J/A+A/673/A69 LTT 1445A ESPRESSO observations (Lavie+, 2023)
Planetary system around LTT 1445A unveiled by ESPRESSO:
Multiple planets in a triple M-dwarf system.
Lavie B., Bouchy F., Lovis C., Zapatero Osorio M., Deline A., Barros S.,
Figueira P., Sozzetti A., Gonzalez Hernandez J.I., Lillo-Box J.,
Rodrigues J., Mehner A., Damasso M., Adibekyan V., Alibert Y.,
Allende Prieto C., Cristiani S., D'Odorico V., Di Marcantonio P.,
Ehrenreich D., Genova Santos R., Lo Curto G., Martins C.J.A.P., Micela G.,
Molaro P., Nunes N., Palle E., Pepe F., Poretti E., Rebolo R., Santos N.,
Sousa S., Suarez Mascareno A., Tabrenero H., Udry S.
<Astron. Astrophys. 673, A69 (2023)>
=2023A&A...673A..69L 2023A&A...673A..69L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Stars, M-type ; Exoplanets ;
Radial velocities
Keywords: planets and satellites: detection -
planets and satellites: terrestrial planets -
techniques: radial velocities -techniques: photometry -
stars: individual: TOI-455 - stars: individual: LTT 1445
Abstract:
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 6.9pc. We used 84 ESPRESSO
high-resolution spectra to determine accurate masses of
2.3±0.3M⊕ and 1.0±0.2M⊕ for planets b and c and a
minimum mass of 2.7±0.7M⊕ for planet d. Based on its radius
of 1.43±0.09 R⊕ 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. 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+0.67-0.34R⊕. LTT
1445A d orbits the inner boundary of the habitable zone of its host
star and could be a prime target for the James Webb Space Telescope.
Description:
We carried out the radial velocity monitoring of the system with the
ESPRESSO spectrograph installed at the VLT in the Paranal Observatory
in Chile.
Objects:
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RA (2000) DE Designation(s)
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03 01 51.39 -16 35 36.0 LTT 1445A = BD-17 588A
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
espresso.dat 214 85 LTT 1445A ESPRESSO observations
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See also:
J/AJ/163/168 : Photometry and radial velocity of LTT 1445A (Winters+, 2022)
Byte-by-byte Description of file: espresso.dat
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Bytes Format Units Label Explanations
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1- 11 F11.6 d BJD Observation date (BJD-2450000)
13- 24 F12.6 m/s RV Radial velocity
26- 36 F11.9 m/s e_RV Radial velocity error
38- 48 F11.6 m/s FWHM Full width at half maximum
50- 60 F11.9 m/s e_FWHM Full width at half maximum error
62- 73 F12.9 --- Contrast Contrast
75- 85 F11.9 --- e_Contrast Contrast error
87- 97 F11.9 --- Halpha Hα activity index
99-109 E11.9 --- e_Halpha Hα activity index error
111-122 F12.9 --- S S activity index
124-134 F11.9 --- e_S S activity index error
136-146 F11.9 --- NaD NaD activity index
148-158 E11.9 --- e_NaD NaD activity index error
160-171 F12.9 --- Ca Ca activity index
173-183 F11.9 --- e_Ca Ca activity index error
185-200 F16.9 --- RHK ?=-99999 RHK activity index
202-214 F13.9 --- e_RHK ?=-99 RHK activity index error
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Acknowledgements:
Baptiste Lavie, baptiste.lavie(at)unige.ch
(End) Patricia Vannier [CDS] 10-Apr-2023