HD 196775

HD 196775
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Delphinus
Right ascension 20h 39m 04.9681s[1]
Declination +15° 50′ 17.5112″[1]
Apparent magnitude (V) 5.98[2]
Characteristics
Spectral type B3 V[3]
U−B color index −0.71[2]
B−V color index −0.16[2]
Astrometry
Radial velocity (Rv)−4.6±1[4] km/s
Proper motion (μ) RA: −0.868 mas/yr[1]
Dec.: −15.290 mas/yr[1]
Parallax (π)3.1211 ± 0.0617 mas[1]
Distance1,050 ± 20 ly
(320 ± 6 pc)
Absolute magnitude (MV)−2.05[5]
Details
Mass7±0.4[6] M☉
Radius4.13±0.14[7] R☉
Luminosity1,507[8] L☉
Surface gravity (log g)3.97[9] cgs
Temperature18,100[9] K
Rotational velocity (v sin i)145±6[10] km/s
Age36.1±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
SIMBADdata

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,[3] 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]
Companion mv PA (°) Year Sep. (″)
B 12.40 154 2006 5.2
C 11.31 122 2012 39.9
D 14.40 146 2012 28.8
E 14.40 33 2012 23.3
  1. ^ a b c d Cite error: The named reference EDR3 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference Oja1984 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Cucchiaro1980 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  6. ^ a b c d e Cite error: The named reference Tetzlaff2011 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Lang2006 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference McDonald2012 was invoked but never defined (see the help page).
  9. ^ a b c Cite error: The named reference Lyubimkov2004 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Bragança2012 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference deVaucouleurs was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Bourges2014 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Mason2001 was invoked but never defined (see the help page).