HD 171978

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This article is about e Serpentis. It is not to be confused with ε (epsilon) Serpentis.
HD 171978
Observation data
ICRS
)
Constellation
Serpens
Right ascension 18h 37m 35.9626s[1]
Declination −00° 18′ 34.100″[1]
Apparent magnitude (V) 6.33±0.10 (A)[2]
6.73±0.10 (B)[2]
5.74 to 5.86 (AB)[3]
Characteristics
Spectral type A0V[4]
U−B color index +0.06[5]
B−V color index +0.067±0.010[6]
R−I color index +0.04[5]
Variable type suspected[3]
Distance
537 ± 7 ly
(165 ± 2 pc)
Absolute magnitude (MV)0.30±0.15 (A)[2]
0.70±0.15 (B)[2]
Semi-amplitude
(K1)
(primary)		37.918±0.050 km/s
Semi-amplitude (K2)
(secondary)		38.569±0.076 km/s
Details
Rotational velocity
(v sin i)		5.9±1.0 km/s
PPM 180381[7]
Database references
SIMBADdata

HD 171978 is a

Ursa Major Moving Group.[8]

The binary nature of this system was reported by Canadian astronomer

spectra, indicating their rotation rates are not high. Both are similar A-type main-sequence stars[2] with a combined stellar classification of A0V.[4] In 1970, Geary and Abt noted that the secondary appeared to be an Am star.[8]

References

  1. ^
    doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR
    .
  2. ^
    S2CID 121155872
    .
  3. ^ a b c "NSV 11122, database entry". New Catalogue of Suspected Variable Stars, the improved version. Moscow, Russia: Sternberg Astronomical Institute. Retrieved October 3, 2008.
  4. ^
    Bibcode:1999MSS...C05....0H
    .
  5. ^ a b Hoffleit, D.; Warren, Jr., W. H. HR 6993, database entry (5th Revised ed.). Centre de Données astronomiques de Strasbourg. Retrieved October 3, 2008. {{cite book}}: |work= ignored (help) V/50.
  6. ^
    S2CID 119257644
    .
  7. ^ "e Ser". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2015-12-07.
  8. ^
    doi:10.1086/111013
    .
  9. Bibcode:1948PDAO....7..415P
    .
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