery of KELT-2Ab, a hot Jupiter transiting the bright (V = 8.77) primary star of the HD 42176 binary system. The ...host is a slightly evolved late F-star likely in the very short-lived "blue-hook" stage of evolution, with T sub(eff) = 6148 + or - 48 K, log g = ... and Fe/H = 0.034 + or - 0.78. The inferred stellar mass is Mlow * = ... and the star has a relatively large radius of Rlow * = ... The planet is a typical hot Jupiter with period 4.1137913 + or - 0.00001 days and a mass of M sub(P) = 1.524 + or - 0.088 M sub(J) and radius of R sub(P) = ... This is mildly inflated as compared to models of irradiated giant planets at the ~4 Gyr age of the system. KELT-2A is the third brightest star with a transiting planet identified by ground-based transit surveys, and the ninth brightest star overall with a transiting planet. KELT-2Ab's mass and radius are unique among the subset of planets with V < 9 host stars, and therefore increases the diversity of bright benchmark systems. We also measure the relative motion of KELT-2A and -2B over a baseline of 38 years, robustly demonstrating for the first time that the stars are bound. This allows us to infer that KELT-2B is an early K dwarf. We hypothesize that through the eccentric Kozai mechanism KELT-2B may have emplaced KELT-2Ab in its current orbit. This scenario is potentially testable with Rossiter-McLaughlin measurements, which should have an amplitude of ~44 m s super(-1).
We announce the discovery of KELT-16b, a highly irradiated, ultra-short period hot Jupiter transiting the relatively bright (visual magnitude equals 11.7) star TYC 2688-1839-1/KELT-16. A global ...analysis of the system shows KELT-16 to be an F7V star with effective temperature equal to 6236 plus or minus 54 degrees Kelvin, log g (sub asterisk) equal to 4.253 from plus 0.031 to minus 0.036, Fe/H equal to minus 0.002 from plus 0.086 to minus 0.085, mass (sub asterisk) equal to 1.211 from plus 0.043 to minus 0.046 times the solar mass, and radius (sub asterisk) equal to 1.360 from plus 0.064 o minus 0.053 times the solar radius. The planet is a relatively high-mass inflated gas giant with planetary mass equal to 2.75 from plus 0.016 to minus 0.15 times Jupiter's mass, planetary radius equal to 1.415 from plus 0.084 to minus 0.067 times Jupiter's radius, density planetary rho equal to 1.20 plus or minus 0.18 grams per cubic centimeter, surface gravity, log planetary gravity equal to 3.530 from plus 0.042 to minus 0.049, and equatorial temperature equal to 2453 from plus 55 to minus 47 degrees Kelvin. The best-fitting linear ephemeris is T(sub C) equal to 22457247.24791 plus or minus 0.00019 BJD (sub TDB) and P equal to 0.9689951 plus or minus 0.0000024 day. KELT-16b joins WASP-18b, -19b, -43b, -103b, and HATS-18b as the only giant transiting planets with periodicity P less than 1 day. Its ultra-short period and high irradiation make it a benchmark target for atmospheric studies by the Hubble Space Telescope, Spitzer, and eventually the James Webb Space Telescope. For example, as a hotter, higher-mass analog of WASP-43b, KELT-16b may feature an atmospheric temperature-pressure inversion and day-to-night temperature swing extreme enough for TiO to rain out at the terminator. KELT-16b could also join WASP-43b in extending tests of the observed mass-metallicity relation of the solar system gas giants to higher masses. KELT-16b currently orbits at a mere approximately 1.7 Roche radii from its host star, and could be tidally disrupted in as little as a few times 10 (sup 5) years (for a stellar tidal quality factor of Q (sup prime) (sub asterisk) equal to 10 (sup 5). Finally, the likely existence of a widely separated bound stellar companion in the KELT-16 system makes it possible that Kozai-Lidov (KL) oscillations played a role in driving KELT-16b inward to its current precarious orbit.
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