Results from the Exoplanet Search Programmes with BEST and TEST

Thueringer Landessternwarte Tautenburg (TLS) has started to operate a small dedicated telescope - the Tautenburg Exoplanet Search Telescope (TEST) - searching for transits of extrasolar planets in photometric time series observations. In a joint effort with the Berlin Exoplanet Search Telescope (BEST) operated by the Institut fuer Planetenforschung of the "Deutsches Zentrum fuer Luft- und Raumfahrt (DLR)" at the Observatoire de Haute-Provence (OHP), France, two observing sites are used to optimise transit search. Here, we give a short overview of these systems and the data analysis. We describe a software pipeline that we have set up to identify transit events of extrasolar planets and variable stars in time series data from these and other telescopes, and report on some first results.Comment: 6 pages, 5 figures, contributed paper to the "Solar and Stellar Physics Through Eclipses" conference, eds. O. Demircan, S.O. Selam, B. Albayrak (Turkey, March 2006

K2-60b and K2-107b. A Sub-Jovian and a Jovian Planet from the K2 Mission

We report the characterization and independent detection of K2-60b, as well as the detection and characterization of K2-107b, two transiting hot gaseous planets from the K2 space mission. We confirm the planetary nature of the two systems and determine their fundamental parameters combining the K2 time-series data with FIES @ NOT and HARPS-N @ TNG spectroscopic observations. K2-60b has a radius of 0.683 +/- 0.037 R-Jup and a mass of 0.426 +/- 0.037 M-Jup and orbits a G4 V star with an orbital period of 3.00267 +/- 0.00006 days. K2-107b has a radius of 1.44 +/- 0.15 R-Jup and a mass of 0.84 +/- 0.08 M-Jup and orbits an F9 IV star every 3.31392 +/- 0.00002 days. K2-60b is among the few planets at the edge of the so-called desert of short-period sub-Jovian planets. K2107b is a highly inflated Jovian planet orbiting an evolved star about to leave the main sequence

Greening of the brown-dwarf desert EPIC 212036875b: a 51 M-J object in a 5-day orbit around an F7V star

Context. Although more than 2000 brown dwarfs have been detected to date, mainly from direct imaging, their characterisation is difficult due to their faintness and model-dependent results. In the case of transiting brown dwarfs, however, it is possible to make direct high-precision observations. Aims. Our aim is to investigate the nature and formation of brown dwarfs by adding a new well-characterised object, in terms of its mass, radius and bulk density, to the currently small sample of less than 20 transiting brown dwarfs. Methods. One brown dwarf candidate was found by the KESPRINT consortium when searching for exoplanets in the K2 space mission Campaign 16 field. We combined the K2 photometric data with a series of multicolour photometric observations, imaging, and radial velocity measurements to rule out false positive scenarios and to determine the fundamental properties of the system. Results. We report the discovery and characterisation of a transiting brown dwarf in a 5.17-day eccentric orbit around the slightly evolved F7V star EPIC 212036875. We find a stellar mass of 1.15 +/- 0.08 M-circle dot, a stellar radius of 1.41 +/- 0.05 R-circle dot, and an age of 5.1 +/- 0.9 Gyr. The mass and radius of the companion brown dwarf are 51 +/- 2 M-J and 0.83 +/- 0.03 R-J, respectively, corresponding to a mean density of 108(-13)(+15) g cm(-3). Conclusions. EPIC 212036875 b is a rare object that resides in the brown-dwarf desert. In the mass-density diagram for planets, brown dwarfs, and stars, we find that all giant planets and brown dwarfs follow the same trend from similar to 0.3 M-J to the turn-over to hydrogen burning stars at similar to 73 M-J. EPIC 212036875 b falls close to the theoretical model for mature H/He dominated objects in this diagram as determined by interior structure models. We argue that EPIC 212036875 b formed via gravitational disc instabilities in the outer part of the disc, followed by a quick migration. Orbital tidal circularisation may have started early in its history for a brief period when the brown dwarf\u27s radius was larger. The lack of spin-orbit synchronisation points to a weak stellar dissipation parameter (Q(star)\u27 greater than or similar to 10(8)), which implies a circularisation timescale of greater than or similar to 23 Gyr, or suggests an interaction between the magnetic and tidal forces of the star and the brown dwarf

