HD 196775

Last updated
HD 196775
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Delphinus [1]
Right ascension 20h 39m 04.9681s [2]
Declination +15° 50′ 17.511″ [2]
Apparent magnitude  (V)5.98 [3]
Characteristics
Evolutionary stage main sequence [2]
Spectral type B3 V [4]
U−B color index −0.71 [3]
B−V color index −0.16 [3]
Astrometry
Radial velocity (Rv)−4.6±1 [5] km/s
Proper motion (μ)RA: −0.868 mas/yr [2]
Dec.: −15.290 mas/yr [2]
Parallax (π)3.1211±0.0617  mas [2]
Distance 1,050 ± 20  ly
(320 ± 6  pc)
Absolute magnitude  (MV)−2.05 [1]
Details
Mass 7±0.4 [6]   M☉
Radius 4.13±0.14 [7]   R☉
Luminosity 1,507 [8]   L☉
Surface gravity (log g)3.97 [9]   cgs
Temperature 18,100 [9]   K
Rotational velocity (v sin i)145±6 [10]  km/s
Age 36.1±9.5 [6]   Myr
Other designations
AG+15°2265, BD+15°4220, GC 28785, HD 196775, HIP 101909, HR 7899, SAO 106347, WDS J20391+1550A
Database references
SIMBAD data

HD 196775 (HR 7899) is a solitary star in the equatorial constellation Delphinus. It has an apparent magnitude of 5.98, allowing it to be faintly seen with the naked eye. The object is relatively far at a distance of 1,050 light years but is approaching the Solar System with a heliocentric radial velocity of −4.6  km/s . HD 196775 has a high peculiar velocity of 21.8+1.9
−4.1  km/s [6] compared to neighboring stars, indicating that it may be a runaway star.

HD 196775 has a general stellar classification of B3 V, [4] indicating that it is an ordinary B-type main-sequence star. However, once source gives it a class of B4 Vn, [11] making it slightly cooler and having broad absorption lines due to rapid rotation. It has an angular diameter of 0.12  mas , [12] yielding a radius 4.13 times that of the Sun. [7] At present it has 7 times the mass of the Sun [6] and shines at 1507  L☉ [8] from its photosphere at an effective temperature of 18,100  K , [9] giving it a whitish blue hue. HD 196775 is 36 million years old [6] and is spinning rapidly with a projected rotational velocity of 145  km/s . [10]

HD 196775 has four faint optical companions whose parameters are listed below.

HD 196775's Companions [13]
Companionmv PA (°)YearSep. (″)
B12.4015420065.2
C11.31122201239.9
D14.40146201228.8
E14.4033201223.3

References

  1. 1 2 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters . 38 (5): 331. arXiv: 1108.4971 . Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. XHIP record for this object at VizieR.
  2. 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  3. 1 2 3 Oja, T. (September 1984). "UBV photometry of stars whose positions are accurately known". Astronomy and Astrophysics Supplement Series. 57: 357–359. Bibcode:1984A&AS...57..357O. ISSN   0365-0138.
  4. 1 2 Cucchiaro, A.; Jaschek, M.; Jaschek, C.; Macau-Hercot, D. (May 1980). "Spectral classification from the ultraviolet line features of S2/68 spectra". Astronomy and Astrophysics Supplement Series. 40: 207–213. Bibcode:1980A&AS...40..207C. ISSN   0365-0138.
  5. ↑ Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv: 1606.08053 . Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. ISSN   1063-7737. S2CID   119231169.
  6. 1 2 3 4 5 Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (October 12, 2010). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410 (1). Oxford University Press (OUP): 190–200. arXiv: 1007.4883 . Bibcode:2011MNRAS.410..190T. doi: 10.1111/j.1365-2966.2010.17434.x . ISSN   0035-8711.
  7. 1 2 Lang, Kenneth R. (2006). Astrophysical formulae. Astronomy and astrophysics library. Vol. 1 (3 ed.). Birkhäuser. ISBN   3-540-29692-1.. The radius (R*) is given by:
  8. 1 2 McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (21 November 2012). "Fundamental parameters and infrared excesses of Hipparcos stars: Parameters and IR excesses from Hipparcos". Monthly Notices of the Royal Astronomical Society. 427 (1): 343–357. arXiv: 1208.2037 . Bibcode:2012MNRAS.427..343M. doi: 10.1111/j.1365-2966.2012.21873.x . ISSN   0035-8711.
  9. 1 2 3 Lyubimkov, L. S.; Rostopchin, S. I.; Lambert, D. L. (21 June 2004). "Surface abundances of light elements for a large sample of early B-type stars – III. An analysis of helium lines in spectra of 102 stars". Monthly Notices of the Royal Astronomical Society. 351 (2): 745–767. Bibcode:2004MNRAS.351..745L. doi: 10.1111/j.1365-2966.2004.07825.x . eISSN   1365-2966. ISSN   0035-8711.
  10. 1 2 Bragança, G. A.; Daflon, S.; Cunha, K.; Bensby, T.; Oey, M. S.; Walth, G. (October 1, 2012). "Projected Rotational Velocities and Stellar Characterization of 350 B Stars in the Nearby Galactic Disk". The Astronomical Journal. 144 (5). American Astronomical Society: 130. arXiv: 1208.1674 . Bibcode:2012AJ....144..130B. doi: 10.1088/0004-6256/144/5/130 . ISSN   0004-6256.
  11. ↑ de Vaucouleurs, A. (August 1, 1957). "Spectral Types and Luminosities of B, A and F Southern Stars". Monthly Notices of the Royal Astronomical Society. 117 (4). Oxford University Press (OUP): 449–462. Bibcode:1957MNRAS.117..449D. doi: 10.1093/mnras/117.4.449 . ISSN   0035-8711.
  12. ↑ Bourgés, L.; Lafrasse, S.; Mella, G.; Chesneau, O.; Bouquin, J. L.; Duvert, G.; Chelli, A.; Delfosse, X. (May 2014). "The JMMC Stellar Diameters Catalog v2 (JSDC): A New Release Based on SearchCal Improvements". Astronomical Data Analysis Software and Systems Xxiii. 485: 223. Bibcode:2014ASPC..485..223B.
  13. ↑ Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (December 2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ....122.3466M. doi: 10.1086/323920 . ISSN   0004-6256.
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