000006077 001__ 6077
000006077 005__ 20230113145314.0
000006077 0247_ $$2DOI$$a10.1093/mnras/stac2674
000006077 037__ $$aSCART-2023-0037
000006077 100__ $$aBoulkaboul, A.
000006077 245__ $$aAnalysis of Gaia radial-velocity standards: stability and new substellar companion candidates 
000006077 260__ $$c2022
000006077 520__ $$aOur main aim is to test the non-variability of the radial velocity (RV) of a sample of 2351 standard stars used for wavelength calibration of the Radial Velocity Spectrometer (RVS) instrument onboard Gaia. In this paper, we present the spectroscopic analysis of these stars with the determination of their physical parameters by matching observed and synthetic spectra. We estimate the offset between different instruments after determining the shift between measured and archived RVs since the instrument pipelines use various numerical masks. Through the confirmation of the stability of the target RVs, we find 68 stars with a long-term variation having an acceleration that exceeds 10m/s/yr⁠. This suggests a barycentric reflex motion caused by a companion. As activity phenomena may be the source of periodic and trend-like RV variations in stars with putative planetary companions, we analysed various activity indicators in order to check their correlations to the RV changes. Among the trend stars, 18 have a trend model scatter greater than 100 m/s over a time span from 10 to 12 yr. We also confirm that six stars with known substellar companions have a total model scatter, 3σ, exceeding the threshold set by Gaia, that is, 300 m/s⁠. In addition, TYC8963-01543-1, an SB2 star, has data scatter σ=176.6 m/s⁠. Four more other stars are revealed to be variable after combining data from different instruments. Despite the presence of low-amplitude changes, a very large fraction of our sample (98.8 per cent) appears suitable as RV calibrators for Gaia RVS.
000006077 536__ $$aGaia PRODEX/$$cGaia PRODEX/$$fGaia PRODEX
000006077 594__ $$aNO
000006077 6531_ $$atechniques: radial velocities
000006077 6531_ $$astars: activity
000006077 6531_ $$astars: binaries: spectroscopic
000006077 6531_ $$astars: fundamental parameters
000006077 700__ $$aDamerdji, Y.
000006077 700__ $$aMorel, T.
000006077 700__ $$aFrémat, Y.
000006077 700__ $$aSoubiran, C.
000006077 700__ $$aGosset, E.
000006077 700__ $$aAbdelatif, T. E.
000006077 773__ $$c1849–1866$$n2$$pMonthly Notices of the Royal Astronomical Society$$v517$$y2022
000006077 8560_ $$fronny.blomme@observatoire.be
000006077 85642 $$ahttps://academic.oup.com/mnras/article/517/2/1849/6711702
000006077 85642 $$ahttps://ui.adsabs.harvard.edu/abs/2022MNRAS.517.1849B/abstract
000006077 905__ $$apublished in
000006077 980__ $$aREFERD