Suchergebnisse

The Transiting Exoplanet Survey Satellite mission was designed to find transiting planets around bright, nearby stars. Here, we present the detection and mass measurement of a small, short-period (≈4 days) transiting planet around the bright (V=7.9), solar-type star HD 86226 (TOI-652, TIC 22221375), previously known to host a long-period (∼1600 days) giant planet. HD 86226c (TOI-652.01) has a radius of 2.16±0.08R⊕ and a mass of - 7.25+1.12 1.19 M⊕, based on archival and new radial velocity data. We also update the parameters of the longer-period, not-known-to-transit planet, and find it to be less eccentric and less massive than previously reported. The density of the transiting planet is 3.97 gcm−3, which is low enough to suggest that the planet has at least a small volatile envelope, but the mass fractions of rock, iron, and water are not well-constrained. Given the host star brightness, planet period, and location of the planet near both the "radius gap" and the "hot Neptune desert," HD 86226c is an interesting candidate for transmission spectroscopy to further refine its composition. ; NASA's Science Mission directorate NASA through Hubble Fellowship grant - Space Telescope Science Institute HST-HF2-51399.001 National Aeronautics & Space Administration (NASA) NAS5-26555 18-XRP18_2-0048 CONICYT-PFCHA/Doctorado Nacional, Chile 21140646 European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant 713673 "la Caixa" INPhINIT Fellowship grant LCF/BQ/IN17/11620033 European Research Council (ERC) 724427 Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) CONICYT FONDECYT 1161218 Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) Basal AFB-170002 Spanish Ministry of Economics and Competitiveness PGC2018-098153-B-C31 Heising-Simons Foundation Swiss National Science Foundation (SNSF) European Commission 200020_172746 National Aeronautics & Space Administration (NASA)

We report the period, eccentricity, and mass determination for the Transiting Exoplanet Survey Satellite (TESS) single-transit event candidate TOI-222, which displayed a single 3000 ppm transit in the TESS 2-min cadence data from Sector 2. We determine the orbital period via radial velocity measurements (P = 33.9 d), which allowed for ground-based photometric detection of two subsequent transits. Our data show that the companion to TOI-222 is a low-mass star, with a radius of 0.18(-0.10)(+0.39) R-circle dot and a mass of 0.23 +/- 0.01 M-circle dot. This discovery showcases the ability to efficiently discover long-period systems from TESS single-transit events using a combination of radial velocity monitoring coupled with high-precision ground-based photometry. ; Swiss National Science Foundation (SNSF) Geneva University Swiss National Science Foundation (SNSF) Science & Technology Facilities Council (STFC) ST/M001962/1 ST/S002642/1 Science & Technology Facilities Council (STFC) ST/L000733/1 ST/P000495/1 ST/N000757/1 ST/P000312/1 1226157 STFC via an Ernest Rutherford Fellowship ST/R00384X/1 MIT's Kavli Institute Austrian Research Promotion Agency (FFG) 859724 Comisión Nacional de Investigación Científica y Tecnológica (CONICYT) PB06 CONICYT-PFCHA, Chile 21191829 Millennium Institute of Astrophysics (MAS) Comisión Nacional de Investigación Científica y Tecnológica (CONICYT) CONICYT FONDECYT 1161218 3180246 1171208 Ministry for the Economy, Development, and Tourism's Programa Iniciativa Científica Milenio IC120009 European Research Council (ERC) 681601 ERC under the European Union 320964 Australian Research Council LE160100001 DP180100972 Mount Cuba Astronomical Foundation University of Texas at Austin UNSW Australia MIT Nanjing University George Mason University University of Louisville University of California System University of Florida NASA's Science Mission directorate University of Southern Queensland