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Table · dataset · 2024

Barnard's star radial velocity curves

Listed in IVOA Registry (Virtual Observatory)

ESPRESSO guaranteed time observations (GTO) at the 8.2m-VLT telescope aimed at finding Earth-like exoplanets in the habitable zone of nearby stars.

Description

Barnard's star is a primary target within the ESPRESSO GTO as it is the second closest neighbour to our Sun after the alpha Centauri stellar system. We present here a large set of 156 ESPRESSO observations of Barnard's star taken over four years with the goal of exploring periods shorter than 50 days, thus including the habitable zone.

The analysis of ESPRESSO data using Gaussian process (GP) to model stellar activity suggests a long-term activity cycle at 3200d and confirms stellar activity due to rotation at 140d as the dominant source of RV variations. These results are supported by adding publicly available HARPS, HARPS-N and CARMENES data. ESPRESSO RVs do not support the existence of the previously reported candidate planet at 233 d.

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Results. ESPRESSO RVs reveal, after subtracting the GP model, several short period candidate planet signals at periods 3.15d, 4.12d, 2.34d and 6.74d. We confirm the 3.15d signal as a sub-Earth mass planet, with a semi-amplitude of 55+/-7cm/s, leading to a planet minimum mass m_p_sini of 0.37+/-0.05M_{Earth}_, about three times the mass of Mars.

ESPRESSO RVs provide hints of a candidate system with four sub-Earth mass planets in circular orbits with semi-amplitudes from 20 to 47cm/s, thus corresponding to minimum masses in the range 0.17-0.32M_{Earth}_. The sub-Earth mass planet at 3.1533+/-0.0006d is in a closely circular orbit with a semi-major axis of 0.0229+/-0.0003AU, thus located inner to the habitable zone of Barnard's star, with an equilibrium temperature of 400K.

The other three candidate signals will require additional ESPRESSO observations to be confirmed as a compact short-period planet system orbiting Barnard's star inner to its habitable zone.

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Catalogue records · 2

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Provenance · 1 source records, 8 field assertions
SourceKeyLast seenRaw
IVOA Registry (Virtual Observatory)ivo://cds.vizier/j/a+a/690/a7910 d agoJSON v1
FieldAssertionExtractorEvidence
access_levelsource · IVOA Registryconnector:ivoa_registry@1.0.0
concepts[field].local:field:astronomymapping · IVOA Registryconnector:ivoa_registry@1.0.0
concepts[modality].ivoa_waveband:opticalsource · IVOA Registryconnector:ivoa_registry@1.0.0
descriptionsource · IVOA Registryconnector:ivoa_registry@1.0.0rr.resource.res_description
license_textsource · IVOA Registryconnector:ivoa_registry@1.0.0
publication_datesource · IVOA Registryconnector:ivoa_registry@1.0.0
titlesource · IVOA Registryconnector:ivoa_registry@1.0.0rr.resource.res_title
updated_datesource · IVOA Registryconnector:ivoa_registry@1.0.0