HD 171978

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
HD 171978
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Serpens
Right ascension 18h 37m 35.9613s[1]
Declination −00° 18′ 34.100″[1]
Apparent magnitude (V) 5.74 to 5.86[2]
Spectral type A1V / A1V
(spectroscopic binary)[3]
U−B color index +0.06[3]
B−V color index +0.07[3]
R−I color index +0.04[3]
Radial velocity (Rv)11.415±0.031[4][5] km/s
Proper motion (μ) RA: 11.74[1] mas/yr
Dec.: −19.83[1] mas/yr
Parallax (π)5.06 ± 0.93[1] mas
Distanceapprox. 600 ly
(approx. 200 pc)
Absolute magnitude (MV)−0.26[6]
Period (P)14.684636±0.000029 d
Eccentricity (e)0.2495±0.0011
Periastron epoch (T)2454405.073±0.011
Argument of periastron (ω)
Semi-amplitude (K1)
37.918±0.050 km/s
Semi-amplitude (K2)
38.569±0.076 km/s
Other designations
e Ser, BD−00 3521, FK5 3480, GC 25456, HIP 91322, HR 6993, PPM 180381, SAO 142444.[1]
Database references

The star HD 171978 is a spectroscopic binary in the constellation of Serpens. It consists of two A-type main sequence stars orbiting each other with a period of approximately 14.7 days.[4] The overall apparent visual magnitude of the system varies between 5.74 and 5.86.[2]


  1. ^ a b c d e f NSV 11122 -- Spectroscopic binary, database entry, SIMBAD. Accessed on line October 3, 2008.
  2. ^ a b NSV 11122, database entry, New Catalogue of Suspected Variable Stars, the improved version, Sternberg Astronomical Institute, Moscow, Russia. Accessed on line October 3, 2008.
  3. ^ a b c d HR 6993, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line October 3, 2008.
  4. ^ a b c Fekel, Francis C.; Tomkin, Jocelyn; Williamson, Michael H. (2013). "New Precision Orbits of Bright Double-lined Spectroscopic Binaries. VIII. HR 1528, HR 6993, 2 Sagittae, and 18 Vulpeculae". The Astronomical Journal. 146 (5). 129. Bibcode:2013AJ....146..129F. doi:10.1088/0004-6256/146/5/129.
  5. ^ Figure is for the barycenter of the spectroscopic binary system.
  6. ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971 [astro-ph.GA], Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015. Cite uses deprecated parameter |class= (help)