1. Astrometric detection of a Neptune-mass candidate planet in the nearest M-dwarf binary system GJ65 with VLTI/GRAVITY.
- Author
-
GRAVITY Collaboration, Abuter, R., Amorim, A., Benisty, M., Berger, J. P., Bonnet, H., Bourdarot, G., Bourget, P., Brandner, W., Clénet, Y., Davies, R., Delplancke-Ströbele, F., Dembet, R., Drescher, A., Eckart, A., Eisenhauer, F., Feuchtgruber, H., Finger, G., Förster Schreiber, N. M., and Garcia, P.
- Subjects
PLANETARY orbits ,GRAVIMETRY ,ORBITS (Astronomy) ,ASTROMETRY ,GROUND motion ,GRAVITY ,PLANETARY science - Abstract
The detection of low-mass planets orbiting the nearest stars is a central stake of exoplanetary science, as they can be directly characterized much more easily than their distant counterparts. Here, we present the results of our long-term astrometric observations of the nearest binary M-dwarf Gliese 65 AB (GJ65), located at a distance of only 2.67 pc. We monitored the relative astrometry of the two components from 2016 to 2023 with the VLTI/GRAVITY interferometric instrument. We derived highly accurate orbital parameters for the stellar system, along with the dynamical masses of the two red dwarfs. The GRAVITY measurements exhibit a mean accuracy per epoch of 50−60 ms in 1.5 h of observing time using the 1.8 m Auxiliary Telescopes. The residuals of the two-body orbital fit enable us to search for the presence of companions orbiting one of the two stars (S-type orbit) through the reflex motion they imprint on the differential A–B astrometry. We detected a Neptune-mass candidate companion with an orbital period of p = 156 ± 1 d and a mass of m
p = 36 ± 7 M⊕ . The best-fit orbit is within the dynamical stability region of the stellar pair. It has a low eccentricity, e = 0.1 − 0.3, and the planetary orbit plane has a moderate-to-high inclination of i > 30° with respect to the stellar pair, with further observations required to confirm these values. These observations demonstrate the capability of interferometric astrometry to reach microarcsecond accuracy in the narrow-angle regime for planet detection by reflex motion from the ground. This capability offers new perspectives and potential synergies with Gaia in the pursuit of low-mass exoplanets in the solar neighborhood. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF