Volume 612, April 2018
|Number of page(s)||11|
|Section||Planets and planetary systems|
|Published online||04 May 2018|
Dipartimento di Fisica, Università degli Studi di Torino,
via Pietro Giuria 1,
2 Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
3 Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08544, USA
4 Department of Astronomy, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan
5 Department of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, 439 92 Onsala, Sweden
6 Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
7 Astrobiology Center, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
8 National Astronomical Observatory of Japan, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
9 Institute of Planetary Research, German Aerospace Center, Rutherfordstrasse 2, 12489 Berlin, Germany
10 Departamento de Astrofísica, Universidad de La Laguna, 38206 Tenerife, Spain
11 Instituto de Astrofísica de Canarias, C/ Vía Láctea s/n, 38205 La Laguna, Tenerife, Spain
12 Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegrade 120, 8000 Aarhus C, Denmark
13 Department of Astronomy and McDonald Observatory, University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712, USA
14 Leiden Observatory, University of Leiden, PO Box 9513, 2300 RA Leiden, The Netherlands
15 Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Asakuchi, Okayama 719-0232, Japan
16 Rheinisches Institut für Umweltforschung, Abteilung Planetenforschung an der Universität zu Köln, Aachener Strasse 209, 50931 Köln, Germany
17 Thüringer Landessternwarte Tautenburg, Sternwarte 5, 07778 Tautenberg, Germany
18 Department of Astronomy, The Ohio State University, 140 West 18th Ave., Columbus, OH 43210, USA
19 Center for Astronomy and Astrophysics, TU Berlin, Hardenbergstr. 36, 10623 Berlin, Germany
Accepted: 11 January 2018
We report on the discovery of K2-141 b (EPIC 246393474 b), an ultra-short-period super-Earth on a 6.7 h orbit transiting an active K7 V star based on data from K2 campaign 12. We confirmed the planet’s existence and measured its mass with a series of follow-up observations: seeing-limited MuSCAT imaging, NESSI high-resolution speckle observations, and FIES and HARPS high-precision radial-velocity monitoring. K2-141 b has a mass of 5.31 ± 0.46 M⊕ and radius of 1.54−0.09+0.10 R⊕, yielding a mean density of 8.00−1.45+1.83 g cm−3 and suggesting a rocky-iron composition. Models indicate that iron cannot exceed ~70% of the total mass. With an orbital period of only 6.7 h, K2-141 b is the shortest-period planet known to date with a precisely determined mass.
Key words: planetary systems / planets and satellites: individual: EPIC 246393474 b / stars: fundamental parameters / stars: individual: EPIC 246393474 / techniques: photometric / techniques: radial velocities
Based on observations obtained with (a) the Nordic Optical Telescope (NOT), operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos (ORM) of the Instituto de Astrofisica de Canarias (IAC); (b) the 3.6m ESO telescope at La Silla Observatory under program ID 099.C-0491; (c) the Kepler space telescope in its extended mission K2.
Tables of the light curve data and the radial velocities are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (184.108.40.206) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/612/A95
© ESO 2018
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