The CARMENES search for exoplanets around M dwarfs: LP 714-47 b (TOI 442.01): Populating the Neptune desert

Publication date: 
Main author: 
Dreizler S.
IAA authors: 
Aceituno, J.;Amado, P. J.;Bauer, F. F.
Dreizler, S.;Crossfield, I. J.M.;Kossakowski, D.;Plavchan, P.;Jeffers, S. V.;Kemmer, J.;Luque, R.;Espinoza, N.;Pallé, E.;Stassun, K.;Matthews, E.;Cale, B.;Caballero, J. A.;Schlecker, M.;Lillo-Box, J.;Zechmeister, M.;Lalitha, S.;Reiners, A.;Soubkiou, A.;Bitsch, B.;Zapatero Osorio, M. R.;Chaturvedi, P.;Hatzes, A. P.;Ricker, G.;Vanderspek, R.;Latham, D. W.;Seager, S.;Winn, J.;Jenkins, J. M.;Aceituno, J.;Amado, P. J.;Barkaoui, K.;Barbieri, M.;Batalha, N. M.;Bauer, F. F.;Benneke, B.;Benkhaldoun, Z.;Beichman, C.;Berberian, J.;Burt, J.;Butler, R. P.;Caldwell, D. A.;Chintada, A.;Chontos, A.;Christiansen, J. L.;Ciardi, D. R.;Cifuentes, C.;Collins, K. A.;Collins, K. I.;Combs, D.;Cortés-Contreras, M.;Crane, J. D.;Daylan, T.;Dragomir, D.;Esparza-Borges, E.;Evans, P.;Feng, F.;Flowers, E. E.;Fukui, A.;Fulton, B.;Furlan, E.;Gaidos, E.;Geneser, C.;Giacalone, S.;Gillon, M.;Gonzales, E.;Gorjian, V.;Hellier, C.;Hidalgo, D.;Howard, A. W.;Howell, S.;Huber, D.;Isaacson, H.;Jehin, E.;Jensen, E. L.N.;Kaminski, A.;Kane, S. R.;Kawauchi, K.;Kielkopf, J. F.;Klahr, H.;Kosiarek, M. R.;Kreidberg, L.;Kürster, M.;Lafarga, M.;Livingston, J.;Louie, D.;Mann, A.;Madrigal-Aguado, A.;Matson, R. A.;Mocnik, T.;Morales, J. C.;Muirhead, P. S.;Murgas, F.;Nandakumar, S.;Narita, N.;Nowak, G.;Oshagh, M.;Parviainen, H.;Passegger, V. M.;Pollacco, D.
Astronomy and Astrophysics
Publication type: 
© ESO 2020. We report the discovery of a Neptune-like planet (LP 714-47 b, P = 4.05204 d, mb = 30.8 ± 1.5Mpdbl, Rb = 4.7 ± 0.3 Rpdbl) located in the 'hot Neptune desert'. Confirmation of the TESS Object of Interest (TOI 442.01) was achieved with radial-velocity follow-up using CARMENES, ESPRESSO, HIRES, iSHELL, and PFS, as well as from photometric data using TESS, Spitzer, and ground-based photometry from MuSCAT2, TRAPPIST-South, MONET-South, the George Mason University telescope, the Las Cumbres Observatory Global Telescope network, the El Sauce telescope, the TÜBITAK National Observatory, the University of Louisville Manner Telescope, and WASP-South. We also present high-spatial resolution adaptive optics imaging with the Gemini Near-Infrared Imager. The low uncertainties in the mass and radius determination place LP 714-47 b among physically well-characterised planets, allowing for a meaningful comparison with planet structure models. The host star LP 714-47 is a slowly rotating early M dwarf (Teff = 3950 ± 51 K) with a mass of 0.59 ± 0.02Mpdbl and a radius of 0.58 ± 0.02Rpdbl. From long-term photometric monitoring and spectroscopic activity indicators, we determine a stellar rotation period of about 33 d. The stellar activity is also manifested as correlated noise in the radial-velocity data. In the power spectrum of the radial-velocity data, we detect a second signal with a period of 16 days in addition to the four-day signal of the planet. This could be shown to be a harmonic of the stellar rotation period or the signal of a second planet. It may be possible to tell the difference once more TESS data and radial-velocity data are obtained.
ADS Bibcode: 
Methods: data analysis | Planetary systems | Planets and satellites: individual: LP 714-47 b | Stars: individual: LP 714-47 | Stars: late-type