A Second Planet Transiting LTT 1445A and a Determination of the Masses of Both Worlds
Author:
Winters Jennifer G.ORCID, Cloutier RyanORCID, Medina Amber A.ORCID, Irwin Jonathan M., Charbonneau DavidORCID, Astudillo-Defru NicolaORCID, Bonfils Xavier, Howard Andrew W.ORCID, Isaacson HowardORCID, Bean Jacob L.ORCID, Seifahrt AndreasORCID, Teske Johanna K., Eastman Jason D.ORCID, Twicken Joseph D.ORCID, Collins Karen A.ORCID, Jensen Eric L. N.ORCID, Quinn Samuel N.ORCID, Payne Matthew J.ORCID, Kristiansen Martti H.ORCID, Spencer Alton, Vanderburg AndrewORCID, Zechmeister MathiasORCID, Weiss Lauren M.ORCID, Wang Sharon XuesongORCID, Wang GavinORCID, Udry StéphaneORCID, Terentev Ivan A.ORCID, Stürmer JulianORCID, Stefánsson GudmundurORCID, Shporer AviORCID, Shectman StephenORCID, Sefako RamotholoORCID, Schwengeler Hans MartinORCID, Schwarz Richard P.ORCID, Scarsdale NicholasORCID, Rubenzahl Ryan A.ORCID, Roy ArpitaORCID, Rosenthal Lee J., Robertson PaulORCID, Petigura Erik A.ORCID, Pepe Francesco, Omohundro Mark, Murphy Joseph M. AkanaORCID, Murgas FelipeORCID, Močnik TeoORCID, Montet Benjamin T.ORCID, Mennickent RonaldORCID, Mayo Andrew W.ORCID, Massey BobORCID, Lubin JackORCID, Lovis Christophe, Lewin PabloORCID, Kasper DavidORCID, Kane Stephen R.ORCID, Jenkins Jon M.ORCID, Huber DanielORCID, Horne KeithORCID, Hill Michelle L.ORCID, Gorrini PaulaORCID, Giacalone StevenORCID, Fulton BenjaminORCID, Forveille ThierryORCID, Figueira Pedro, Fetherolf TaraORCID, Dressing CourtneyORCID, Díaz Rodrigo F.ORCID, Delfosse XavierORCID, Dalba Paul A.ORCID, Dai FeiORCID, Cortés C. C., Crossfield Ian J. M., Crane Jeffrey D.ORCID, Conti Dennis M.ORCID, Collins Kevin I.ORCID, Chontos AshleyORCID, Butler R. PaulORCID, Brown PeytonORCID, Brady Madison, Behmard AidaORCID, Beard CoreyORCID, Batalha Natalie M.ORCID, Almenara Jose-ManuelORCID
Abstract
Abstract
LTT 1445 is a hierarchical triple M-dwarf star system located at a distance of 6.86 pc. The primary star LTT 1445A (0.257 M
⊙) is known to host the transiting planet LTT 1445Ab with an orbital period of 5.36 days, making it the second-closest known transiting exoplanet system, and the closest one for which the host is an M dwarf. Using Transiting Exoplanet Survey Satellite data, we present the discovery of a second planet in the LTT 1445 system, with an orbital period of 3.12 days. We combine radial-velocity measurements obtained from the five spectrographs, Echelle Spectrograph for Rocky Exoplanets and Stable Spectroscopic Observations, High Accuracy Radial Velocity Planet Searcher, High-Resolution Echelle Spectrometer, MAROON-X, and Planet Finder Spectrograph to establish that the new world also orbits LTT 1445A. We determine the mass and radius of LTT 1445Ab to be 2.87 ± 0.25 M
⊕ and
1.304
−
0.060
+
0.067
R
⊕, consistent with an Earth-like composition. For the newly discovered LTT 1445Ac, we measure a mass of
1.54
−
0.19
+
0.20
M
⊕ and a minimum radius of 1.15 R
⊕, but we cannot determine the radius directly as the signal-to-noise ratio of our light curve permits both grazing and nongrazing configurations. Using MEarth photometry and ground-based spectroscopy, we establish that star C (0.161 M
⊙) is likely the source of the 1.4 day rotation period, and star B (0.215 M
⊙) has a likely rotation period of 6.7 days. We estimate a probable rotation period of 85 days for LTT 1445A. Thus, this triple M-dwarf system appears to be in a special evolutionary stage where the most massive M dwarf has spun down, the intermediate mass M dwarf is in the process of spinning down, while the least massive stellar component has not yet begun to spin down.
Publisher
American Astronomical Society
Subject
Space and Planetary Science,Astronomy and Astrophysics
Cited by
28 articles.
订阅此论文施引文献
订阅此论文施引文献，注册后可以免费订阅5篇论文的施引文献，订阅后可以查看论文全部施引文献
|
|