Bibcode
Jiménez-Esteban, F. M.; Caballero, J. A.; Dorda, R.; Miles-Páez, P. A.; Solano, E.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 539, id.A86
Fecha de publicación:
3
2012
Revista
Número de citas
10
Número de citas referidas
9
Descripción
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 μ > 50 mas yr-1 and very
red VT - 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 2.2 m 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 VT ≈ 10.8-11.3 mag, reduced proper
motions midway between known dwarfs and giants, near-infrared colours
typical of giants, and effective temperatures Teff ≈
2900-3400 K. 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.