J/A+A/642/A121 LHS1140 radial velocity data (Lillo-Box+, 2020)
The LHS1140 planetary system revisited by ESPRESSO and TESS.
Lillo-Box J., Figueira P., Leleu A., Acuna L., Faria J.P., Hara N.,
Santos N.C., Correia A.C.M., Robutel P., Deleuil M., Barrado D., Sousa S.,
Bonfils X., Mousis O., Almenara J.M., Astudillo-Defru N., Marcq E., Udry S.,
Lovis C., Pepe F.
<Astron. Astrophys. 642, A121 (2020)>
=2020A&A...642A.121L 2020A&A...642A.121L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Radial velocities
Keywords: planets and satellites: terrestrial planets -
planets and satellites: composition -
planets and satellites: interiors -
planets and satellites: individual: LHS1140 -
techniques: radial velocities - techniques: photometric
Abstract:
LHS 1140 is an M dwarf known to host two transiting planets at orbital
periods of 3.77 and 24.7 days. They were detected with HARPS and
Spitzer. The external planet (LHS 1140 b) is a rocky super-Earth that
is located in the middle of the habitable zone of this low-mass star.
All these properties place this system at the forefront of the
habitable exoplanet exploration, and it therefore constitutes a
relevant case for further astrobiological studies, including
atmospheric observations.
We further characterize this system by improving the physical and
orbital properties of the known planets, search for additional
planetary-mass components in the system, and explore the possibility
of co-orbitals.
We collected 113 new high-precision radial velocity observations with
ESPRESSO over a 1.5-yr time span with an average photon-noise
precision of 1.07m/s. We performed an extensive analysis of the
HARPS and ESPRESSO datasets and also analyzed them together with the
new TESS photometry. We analyzed the Bayesian evidence of several
models with different numbers of planets and orbital configurations.
We significantly improve our knowledge of the properties of the known
planets LHS 1140 b (Pb∼24.7-days) and LHS 1140 c (Pc∼3.77-days). We
determine new masses with a precision of 6% for LHS 1140 b
(6.48±0.46MEarth) and 9% for LHS 1140 c
(mc=1.78±0.17MEarth). This reduces the uncertainties relative to
previously published values by half. Although both planets have
Earth-like bulk compositions, the internal structure analysis suggests
that LHS 1140 b might be iron-enriched and LHS 1140 c might be a true
Earth twin. In both cases, the water content is compatible to a
maximum fraction of 10-12% in mass, which is equivalent to a deep
ocean layer of 779±650 km for the habitable-zone planet LHS 1140 b.
Our results also provide evidence for a new planet candidate in the
system (md=4.8±1.1MEarth) on a 78.9-day orbital period, which is
detected through three independent methods. The analysis also allows
us to discard other planets above 0.5MEarth for periods shorter
than 10 days and above 2 MEarth for periods up to one year. Finally,
our co-orbital analysis discards co-orbital planets in the tadpole and
horseshoe configurations of LHS 1140 b down to 1MEarth with a 95%
confidence level (twice better than with the previous HARPS dataset).
Indications for a possible co-orbital signal in LHS 1140 c are
detected in both radial velocity (alternatively explained by a high
eccentricity) and photometric data (alternatively explained by
systematics), however.
The new precise measurements of the planet properties of the two
transiting planets in LHS 1140 as well as the detection of the planet
candidate LHS 1140 d make this system a key target for atmospheric
studies of rocky worlds at different stellar irradiations.
Description:
In depth characterization of the planet masses and radii in the
LHS1140 planetary system through observations with ESPRESSO and TESS.
Objects:
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RA (2000) DE Designation(s)
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00 44 59.33 -15 16 17.5 LHS1140 = PM J00449-1516
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tableb1.dat 59 112 Radial velocity data set for LHS1140
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Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 14 F14.6 d BJD Barycentric Julian date
16- 24 F9.5 km/s RV Radial velocity corrected for instrument offset
26- 32 F7.5 km/s e_RV Radial velocity uncertainty
34- 39 F6.4 km/s FWHM FWHM of the CCF
41- 46 F6.4 km/s e_FWHM FWHM uncertainty of the CCF
48- 59 A12 --- Inst Instrument (ESPRESSOpre or ESPRESSOpost)
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Acknowledgements:
Jorge Lillo-Box, Jorge.Lillo(at)cab.inta-csic.es
(End) Lillo-Box Jorge [CAB], Patricia Vannier [CDS] 26-Sep-2020