A transiting M-dwarf showing beaming effect in the field of Ruprecht 147

We report the discovery and characterization of an eclipsing M5Vdwarf star, orbiting a slightly evolved F7V main sequence star. In contrast to previous claims in the literature, we confirm that the system does not belong to the galactic open cluster Ruprecht 147. We determine its fundamental parameters combining K2 time-series data with spectroscopic observations from the McDonald Observatory, FIES@NOT, and HIRES@KECK. The very precise photometric data from the K2 mission allows us to measure variations caused by the beaming effect (relativistic doppler boosting), ellipsoidal variation, reflection, and the secondary eclipse. We determined the radial velocity using spectroscopic observations and compare it to the radial velocity determined from the beaming effect observed in the photometric data. The M5V star has a radius of 0.200(-0.008)(+0.007) R-circle dot and a mass of 0.187(-0.013)(+0.012) M-circle dot. The primary star has a radius of 1.518(-0.049)(+0.038) R-circle dot and a mass of 1.008(-0.097)(+0.081) M-circle dot. The orbital period is 5.441995 +/- 0.000007 d. The system is one of the few eclipsing systems with observed beaming effect and spectroscopic radial velocity measurements and it can be used as a test case for the modelling of the beaming effect. Current and forthcoming space missions such as TESS and PLATO might benefit from the analysis of the beaming effect to estimate the mass of transiting companions without the need for radial velocity follow up observations, provided that the systematic sources of noise affecting this method are well understood

The Next Generation Transit Survey (NGTS)

The Next Generation Transit Survey (NGTS) is a new ground-based sky survey designed to find transiting Neptunes and super-Earths. By covering at least sixteen times the sky area of Kepler, we will find small planets around stars that are sufficiently bright for radial velocity confirmation, mass determination and atmospheric characterisation. The NGTS instrument will consist of an array of twelve independently pointed 20 cm telescopes fitted with red-sensitive CCD cameras. It will be constructed at the ESO Paranal Observatory, thereby benefiting from the very best photometric conditions as well as follow up synergy with the VLT and E-ELT. Our design has been verified through the operation of two prototype instruments, demonstrating white noise characteristics to sub-mmag photometric precision. Detailed simulations show that about thirty bright super-Earths and up to two hundred Neptunes could be discovered. Our science operations are due to begin in 2014

K2-98b: A 32 M-circle plus NEPTUNE-SIZE PLANET IN A 10 DAY ORBIT TRANSITING AN F8 STAR

We report the discovery of K2-98b (EPIC 211391664b), a transiting Neptune-size planet monitored by the K2 mission during its Campaign 5. We combine the K2 time-series data with ground-based photometric and spectroscopic follow-up observations to confirm the planetary nature of the object and derive its mass, radius, and orbital parameters. K2-98b is a warm Neptune-like planet in a 10 day orbit around a V = 12.2 mag F-type star with M-star = 1.074 +/- 0.042 M-circle dot, R-star = 1.311(-0.048)(+0.083) R-circle dot, and age of 5.2(-1.0)(+1.2) Gyr We derive a planetary mass and radius of M-p = 32.2 +/- 8.1 M-circle plus and R-p = 4.3(-0.2)(+0.3) R-circle plus.K2-98b joins the relatively small group of Neptune-size planets whose mass and radius have been derived with a precision better than 25%. We estimate that the planet will be engulfed by its host star in similar to 3 Gyr, due to the evolution of the latter toward the red giant branch

Faisabilite de controle de production par camera video couplee a un micro-systeme informatique de prise de decision

