TY - JOUR
T1 - Discovery of new companions to high proper motion stars from the VVV survey
AU - Ivanov, Valentin D.
AU - Minniti, Dante
AU - Hempel, Maren
AU - Kurtev, Radostin
AU - Toledo, Ignacio
AU - Saito, Roberto K.
AU - Alonso-García, Javier
AU - Beamín, Juan Carlos
AU - Borissova, Jura
AU - Catelan, Márcio
AU - Chené, André Nicolas
AU - Emerson, Jim
AU - González, Óscar A.
AU - Lucas, Phillip W.
AU - Martín, Eduardo L.
AU - Rejkuba, Marina
AU - Gromadzki, Mariusz
N1 - Funding Information:
We acknowledge support by the FONDAP Center for Astrophysics 15010003; BASAL CATA Center for Astrophysics and Associated Technologies PFB-06; the Ministry for the Economy, Development, and Tourism’s Programa Iniciativa Científica Milenio through grant P07-021-F, awarded to The Milky Way Millennium Nucleus; FONDECYT grants No. 1090213 and 1110326 from CONICYT, and the European Southern Observatory. J.C.B. acknowledge support from a Ph.D. Fellowship from CONICYT. M.G. is financed by the GEMINI-CONICYT Fund, allocated to the project 32110014. R.K. acknowledges partial support from FONDECYT through grant 1130140. E.L.M. acknowledges support from grant AyA2011-30147-C03-03; J.B. acknowledge support from FONDECYT No. 1120601; A.N.C. acknowledges support from GEMINI-CONICYT No. 32110005 and from Comitee Mixto ESO-GOBIERNO DE CHILE. J.A.G. acknowledges support from Proyecto Fondecyt Postdoctoral 3130552, Fondecyt Regular 1110326, and Anillos ACT-86. We gratefully acknowledge use of data from the ESO VISTA telescope, and data products from the Cambridge Astronomical Survey Unit. We have also made extensive use of the SIMBAD Database at CDS Strasbourg, of the 2MASS, which is a joint project of the University of Massachusetts and IPAC/CALTECH, funded by NASA and NSF, and of the VizieR catalogue access tool, CDS, Strasbourg, France. Last but not least, we thank the anonymous referee for the thoughtful and helpful comments that greatly improved the scientific content of paper.
PY - 2013/12
Y1 - 2013/12
N2 - Context. The severe crowding in the direction of the inner Milky Way suggests that the census of stars within a few tens of parsecs in that direction may not be complete. Aims. We searched for new nearby object companions of known high proper motion (HPM) stars located towards the densest regions of the southern Milky Way where the background contamination presented a major problem to previous observations. Methods. The common proper motion (PM) method was used. We inspected the area around 167 known HPM (≥200 mas yr-1) stars: 67 in the disk and 100 in the bulge. Multi-epoch images were provided by the Two Micron All Sky Survey (2MASS) and the VISTA Variables in Via Lactea (VVV). The VVV is a new on-going ZYJHKS plus multi-epoch K S survey of ~562 deg2 of the Milky Way bulge and inner southern disk. Results. Seven new co-moving companions were discovered around known HPM stars (L 149-77, LHS 2881, L 200-41, LHS 3188, LP 487-4, LHS 5333, and LP 922-16); six known co-moving pairs were recovered (LTT 5140 A + LTT 5140 B, L 412-3 + L 412-4, LP 920-25 + LP 920-26, LTT 6990 A + LTT 6990 B, M 124.22158.2900 + M 124.22158.2910, and GJ 2136 A + GJ 2136 B); a pair of stars that was thought to be co-moving was found to have different proper motions (LTT 7318, LTT 7319); published HPMs of eight stars were not confirmed (C* 1925, C* 1930, C* 1936, CD-60 4613, LP 866-17, OGLE BUL-SC20 625107, OGLE BUL-SC21 298351, and OGLE BUL-SC32 388121); last but not least, spectral types ranging from G8V to M5V were derived from new infrared spectroscopy for seventeen stars, members of the co-moving pairs. Conclusions. The seven newly discovered stars constitute ~4% of the nearby HPM star list, but this is not a firm limit on the HPM star incompleteness because our starting point - the HPM list assembled from the literature - is incomplete itself, missing many nearby HPM M- and L-type objects, and it is contaminated with non-HPM stars. We have demonstrated that the superior sub-arcsec spatial resolution, with respect to previous surveys, allows the VVV to examine in greater detail the binary nature nature of known HPM stars. The ≥5 yr span of VVV will provide a sufficient baseline for finding new HPM stars from VVV data alone.
AB - Context. The severe crowding in the direction of the inner Milky Way suggests that the census of stars within a few tens of parsecs in that direction may not be complete. Aims. We searched for new nearby object companions of known high proper motion (HPM) stars located towards the densest regions of the southern Milky Way where the background contamination presented a major problem to previous observations. Methods. The common proper motion (PM) method was used. We inspected the area around 167 known HPM (≥200 mas yr-1) stars: 67 in the disk and 100 in the bulge. Multi-epoch images were provided by the Two Micron All Sky Survey (2MASS) and the VISTA Variables in Via Lactea (VVV). The VVV is a new on-going ZYJHKS plus multi-epoch K S survey of ~562 deg2 of the Milky Way bulge and inner southern disk. Results. Seven new co-moving companions were discovered around known HPM stars (L 149-77, LHS 2881, L 200-41, LHS 3188, LP 487-4, LHS 5333, and LP 922-16); six known co-moving pairs were recovered (LTT 5140 A + LTT 5140 B, L 412-3 + L 412-4, LP 920-25 + LP 920-26, LTT 6990 A + LTT 6990 B, M 124.22158.2900 + M 124.22158.2910, and GJ 2136 A + GJ 2136 B); a pair of stars that was thought to be co-moving was found to have different proper motions (LTT 7318, LTT 7319); published HPMs of eight stars were not confirmed (C* 1925, C* 1930, C* 1936, CD-60 4613, LP 866-17, OGLE BUL-SC20 625107, OGLE BUL-SC21 298351, and OGLE BUL-SC32 388121); last but not least, spectral types ranging from G8V to M5V were derived from new infrared spectroscopy for seventeen stars, members of the co-moving pairs. Conclusions. The seven newly discovered stars constitute ~4% of the nearby HPM star list, but this is not a firm limit on the HPM star incompleteness because our starting point - the HPM list assembled from the literature - is incomplete itself, missing many nearby HPM M- and L-type objects, and it is contaminated with non-HPM stars. We have demonstrated that the superior sub-arcsec spatial resolution, with respect to previous surveys, allows the VVV to examine in greater detail the binary nature nature of known HPM stars. The ≥5 yr span of VVV will provide a sufficient baseline for finding new HPM stars from VVV data alone.
KW - Astrometry
KW - Binaries: general
KW - Proper motions
KW - Solar neighborhood
KW - Stars: general
UR - http://www.scopus.com/inward/record.url?scp=84889022901&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/201321045
DO - 10.1051/0004-6361/201321045
M3 - Article
AN - SCOPUS:84889022901
SN - 0004-6361
VL - 560
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A21
ER -