A Spectroscopic Survey of the Youngest Field Stars in the Solar Neighborhood. II. The optically faint sample

Abstract

Star formation in the solar neighborhood is mainly traced by young stars in open clusters, associations and in the field, which can be identified by their X-ray emission. The determination of stellar parameters for the counterparts of X-ray sources is crucial for their study. This work extends the spectroscopic study of the RasTyc sample, based on TYCHO and RASS catalogs, to stars fainter than V=9.5 mag. We acquired 625 high-resolution spectra for 443 targets with four different instruments in the Northern hemisphere. The radial and rotational velocity (vsini) of our targets are measured by means of the cross-correlation technique, which is also helpful to discover binaries and multiple systems. We use the code ROTFIT for determining the atmospheric parameters and vsini of the single stars and SB1 systems. For these objects, we also measured the equivalent widths of the H$\alpha$ and LiI-6708Å lines, which enables us to derive their chromospheric activity level and lithium abundance. We make use of Gaia DR1 parallaxes and proper motions for locating the targets in the HR diagram and for computing the space velocity components of the youngest objects. We find a remarkable fraction (>35%) of binaries and multiple systems. Our sample is mostly (60%) composed of stars younger than the members of the UMa cluster. We identify 42 very young stars, which lie above or very close to the Pleiades upper envelope of the lithium abundance. A significant fraction (12%) of giants/subgiants stars is also present in our sample. Some of them are also lithium rich (A(Li)>1.4).

47 pages, 10 figures, accepted by A&A

References in corpus (19)

• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• The Radial Velocity Experiment (RAVE): Fifth Data Release
• Second ROSAT all-sky survey (2RXS) source catalogue
• X-Shooter spectroscopy of young stellar objects in Lupus: Accretion properties of class II and transitional objects
• Search for Associations Containing Young stars (SACY): I. Sample & Searching Method
• The Palomar/Keck Adaptive Optics Survey of Young Solar Analogs: Evidence for a Universal Companion Mass Function
• High-Dispersion Optical Spectra of Nearby Stars Younger Than The Sun
• TASS Mark IV Photometric Survey of the Northern Sky
• New periodic variable stars coincident with ROSAT sources discovered using SuperWASP
• The International Deep Planet Survey II: The frequency of directly imaged giant exoplanets with stellar mass
• The Gaia-ESO Survey: Chromospheric Emission, Accretion Properties, and Rotation in $\gamma$ Velorum and Chamaeleon I
• The VLT/NaCo Large program to probe the occurrence of exoplanets and brown dwarfs in wide orbits: I- Sample definition and characterization
• LACEwING: A New Moving Group Analysis Code
• Search for associations containing young stars (SACY). V. Is multiplicity universal? Tight multiple systems
• The SEEDS High Contrast Imaging Survey of Exoplanets around Young Stellar Objects
• Radial Velocity Studies of Close Binary Stars.XIII
• The differential rotation of epsilon Eri from MOST data
• New triple systems in the RasTyc sample of stellar X-ray sources
• Spectral Classification of Optical Counterparts to ROSAT All-Sky Survey X-ray Sources

Cited by in corpus (26)

• A Volume Limited Sample of Cataclysmic Variables from $Gaia$ DR2: Space Density and Population Properties
• HD 181068: A Red Giant in a Triply-Eclipsing Compact Hierarchical Triple System
• Stars with Photometrically Young Gaia Luminosities Around the Solar System (SPYGLASS) I: Mapping Young Stellar Structures and their Star Formation Histories
• The Gaia-ESO Survey: Empirical estimates of stellar ages from lithium equivalent widths (EAGLES)
• Rotation Periods, Inclinations, and Obliquities of Cool Stars Hosting Directly Imaged Substellar Companions: Spin-Orbit Misalignments are Common
• The SPHERE infrared survey for exoplanets (SHINE)- I Sample definition and target characterization
• Calibration of the Halpha Age-Activity relation for M dwarfs
• ACRONYM III: Radial Velocities for 336 Candidate Young Low-Mass Stars in the Solar Neighborhood, Including 78 Newly Confirmed Young Moving Group Members
• KMOS study of the mass accretion rate from Class I to Class II in NGC 1333
• The Gaia-ESO Survey: properties of newly discovered Li-rich giants
• What happened before? -- The disks around the precursors of young Herbig Ae/Be stars
• SPYGLASS. II. The Multi-Generational and Multi-Origin Star Formation History of Cepheus Far North
• The Epoch of Giant Planet Migration Planet Search Program. I. Near-Infrared Radial Velocity Jitter of Young Sun-like Stars
• Stellar Population Astrophysics (SPA) with the TNG: Stock 2, a little-studied open cluster with an eMSTO
• An asteroseismic age estimate of the open cluster NGC 6866 using Kepler and Gaia
• Characterization of Kepler targets based on medium-resolution LAMOST spectra analyzed with ROTFIT
• Search for planets around stars with wide brown dwarfs
• Discovery of new members of the nearby young stellar association in Cepheus
• The stellar system HIP 101227: is it a binary, a triple or a quadruple system?
• LAMOST medium-resolution observations of the Pleiades
• A Multiwavelength Machine-learning Approach to Classifying X-ray Sources in the Fields of Unidentified 4FGL-DR4 sources
• The bi-modal ${}^7$Li distribution of the Milky Way's thin-disk dwarf stars: The role of Galactic-scale events and stellar evolution
• High-resolution spectroscopic study of dwarf stars in the northern sky: Na to Zn abundances in two fields with radii of 20 degrees
• New, late-type spectroscopic binaries with X-ray emission
• iSTARMOD: A Python Code to Quantify Chromospheric Activity by Using the Spectral Subtraction Technique
• Radio emission from flaring stars and brown dwarfs