Identification of red high proper-motion objects in Tycho-2 and 2MASS catalogues using Virtual Observatory tools

Abstract

Aims: With available Virtual Observatory tools, we looked for new M dwarfs in the solar neighbourhood and M giants with high tangential velocities. Methods: From an all-sky cross-match between the optical Tycho-2 and the near-infrared 2MASS catalogues, we selected objects with proper motions >50mas/yr and very red V-Ks colours. For the most interesting targets, we collected multi-wavelength photometry, constructed spectral energy distributions, estimated effective temperatures and surface gravities from fits to atmospheric models, performed time-series analysis of ASAS V-band light curves, and assigned spectral types from low-resolution spectroscopy obtained with CAFOS at the 2.2m Calar Alto telescope. Results: We got a sample of 59 bright red high proper-motion objects, including fifty red giants, four red dwarfs, and five objects reported in this work for the first time. The five new stars have magnitudes V~10.8-11.3mag, reduced proper motions midway between known dwarfs and giants, near-infrared colours typical of giants, and effective temperatures Teff~2900-3400K. From our time-series analysis, we discovered a long secondary period in Ruber 4 and an extremely long primary period in Ruber 6. With the CAFOS spectra, we confirmed the red giant nature of Ruber 7 and 8, the last of which seems to be one of the brightest metal-poor M giants ever identified.

Accepted in Astronomy & Astrophysics

References in corpus (16)

• VOSA: Virtual Observatory SED Analyzer. An application to the Collinder 69 open cluster
• The First Hundred Brown Dwarfs Discovered by the Wide-field Infrared Survey Explorer (WISE)
• The Gemini Deep Planet Survey -- GDPS
• An All-Sky Catalog of Bright M Dwarfs
• PPM-Extended (PPMX) - a catalogue of positions and proper motions
• A White Light Megaflare on the dM4.5e Star YZ CMi
• CFBDS J005910.90-011401.3: reaching the T-Y Brown Dwarf transition?
• The Chemical Abundances of Stars in the Halo (CASH) Project. II. A Sample of 16 Extremely Metal-poor Stars
• Calibrated griz magnitudes of Tycho stars: All-sky photometric calibration using bright stars
• Young stars and brown dwarfs surrounding Alnilam (eps Ori) and Mintaka (del Ori)
• Semi-Regular Variables in the Solar Neighbourhood
• The mass ratio and the orbital parameters of the sdOB binary AA Doradus
• HI and CO in the circumstellar environment of the oxygen-rich AGB star RX Lep
• Post-processing the VLTI fringe-tracking data: First measurements of stars
• A search for new hot subdwarf stars by means of Virtual Observatory tools
• Identification of blue high proper motion objects in the Tycho-2 and 2MASS catalogues using Virtual Observatory tools

Cited by in corpus (8)

• CARMENES input catalogue of M dwarfs. I. Low-resolution spectroscopy with CAFOS
• The Gaia Ultracool Dwarf Sample. I. Known L and T dwarfs and the first Gaia data release
• Random Forest identification of the thin disk, thick disk and halo Gaia-DR2 white dwarf population
• Early optical follow-up of the nearby active star DG CVn during its 2014 superflare
• Search for bright nearby M dwarfs with Virtual Observatory tools
• Discovery of new members of the nearby young stellar association in Cepheus
• Stars and brown dwarfs in the sigma Orionis cluster. III. OSIRIS/GTC low-resolution spectroscopy of variable sources
• J-PLUS: Discovery and characterisation of ultracool dwarfs using Virtual Observatory tools