TESS and CHEOPS discover two warm sub-Neptunes transiting the bright K-dwarf HD 15906

A. Tuson, D. Queloz, H. P. Osborn, T. G. Wilson, M. J. Hooton, M. Beck, M. Lendl, G. Olofsson, A. Fortier, A. Bonfanti, A. Brandeker, L. A. Buchhave, A. Collier Cameron, D. R. Ciardi, K. A. Collins, D. Gandolfi, Z. Garai, S. Giacalone, J. Gomes da Silva, S. B. HowellJ. A. Patel, C. M. Persson, L. M. Serrano, S. G. Sousa, S. Ulmer-Moll, A. Vanderburg, C. Ziegler, Y. Alibert, R. Alonso, G. Anglada, T. Bárczy, D. Barrado Navascues, S. C.C. Barros, W. Baumjohann, T. Beck, W. Benz, N. Billot, X. Bonfils, L. Borsato, C. Broeg, J. Cabrera, S. Charnoz, D. M. Conti, Sz Csizmadia, P. E. Cubillos, M. B. Davies, M. Deleuil, L. Delrez, O. D.S. Demangeon, B. O. Demory, D. Dragomir, C. D. Dressing, D. Ehrenreich, A. Erikson, Z. Essack, J. Farinato, L. Fossati, M. Fridlund, E. Furlan, H. Gill, M. Gillon, C. L. Gnilka, E. Gonzales, M. Güdel, M. N. Günther, S. Hoyer, K. G. Isaak, J. M. Jenkins, L. L. Kiss, J. Laskar, D. W. Latham, N. Law, A. Lecavelier des Etangs, G. Lo Curto, C. Lovis, R. Luque, D. Magrin, A. W. Mann, P. F.L. Maxted, M. Mayor, S. McDermott, M. Mecina, C. Mordasini, A. Mortier, V. Nascimbeni, R. Ottensamer, I. Pagano, E. Pallé, G. Peter, G. Piotto, D. Pollacco, T. Pritchard, R. Ragazzoni, N. Rando, F. Ratti, H. Rauer, I. Ribas, G. R. Ricker, M. Rieder, N. C. Santos, A. B. Savel, G. Scandariato, R. P. Schwarz, S. Seager, D. Ségransan, A. Shporer, A. E. Simon, A. M.S. Smith, M. Steller, C. Stockdale, Gy M. Szabó, N. Thomas, G. Torres, R. Tronsgaard, S. Udry, B. Ulmer, V. Van Grootel, R. Vanderspek, J. Venturini, N. A. Walton, J. N. Winn, B. Wohler

Research output: Contribution to journalArticlepeer-review


Two warm sub-Neptunes have been discovered orbiting the bright K-dwarf star HD 15906. These planets were observed by the Transiting Exoplanet Survey Satellite (TESS). The inner planet, HD 15906 b, has a confirmed orbit, but the outer planet, HD 15906 c, had ambiguous data, requiring additional observations from the CHaracterising ExOPlanet Satellite (CHEOPS). Results show that HD 15906 b orbits every roughly 10.92 days and HD 15906 c every approximately 21.58 days. The temperatures of the planets are estimated to be 668 K and 532 K, respectively. This system is unique as it's one of only six known with two warm sub-Neptune planets orbiting a bright star and offers a prime opportunity for further study on planet composition and formation theories.
Original languageEnglish
Pages (from-to)3090-3118
Number of pages29
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
StatePublished - Aug 1 2023

ASJC Scopus Subject Areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • planets and satellites: detection
  • planets and satellites: fundamental parameters
  • stars: fundamental parameters
  • stars: individual: HD 15906 (TOI 461, TIC 4646810)
  • techniques: photometric

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