Una bsqueda de compaeros de estrellas Luyten con
Una búsqueda de compañeros de estrellas Luyten con el Observatorio Virtual A search for companions to Luyten stars with the Virtual Observatory José A. Caballero 1 F. Xavier Miret 2 Joan Genebriera 3 Tófol Tobal 2 Jordi Cairol 2 David Montes 1 1: Dpto. de Astrofísica, Universidad Complutense de Madrd 2: Observatori Astrònomic del Garraf, Barcelona 3: Observatorio de Tacande, La Palma
Albus 1 (Caballero & Solano 2007, Ap. J, 665, L 151) Serendipitous discovery of a very bright white dwarf candidate. . . that is actually one of the brightest He-B subdwarfs (Vennes, Kawka & Smith 2007, Ap. J, 668, L 59; A. Ulla et al. in prep. )
Koenigstuhl 1 AB (Caballero 2007 a, A&A, 462, L 61) The (second) widest ultracool binary: a challenge for very lowmass formation ejection scenarios! Seven astrometric epochs since 1977. 6 until 2004. 0: r = 77. 76(7) arcsec d = 23(2) pc r = 1800(170) AU MA = 0. 103(6) Msol MB = 0. 079(4) Msol
Koenigstuhl 2 AB (Caballero 2007 d, Ap. J, 667, 520) A new very low-mass star in a wide binary: the third widest system with MA + MB < 0. 4 Msol (in a draw) Primary: LP 655 -23 (Luyten 1979) Secondary: 2 M 0430 -08 (M 8. 0 V; Cruz et al. 2003) r = 450(40) AU MA = 0. 26(4) Msol MB = 0. 086(4) Msol
Koenigstuhl 3 ABC (Caballero 2007 d, Ap. J, 667, 520) Frequency of wide multiples with latetype (>M 5) components: 5. 0 ± 1. 8 % The widest system containing an L dwarf component Primary: HD 221356 (F 8. 0 V; Hipparcos) Secondary: 2 M 2331 -04 AB (M 8. 0 V+L 3. 0 V; Gizis et al. 2000, 2003) r = 7. 530(7) arcmin ! r = 11900(300) AU MA = 1. 02(7) Msol MBC = 0. 088+0. 072 Msol And Koenigstuhl 4 AB is coming! (Caballero, in prep. )
The Garraf survey: an Aladin-based search for common-, high-proper motion pairs • The New Luyten Two Tenths (NLTT) catalogue (Luyten 1979), m > 0. 2 arcsec a-1 • Improved astrometry in Salim & Gould (2003): 36 000 stars • Selection: proper motions between 0. 5 and 1. 0 arcsec a-1 • Still 1947 stars! • Using Aladin instead of Super. COSMOS Science Archive Still a lot of work one person. . .
Help #1: Xavier, Tófol and Xavier at the Observatori Astrònomic del Garraf OAG (1976): a non-proffesional centre dedicated to the study of visual double stars OAG revised the Comellas’ 1973. 0 and 1980. 0 catalogues and coordinated most of non-proffesional observations of doubles in Spain from 1990 to 2003 OAG is one the main measurement providers of the USNO Washington Double Stars catalogue (104)
The Garraf survey: Methodology • Data loading and cross-matching: USNO-B 1+2 MASS • Proper-motion diagram and candidate selection • Recovery of known pairs with incorrect USNO-B 1 proper motions with the “proper motion filter” • One-by-one inspection of all selected binary candidates (SIMBAD, CCDM, Tycho-2. . . )
The Garraf survey: Current status • ~160 common-m candidate companions studied to date • 86 rejected systems with bad USNOB 1 astrometry • 8 pairs with different USNO-B 1 proper motions • 20 physical systems with both star components in Hipparcos • 29 physical systems with only one star component in Hipparcos • 19 physical systems with no components in Hipparcos • Half a dozen new serendipitouslydiscovered physical systems
Help #2: The Tacande astro-photometric follow-up A battery of “small” telescopes in La Palma: 40, 20, 15, 12, 9 cm • 40 cm Cassegrain Relay, F 6/5, with a CCD ST 8 XE
Garraf 1 AB: An example of serendipitous discovery. . . A: G 125 -15, M 4. 5 e, X-ray, variable, age ~ 300 Ma (Daemgen et al. 2007) B: G 125 -14, M 5. 5? Known binary in Giclas et al. (1971)
Garraf 1 AB: A bright, young, very wide, low-mass binary in the solar neighbourhood Multi-epoch relative astrometry: 1952 Jul 17 POSSI Red 1988 Jun 13 POSSII Blue 1992 Aug 31 POSSII Red 1993 Jun 13 POSSII Infrared 1998 Jun 01 2 MASS 2001 Aug 26 CMC 14 2008 Mar 07 Tacande Age? r = 46. 0 ± 0. 3 arcsec = 347. 34 ± 0. 16 deg d = 17+6 -5 pc r = 800+300 -200 AU MA = 0. 21+0. 08 -0. 05 Msol MB = 0. 12+0. 04 -0. 03 Msol
Help #3: Optical imaging and low-resolution spectroscopy of Garraf 1 AB with CAFOS / 2. 2 m by David Montes M 4. 5 e + M 5. 0: e. Accurate BVRI magnitudes. New astrometric epoch (2008 Apr 30)
Conclusions A search for companions to Luyten stars with the Virtual Observatory What will be a trained investigator be able do with SDSS + UKIDSS + LSST + GAIA. . . ?
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