RVSPY -- Radial Velocity Survey for Planets around Young Stars. Target characterization and high-cadence survey

Abstract

We introduce our Radial Velocity Survey for Planets around Young stars (RVSPY), characterise our target stars, and search for substellar companions at orbital separations smaller than a few au from the host star. We use the FEROS spectrograph to obtain high signal-to-noise spectra and time series of precise radial velocities (RVs) of 111 stars most of which are surrounded by debris discs. Our target stars have spectral types between early F and late K, a median age of 400 Myr, and a median distance of 45 pc. We determine for all target stars their basic stellar parameters and present the results of the high-cadence RV survey and activity characterization. We achieve a median single-measurement RV precision of 6 m/s and derive the short-term intrinsic RV scatter of our targets (median 22 m/s), which is mostly caused by stellar activity and decays with age from >100 m/s at <20 Myr to <20 m/s at >500 Myr. We discover six previously unknown close companions with orbital periods between 10 and 100 days, three of which are low-mass stars, and three are in the brown dwarf mass regime. We detect no hot companion with an orbital period <10 days down to a median mass limit of ~1 M_Jup for stars younger than 500 Myr, which is still compatible with the established occurrence rate of such companions around main-sequence stars. We find significant RV periodicities between 1.3 and 4.5 days for 14 stars, which are, however, all caused by rotational modulation due to starspots. We also analyse the TESS photometric time series data and find significant periodicities for most of the stars. For 11 stars, the photometric periods are also clearly detected in the RV data. We also derive stellar rotation periods ranging from 1 to 10 days for 91 stars, mostly from TESS data. From the intrinsic activity-related short-term RV jitter, we derive the expected mass-detection thresholds for longer-period companions.

24 pages, 14 figures, 4 tables; Accepted for publication in A&A

References in corpus (20)

• The Gaia mission
• The Transiting Exoplanet Survey Satellite
• The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
• New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey
• CERES: A Set of Automated Routines for Echelle Spectra
• Stellar activity of planetary host star HD 189733
• Search for exoplanets with the radial-velocity technique: quantitative diagnostics of stellar activity
• Abundance to age ratios in the HARPS-GTO sample with Gaia DR2: Chemical clocks for a range of [Fe/H]
• Extrasolar planets and brown dwarfs around A-F type stars VI. High precision RV survey of early type dwarfs with HARPS
• Do Two Temperature Debris Disks Have Multiple Belts?
• Stirring in massive, young debris discs from spatially resolved Herschel images
• A Direct Imaging Survey of Spitzer detected debris disks: Occurrence of giant planets in dusty systems
• Planet populations inferred from debris discs: insights from 178 debris systems in the ISPY, LEECH and LIStEN planet-hunting surveys
• Extrasolar planets and brown dwarfs around AF-type stars. IX. The HARPS southern sample
• The beta Pictoris association: Catalog of photometric rotational periods of low-mass members and candidate members
• The vertical structure of debris disks and the impact of gas
• A HARPS RV search for planets around young nearby stars
• The First Scattered Light Image of the Debris Disk around the Sco-Cen target HD 129590
• No significant correlation between radial velocity planet presence and debris disc properties
• Radial-velocity jitter of stars as a function of observational timescale and stellar age

Cited by in corpus (1)

• Radial Velocity Survey for Planets around Young stars (RVSPY) A transiting warm super-Jovian planet around HD 114082, a young star with a debris disk