CNRS AR 12150 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc

44 Validated Planets from K2 Campaign 10

We present 44 validated planets from the 10th observing campaign of the NASA K2 mission, as well as highresolution spectroscopy and speckle imaging follow-up observations. These 44 planets come from an initial set of 72 vetted candidates, which we subjected to a validation process incorporating pixel-level analyses, light curve analyses, observational constraints, and statistical false positive probabilities. Our validated planet sample has median values of R-p = 2.2 R-circle plus, P-orb = 6.9 days, T-eq = 890 K, and J = 11.2 mag. Of particular interest are four ultrashort period planets (P-orb less than or similar to 1 day), 16 planets smaller than 2 R-circle plus, and two planets with large predicted amplitude atmospheric transmission features orbiting infrared-bright stars. We also present 27 planet candidates, most of which are likely to be real and worthy of further observations. Our validated planet sample includes 24 new discoveries and has enhanced the number of currently known super-Earths (R-p approximate to 1-2R(circle plus)), sub-Neptunes (R-p approximate to 2-4R(circle plus)), and subSaturns (R-p approximate to 4-8R(circle plus)) orbiting bright stars (J = 8-10 mag) by similar to 4%, similar to 17%, and similar to 11%, respectively

K2-264: a transiting multiplanet system in the Praesepe open cluster

Planet host stars with well-constrained ages provide a rare window to the time domain of planet formation and evolution. The NASA K2 mission has enabled the discovery of the vast majority of known planets transiting stars in clusters, providing a valuable sample of planets with known ages and radii. We present the discovery of two planets transiting K2-264, an M2 dwarf in the intermediate age (600-800 Myr) Praesepe open cluster (also known as the Beehive Cluster, M44, or NGC 2632), which was observed by K2 during Campaign 16. The planets have orbital periods of 5.8 and 19.7 d, and radii of 2.2 +/- 0.2 and 2.7 +/- 0.2R(circle plus), respectively, and their equilibrium temperatures are 496 +/- 10 and 331 +/- 7 K, making this a system of two warm sub-Neptunes. When placed in the context of known planets orbiting field stars of similar mass to K2-264, these planets do not appear to have significantly inflated radii, as has previously been noted for some cluster planets. As the second known system of multiple planets transiting a star in a cluster, K2-264 should be valuable for testing theories of photoevaporation in systems of multiple planets. Follow-up observations with current near-infrared (NIR) spectrographs could yield planet mass measurements, which would provide information about the mean densities and compositions of small planets soon after photoevaporation is expected to have finished. Follow-up NIR transit observations using Spitzer or large ground-based telescopes could yield improved radius estimates, further enhancing the characterization of these interesting planets

Unmasking the hidden NGTS-3Ab: a hot Jupiter in an unresolved binary system

We present the discovery of NGTS-3Ab, a hot Jupiter found transiting the primary star of an unresolved binary system. We develop a joint analysis of multi-colour photometry, centroids, radial velocity (RV) cross-correlation function (CCF) profiles and their bisector inverse slopes (BIS) to disentangle this three-body system. Data from the Next Generation Transit Survey (NGTS), SPECULOOS and HARPS are analysed and modelled with our new blendfitter software. We find that the binary consists of NGTS-3A (G6V-dwarf) and NGTS-3B (K1V-dwarf) at <1 arcsec separation. NGTS-3Ab orbits every P = 1.675 days. The planet radius and mass are R_planet = 1.48+-0.37 R_J and M_planet = 2.38+-0.26 M_J, suggesting it is potentially inflated. We emphasise that only combining all the information from multi-colour photometry, centroids and RV CCF profiles can resolve systems like NGTS-3. Such systems cannot be disentangled from single-colour photometry and RV measurements alone. Importantly, the presence of a BIS correlation indicates a blend scenario, but is not sufficient to determine which star is orbited by the third body. Moreover, even if no BIS correlation is detected, a blend scenario cannot be ruled out without further information. The choice of methodology for calculating the BIS can influence the measured significance of its correlation. The presented findings are crucial to consider for wide-field transit surveys, which require wide CCD pixels (>5 arcsec) and are prone to contamination by blended objects. With TESS on the horizon, it is pivotal for the candidate vetting to incorporate all available follow-up information from multi-colour photometry and RV CCF profiles