NGTS-39 b: A 58 d transiting warm Jupiter in an eccentric orbit
Abstract
We report the discovery and characterisation of NGTS-39 b (TIC 453147896 b), a warm Jupiter transiting a Sun-like star on a 58.2 day, eccentric (e = 0.386 +/- 0.019) orbit. NGTS-39 b was first identified from a TESS single-transit event, and subsequently confirmed with NGTS photometry and radial-velocity measurements from CORALIE and HARPS. The host star is a bright (Tmag = 11.02) F9 dwarf with an effective temperature of Teff = 6053 +67/-30 K. NGTS-39 b is a Jupiter-sized gas giant with a radius of 1.088 +/- 0.012 RJ and a mass of 1.467 +/- 0.081 MJ. Its equilibrium temperature is 519 +6/-5 K, placing it between short-period hot Jupiters and cold, Jupiter-like giants. The high orbital eccentricity and intermediate equilibrium temperature of NGTS-39 b make it a valuable test case for formation and migration models, particularly in the poorly sampled regime of long-period gas giants. The RV data show a linear trend of gamma dot = -17.75 m s^-1 yr^-1, which indicates the presence of an outer companion. The discovery of NGTS-39 b contributes to the small but growing population of transiting warm Jupiters with P > 50 days orbiting bright stars.
Cite
@article{arxiv.2607.02061,
title = {NGTS-39 b: A 58 d transiting warm Jupiter in an eccentric orbit},
author = {Ioannis Apergis and Daniel Bayliss and Solène Ulmer-Moll and Samuel Gill and Toby Rodel and Matthew Battley and Paul Benni and Allyson Bieryla and James A. Blake and Andrea Bonfanti and François Bouchy and Edward M. Bryant and Matthew R. Burleigh and Samuel J. Carlier and Sarah L. Casewell and Hritam Chakraborty and Alastair B. Claringbold and Karen A. Collins and Benjamin D. R. Davies and Xavier Dumusque and Troy A. Edkins and Fintan Eeles-Nolle and Jo Ann Egger and Jorge Fernández Fernández and Marcelo Aron Fetzner Keniger and Pedro Figueira and Michael R. Goad and George Harvey and Faith Hawthorn and Melissa J. Hobson and Mathilde Houelle and Giovanni Isopi and Timour Jestin and Alicia Kendall and Monika Lendl and Daniel Lewis and Isobel Lockley and Franco Mallia and James McCormac and Morgan A. Mitchell and Lucile Mignon and Hugh Osborn and Angelica Psaridi and Alex Romanec and Suman Saha and Amber Sedgley and Sérgio Sousa and Neil Thomas and Stéphane Udry and Christopher Watson and Richard G. West and Thomas G. Wilson and Peter J. Wheatley and Jamie T. Williams and Aldo Zapparata and Krzysztof Sz. Zieliński},
journal= {arXiv preprint arXiv:2607.02061},
year = {2026}
}
Comments
16 pages, 11 figures, Accepted in Monthly Notices of the Royal Astronomical Society