NGTS-14Ab: a Neptune-sized transiting planet in the desert
astro-ph.EP
/ Authors
A. M. S. Smith, J. S. Acton, D. R. Anderson, D. J. Armstrong, D. Bayliss, C. Belardi, F. Bouchy, R. Brahm, J. T. Briegal, E. M. Bryant
and 28 more authors
M. R. Burleigh, J. Cabrera, A. Chaushev, B. F. Cooke, J. C. Costes, Sz. Csizmadia, Ph. Eigmüller, A. Erikson, S. Gill, E. Gillen, M. R. Goad, M. N. Günther, B. A. Henderson, A. Hogan, A. Jordán, M. Lendl, J. McCormac, M. Moyano, L. D. Nielsen, H. Rauer, L. Raynard, R. H. Tilbrook, O. Turner, S. Udry
/ Abstract
Context: The sub-Jovian or Neptunian desert is a previously-identified region of parameter space where there is a relative dearth of intermediate-mass planets at short orbital periods. Aims: We present the discovery of a new transiting planetary system within the Neptunian desert, NGTS-14. Methods: Transits of NGTS-14Ab were discovered in photometry from the Next Generation Transit Survey (NGTS). Follow-up transit photometry was conducted from several ground-based facilities, as well as extracted from TESS full-frame images. We combine radial velocities from the HARPS spectrograph with the photometry in a global analysis to determine the system parameters. Results: NGTS-14Ab has a radius about 30 per cent larger than that of Neptune ($0.444\pm0.030~\mathrm{R_{Jup}}$), and is around 70 per cent more massive than Neptune ($0.092 \pm 0.012~\mathrm{M_{Jup}}$). It transits the main-sequence K1 star, NGTS-14A, with a period of 3.54 days, just far enough to have maintained at least some of its primordial atmosphere. We have also identified a possible long-period stellar mass companion to the system, NGTS-14B, and we investigate the binarity of exoplanet host stars inside and outside the Neptunian desert using Gaia.