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  1. Proper-motion companions to nearby stars in the local association Francisco Javier Alonso Floriano (UCM) José Antonio Caballero (CAB) David Montes (UCM)

  2. Common Proper Motion Companions HD 82939 “A” Same µ Same d? GJ 9303 “B” POSS2UKSTU-IR POSS2UKSTU-Red POSS2UKSTU-Blue

  3. StellarKinematicGroups Groups of stars with coherent Galactic velocities that may have a common origin

  4. Castor (200 Ma) IC 2391 (35-55 Ma) Other young stars + StellarKinematicGroups U-V, W-V diagrams (Montes et al. 2001) • Local Association (10-150 Ma) • Ursa Major (300 Ma) • Hyades (600 Ma)

  5. The Local Association and related subgroups • U-V, U-W diagrams and subgroups of the Local Association • (Torres et al. 2008) • β Pictoris • Tucana-Horologium • Columba • Carina X • TW Hydrae • εCha • AB Doradus

  6. Selection of thesample The sample belongs to the Local Association (Montes et al. 2001 and Torres et al. 2008) but we have divided the sample into three groups: • 44 objects belonging to the subgroup Tucana-Horologium • 50 objects belonging to the subgroup βPictoris. • 116 objects not belonging to the previous subgroup (referred to generically as this sample Local Association) 210

  7. Example (HD 82939) • Field and catalogue (Simbad, 2MASS, USNO-B1)

  8. Example (HD 82939) • “cross-match” and send planes The 2MASS catalogue is more reliable than USNO-B1. Sending planes with “Broadcast” (small antenna)

  9. Example (HD 82939) • We search for companions with the same proper motion • Maximumdifference of ±10 milliarcseconds per year pmDe pmRA

  10. Example (HD 82939) • Identify candidates: Primary + “secondary” + two unknown sources • J>15.5 magobjecttooweak • The object must correspond to a star well appointed • Checkforpropermotion (ifit’s in Simbad)

  11. CandidatesHowMany? 20 LA + 31 Tuc-Hor + 16 βPic = 67

  12. Rejection: PhotometricDistance I-K vs I PZ TEL “A” CD-50 12186 “B” Bluer than expected (for its distance and spectral type) • Colours • Expected magnitudes

  13. Rejection: PhotometricDistance Photometric distance calculated by fitting the color magnitude diagram (I-K vs MI). (Torres et al. 2008) Fitting for the Local Asociation

  14. Promising candidates From 67 candidates, after rejection, we have 23 common proper motion companions

  15. 14 known in Simbad + WDS

  16. New CMPs 8 in the data base Simbad, previouslyunrelatedtoeach

  17. New CMPs: Tuc-Hor Images made by POSS2UKSTU-IR POSS2UKSTU-Red POSS2UKSTU-Blue In Moving Group Not in Moving Group (unknown) ρ = 1411 arcsec HD 207964 (B) AF HOR (B) CD-53 544 (A) HD 207575 (A) ρ = 21.8 arcsec HD 13183 (A) CD-53 413 (B) ρ = 707 arcsec

  18. New CMPs: βPic HD 199143 (A) In Moving Group Not in Moving Group (unknown) Images made by POSS2UKSTU-IR POSS2UKSTU-Red POSS2UKSTU-Blue AZ Cap (B) η Tele (A) ρ = 328 arcsec TYC 9073-0762-1 (A) HD 181327 (B) HD 1713167 (B) ρ = 420 arcsec ρ = 553 arcsec

  19. New CMPs: LA ρ = 613 arcsec In Moving Group Not in Moving Group (unknown) HD 10008 (A) HD 82939 (A) G271-110 (B) Images made by POSS2UKSTU-IR POSS2UKSTU-Red POSS2UKSTU-Blue ρ = 163 arcsec GJ 9303 (B)

  20. New CMPs: LA NO Simbad ρ = 86.4 arcsec N E HD 143809 A HD 143809 B Image made by POSS2UKSTU-IR POSS2UKSTU-Red POSS2UKSTU-Blue

  21. Follow-up of HD 143809 • Astrometricmeasurementsfor HD 143809 B using 9 epochs. • 1954.05.25 POSSI Red1982.06.23 GSC 2.31990.06.18 POSSII Blue1991.06.17 POSSII IR1994.05.04 POSSII Red2000.05.01 2MASS2000.11.27 CMC142001.03.19 SDSS 2001.21422003.04.27 SDSS 2003.3221 • Proper motions and its standard deviation (σ) are obtained. • µαcosδ= -51.0 (1.3) mas/a • µδ = -40.7 (1.3) mas/a Example: BarnardStar POSS2UKSTU-IR POSS2UKSTU-Red POSS2UKSTU-Blue (at differentepochs)

  22. Follow-up of HD 143809 2.2 m Calar Alto, Almeria, Spain Image and Spectroscopy taken with the instrument CAFOS

  23. Image of HD 143809 A & B Measured values Values taken from the bibliography HD 143809 A HD 143809 B E R Filter N Magnitud of each component in different photometric bands

  24. Spectroscopy of HD 143809 A & B Hα en emisión Hα in emission TiO HD 143809 B (SpTcoolerthan A) CaH TiO Hβ in emission TiO CaH Ca II triplet TiO Telluric band Hγ in emission HD 143809 A (G0) Mg triplet Hα Na doublet Telluric band

  25. SpectralType of HD 143809 B Comparison with two spectral type standar stars GJ 767 B (M 0.5 V) HD 143809 B GJ 767 A (M 2 V)

  26. HD 143809 A & B E • HD 143809A y HD 143809B ρ= 1.44 arcmin (s = 6800 UA) Δμ = 2.9 (2.5) mas/a dA (77.6 ± 8.3 pc) ≈ dB EW(Li) = 103 mÅ (López-Santiago et al. 2010) τ ≈ 80-120 Ma (Montes et al. 2001) µαcosδ= -51.0(1.3) mas/a µδ = -40.7(1.3) mas/a H lines in emission SpT ≈ M1-1.5 V e dB = 74.1 pc Young and nearby CPM A & B N A B B POSS2UKSTU-IR POSS2UKSTU-Red POSS2UKSTU-Blue

  27. Conclusions • CPM search on 210 stars • 23 candidates confirmed • 14 candidates are known common proper motion companions • 9 stars are unknown multiple systems: • 4 new members in these moving groups • 1 candidate not previously described in the literature : HD 143809B (follow-up confirmation) • The results demonstrate the validity of the method