Planetary system around LTT 1445A unveiled by ESPRESSO: Multiple planets in a triple M-dwarf system star,star star

• Type: Article in International Scientific Journal
• Date: 2023

Authors

Lavie, B (Author) Other; Bouchy, F (Author) Other; Lovis, C (Author) Other; Osorio, MZ (Author) Other; Deline, A (Author) Other; Barros, S (Author) Other; Figueira, P (Author) Other; Sozzetti, A (Author) Other; Hernandez, JIG (Author) Other; Lillo-Box, J (Author) Other; Rodrigues, J (Author) Other; Mehner, A (Author) Other; Damasso, M (Author) Other; Adibekyan, V (Author) Other; Alibert, Y (Author) Other; Prieto, CA (Author) Other; Cristiani, S (Author) Other; D'Odorico, V (Author) Other; Di Marcantonio, P (Author) Other; Ehrenreich, D (Author) Other; Santos, RG (Author) Other; Lo Curto, G (Author) Other; Martins, CJAP (Author) FCUP; Micela, G (Author) Other; Molaro, P (Author) Other; Nunes, N (Author) Other; Palle, E (Author) Other; Pepe, F (Author) Other; Poretti, E (Author) Other; Rebolo, R (Author) Other; N.C. Santos (Author) FCUP; Sousa, SG (Author) FCUP; Mascareno, AS (Author) Other; Tabrenero, H (Author) Other; Udry, S (Author) Other

Journal

Title: Astronomy and Astrophysics

Vol. 673

Final page: A69

ISSN: 0004-6361

Publisher: EDP Sciences

Indexing

ISI Web of Knowledge - 3 Citations

Scopus - 4 Citations

Other information

Authenticus ID: P-00Y-GN1

DOI: 10.1051/0004-6361/202143007

Abstract (EN): We present radial velocity follow-up obtained with ESPRESSO of the M-type star LTT 1445A (TOI-455), for which a transiting planet b with an orbital period of 5.4 days was detected by TESS. We report the discovery of a second transiting planet (LTT 1445A c) and a third non-transiting candidate planet (LTT 1445A d) with orbital periods of 3.12 and 24.30 days, respectively. The host star is the main component of a triple M-dwarf system at a distance of 6.9 pc. We used 84 ESPRESSO high-resolution spectra to determine accurate masses of 2.3 +/- 0.3 M-circle plus and 1.0 +/- 0.2 M-circle plus for planets b and c and a minimum mass of 2.7 +/- 0.7 M-circle plus for planet d. Based on its radius of 1.43 +/- 0.09 R-circle plus as derived from the TESS observations, LTT 1445A b has a lower density than the Earth and may therefore hold a sizeable atmosphere, which makes it a prime target for the James Webb Space Telescope (JWST). We used a Bayesian inference approach with the nested sampling algorithm and a set of models to test the robustness of the retrieved physical values of the system. There is a probability of 85% that the transit of planet c is grazing, which results in a retrieved radius with large uncertainties at 1.60(-0.34)(+0.67) R-circle plus. LTT 1445A d orbits the inner boundary of the habitable zone of its host star and could be a prime target for the JWST.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 29