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

S. Dreizler, I. J.M. Crossfield, D. Kossakowski, P. Plavchan, S. V. Jeffers, J. Kemmer, R. Luque, N. Espinoza, E. Pallé, K. Stassun, E. Matthews, B. Cale, J. A. Caballero, M. Schlecker, J. Lillo-Box, M. Zechmeister, S. Lalitha, A. Reiners, A. Soubkiou, B. BitschM. R. Zapatero Osorio, P. Chaturvedi, A. P. Hatzes, G. Ricker, R. Vanderspek, D. W. Latham, S. Seager, J. Winn, J. M. Jenkins, J. Aceituno, P. J. Amado, K. Barkaoui, M. Barbieri, N. M. Batalha, F. F. Bauer, B. Benneke, Z. Benkhaldoun, C. Beichman, J. Berberian, J. Burt, R. P. Butler, D. A. Caldwell, A. Chintada, A. Chontos, J. L. Christiansen, D. R. Ciardi, C. Cifuentes, K. A. Collins, K. I. Collins, D. Combs, M. Cortés-Contreras, J. D. Crane, T. Daylan, D. Dragomir, E. Esparza-Borges, P. Evans, F. Feng, E. E. Flowers, A. Fukui, B. Fulton, E. Furlan, E. Gaidos, C. Geneser, S. Giacalone, M. Gillon, E. Gonzales, V. Gorjian, C. Hellier, D. Hidalgo, A. W. Howard, S. Howell, D. Huber, H. Isaacson, E. Jehin, E. L.N. Jensen, A. Kaminski, S. R. Kane, K. Kawauchi, J. F. Kielkopf, H. Klahr, M. R. Kosiarek, L. Kreidberg, M. Kürster, M. Lafarga, J. Livingston, D. Louie, A. Mann, A. Madrigal-Aguado, R. A. Matson, T. Mocnik, J. C. Morales, P. S. Muirhead, F. Murgas, S. Nandakumar, N. Narita, G. Nowak, M. Oshagh, H. Parviainen, V. M. Passegger, D. Pollacco, F. J. Pozuelos, A. Quirrenbach, M. Reefe, I. Ribas, P. Robertson, C. Rodríguez-López, M. E. Rose, A. Roy, A. Schweitzer, J. Schlieder, S. Shectman, A. Tanner, H. V. Senavcl, J. Teske, J. D. Twicken, J. Villasenor, S. X. Wang, L. M. Weiss, J. Wittrock, M. Yllmaz, F. Zohrabi

Research output: Contribution to journalArticlepeer-review

Abstract

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.

Original languageEnglish (US)
Article numberA127
JournalAstronomy and Astrophysics
Volume644
DOIs
StatePublished - Dec 1 2020

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Methods: data analysis
  • Planetary systems
  • Planets and satellites: individual: LP 714-47 b
  • Stars: individual: LP 714-47
  • Stars: late-type

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