X-Shooter Survey of Young Intermediate Mass Stars -- I. Stellar Characterization and Disc Evolution

Abstract

Intermediate mass stars (IMSs) represent the link between low-mass and high-mass stars and cover a key mass range for giant planet formation. In this paper, we present a spectroscopic survey of 241 young IMS candidates with IR-excess, the most complete unbiased sample to date within 300 pc. We combined VLT/X-Shooter spectra with BVR photometric observations and Gaia DR3 distances to estimate fundamental stellar parameters such as Teff, mass, radius, age, and luminosity. We further selected those stars within the intermediate mass range 1.5 <= Mstar/Msun <= 3.5 and discarded old contaminants. We used 2MASS and WISE photometry to study the IR-excesses of the sample, finding 92 previously unidentified stars with IR-excess. We classified this sample into 'protoplanetary', 'hybrid candidates' and 'debris' discs based on their observed fractional excess at 12microns, finding a new population of 17 hybrid disc candidates. We studied inner disc dispersal timescales for λ < 10μm and found very different trends for IMSs and low mass stars (LMSs). IMSs show excesses dropping fast during the first 6 Myrs independently of the wavelength, while LMSs show consistently lower fractions of excess at the shortest wavelengths and increasingly higher fractions for longer wavelengths, with slower dispersal rates. In conclusion, this study demonstrates empirically that IMSs dissipate their inner discs very differently than LMSs, providing a possible explanation for the lack of short period planets around IMSs.

19 pages, 11 figures, Accepted to MNRAS

References in corpus (35)

• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• Direct Imaging of Multiple Planets Orbiting the Star HR 8799
• Molecfit: A general tool for telluric absorption correction. I. Method and application to ESO instruments
• Molecfit: A general tool for telluric absorption correction II. Quantitative evaluation on ESO-VLT X-Shooter spectra
• A Steeper than Linear Disk Mass-Stellar Mass Scaling Relation
• Retired A Stars and Their Companions: Exoplanets Orbiting Three Intermediate-Mass Subgiants
• Precise Radial Velocities of Giant Stars VII. Occurrence Rate of Giant Extrasolar Planets as a Function of Mass and Metallicity
• Planets around evolved intermediate-mass stars. I. Two substellar companions in the open clusters NGC 2423 and NGC 4349
• Solar-type dynamo behaviour in fully convective stars without a tachocline
• On corotation torques, horseshoe drag and the possibility of sustained stalled or outward protoplanetary migration
• Planet Engulfment by ~1.5-3 Solar-Mass Red Giants
• Molecular gas in debris disks around young A-type stars
• Five steps in the evolution from protoplanetary to debris disk
• Assembling the Building Blocks of Giant Planets around Intermediate Mass Stars
• Homogeneous study of Herbig Ae/Be stars from spectral energy distributions and Gaia EDR3
• Bridging the gap between protoplanetary and debris disks: separate evolution of millimeter and micrometer-sized dust
• Catalogue of new Herbig Ae/Be and classical Be stars. A machine learning approach to Gaia DR2
• Search for associations containing young stars (SACY). V. Is multiplicity universal? Tight multiple systems
• A spectroscopic survey of Herbig Ae/Be stars with X-Shooter II: Accretion diagnostic lines
• Planet populations inferred from debris discs: insights from 178 debris systems in the ISPY, LEECH and LIStEN planet-hunting surveys
• New low-mass members of the Octans stellar association and an updated 30-40 Myr lithium age
• On the mass accretion rate and infrared excess in Herbig Ae/Be Stars
• Photoevaporative Dispersal of Protoplanetary Disks around Evolving Intermediate-mass Stars
• Population synthesis of exocometary gas around A stars
• The mass and size of Herbig disks as seen by ALMA
• Empirical classification of VLT/Giraffe stellar spectra in the wavelength range 6440-6810 A in the gamma Vel cluster, and calibration of spectral indices
• Formation of secondary atmospheres on terrestrial planets by late disk accretion
• Lack of other molecules in CO-rich debris discs: is it primordial or secondary gas?
• The Demographics of Wide-Separation Planets
• Spectroscopic monitoring of rapidly-rotating early-type stars in the Pleiades cluster
• Efficient Dust Radial Drift Around Young Intermediate-mass Stars
• The Scorpion Planet Survey: Wide-Orbit Giant Planets Around Young A-type Stars
• The GRAVITY Young Stellar Object survey VIII. Gas and dust faint inner rings in the hybrid disk of HD141569
• First detection of a disk free of volatile elements around a young A-type star: A sign of collisions between rocky planets?

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