TOI-269 b: An eccentric sub-Neptune transiting a M2 dwarf revisited with ExTrA
Abstract
We present the confirmation of a new sub-Neptune close to the transition between super-Earths and sub-Neptunes transiting the M2 dwarf TOI- 269 (TIC 220479565, V = 14.4 mag, J = 10.9 mag, Rstar = 0.40 Rsun, Mstar = 0.39 Msun, d = 57 pc). The exoplanet candidate has been identified in multiple TESS sectors, and validated with high-precision spectroscopy from HARPS and ground-based photometric follow-up from ExTrA and LCO-CTIO. We determined mass, radius, and bulk density of the exoplanet by jointly modeling both photometry and radial velocities with juliet. The transiting exoplanet has an orbital period of P = 3.6977104 +- 0.0000037 days, a radius of 2.77 +- 0.12 Rearth, and a mass of 8.8 +- 1.4 Mearth. Since TOI-269 b lies among the best targets of its category for atmospheric characterization, it would be interesting to probe the atmosphere of this exoplanet with transmission spectroscopy in order to compare it to other sub-Neptunes. With an eccentricity e = 0.425+0.082-0.086, TOI-269 b has one of the highest eccentricities of the exoplanets with periods less than 10 days. The star being likely a few Gyr old, this system does not appear to be dynamically young. We surmise TOI-269 b may have acquired its high eccentricity as it migrated inward through planet-planet interactions.
Keywords
Cite
@article{arxiv.2104.14782,
title = {TOI-269 b: An eccentric sub-Neptune transiting a M2 dwarf revisited with ExTrA},
author = {M. Cointepas and J. M. Almenara and X. Bonfils and F. Bouchy and N. Astudillo-Defru and F. Murgas and J. F. Otegi and A. Wyttenbach and D. R. Anderson and E. Artigau and B. L. Canto Martins and D. Charbonneau and K. A. Collins and K. I. Collins and J-J. Correia and S. Curaba and A. Delboulbe and X. Delfosse and R. F. Diaz and C. Dorn and R. Doyon and P. Feautrier and P. Figueira and T. Forveille and G. Gaisne and T. Gan and L. Gluck and R. Helled and C. Hellier and L. Jocou and P. Kern and S. Lafrasse and N. Law and I. C. Leao and C. Lovis and Y. Magnard and A. W. Mann and D. Maurel and J. R. de Medeiros and C. Melo and T. Moulin and F. Pepe and P. Rabou and S. Rochat and D. R. Rodriguez and A. Roux and N. C. Santos and D. Segransan and E. Stadler and E. B. Ting and J. D. Twicken and S. Udry and W. C. Waalkes and R. G. West and A. Wunsche and C. Ziegler and G. Ricker and R. Vanderspek and D. W. Latham and S. Seager and J. Winn and J. M. Jenkins},
journal= {arXiv preprint arXiv:2104.14782},
year = {2021}
}
Comments
23 pages, 16 figures, Accepted for publication in A&A