1 / 27

Proper-motion companions to nearby stars in the local association

Proper-motion companions to nearby stars in the local association. Francisco Javier Alonso Floriano (UCM) José Antonio Caballero (CAB) David Montes (UCM). Common Proper Motion Companions. HD 82939 “A”. Same µ Same d?. GJ 9303 “B”. POSS2UKSTU-IR POSS2UKSTU-Red POSS2UKSTU-Blue.

oral
Download Presentation

Proper-motion companions to nearby stars in the local association

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  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 • ε Cha • 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 • Maximum difference 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 • Astrometric measurements for 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

More Related