Observation data Epoch J2000.0 Equinox J2000.0 (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] |
Astrometry | |
Radial velocity (Rv) | +11.415±0.031 [2] km/s |
Proper motion (μ) | RA: +14.018 [1] mas/yr Dec.: −20.710 [1] mas/yr |
Parallax (π) | 6.0774 ± 0.0833 mas [1] |
Distance | 537 ± 7 ly (165 ± 2 pc) |
Absolute magnitude (MV) | 0.30±0.15 (A) [2] 0.70±0.15 (B) [2] |
Orbit [2] | |
Period (P) | 14.684636±0.000029 d |
Eccentricity (e) | 0.2495±0.0011 |
Periastron epoch (T) | 2,454,405.073±0.011 |
Argument of periastron (ω) (secondary) | 230.90±0.30° |
Semi-amplitude (K1) (primary) | 37.918±0.050 km/s |
Semi-amplitude (K2) (secondary) | 38.569±0.076 km/s |
Details [2] | |
A | |
Mass | 2.5 M☉ |
Radius | 3.4±0.3 R☉ |
Luminosity | 60.5±8.5 L☉ |
Rotational velocity (v sin i) | 5.6±1.0 km/s |
B | |
Mass | 2.35 M☉ |
Radius | 2.8±0.2 R☉ |
Luminosity | 41.9±5.9 L☉ |
Rotational velocity (v sin i) | 5.9±1.0 km/s |
Other designations | |
Database references | |
SIMBAD | data |
HD 171978 is a binary star system in the Serpens Cauda segment of the equatorial constellation of Serpens. It may be referred to by its Bright Star Catalogue identifier of HR 6993. This system is dimly visible to the naked eye with a combined apparent visual magnitude of 5.76, [6] although is a suspected variable star of unknown type with a magnitude that has been reported to vary between 5.74 and 5.86. [3] HD 171978 is located at a distance of approximately 537 light-years from the Sun based on parallax, [1] and is drifting further away with a barycentric radial velocity of +11.4 km/s. [2] It is a member of the Ursa Major Moving Group. [8]
The binary nature of this system was reported by Canadian astronomer R. M. Petrie in 1948. [9] It is a double-lined spectroscopic binary with an orbital period of 14.7 days and an eccentricity (ovalness) of 0.25. The orbital inclination is estimated to be ~30°. The two stars have a magnitude difference of 0.4±0.1 mag, which gives respective magnitudes of 6.33 and 6.73. They each show a sharp-lined 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]
47 Andromedae is a binary star system in the northern constellation of Andromeda. The designation is from the star catalogue of John Flamsteed, first published in 1712. The system has a combined apparent visual magnitude of 5.60, which is just bright enough to be faintly visible to the naked eye under good seeing conditions. The distance to this system, as determined from an annual parallax shift of 15.9805 mas, is about 204 light years. It is moving away from the Sun with a heliocentric radial velocity of +13.3 km/s.
6 Andromedae is an astrometric binary star system in the northern constellation of Andromeda. The designation comes from the star catalogue of John Flamsteed, first published in 1712. Its apparent visual magnitude is 5.91, which is just bright enough to be visible to the naked eye under good seeing conditions. Based upon an annual parallax shift of 34.1 mas as seen from Earth, it is around 96 light years from the Sun. It is moving closer to the Sun with a radial velocity of −32.4 km/s. The system has a relatively high proper motion, advancing across the celestial sphere at the rate of 0.272 arc seconds per annum.
32 Aquarii is a binary star system in the zodiac constellation of Aquarius. 32 Aquarii is its Flamsteed designation. It is visible to the naked eye as a dim, white-hued star with an apparent visual magnitude of 5.29. This system is moving away from the Earth with a heliocentric radial velocity of +19 km/s, and is a possible member of the corona of the Ursa Major flow.
58 Aquarii, abbreviated 58 Aqr, is a star in the constellation of Aquarius. 58 Aquarii is its Flamsteed designation. It is a sixth magnitude star with an apparent visual magnitude of 6.39, which means it is a challenge to view with the naked eye. Based upon an annual parallax shift of 13.4 mas, it is located 243 light years from the Sun. This has been identified as a visual binary system with an orbital period of 829.976 days in a circular orbit.
22 Camelopardalis is a binary star system in the northern circumpolar constellation of Camelopardalis, located 212 light years away from the Sun. It has an apparent visual magnitude of 7.03, which is below the normal limit for visibility with the naked eye. This object is moving further from the Earth with a mean heliocentric radial velocity of +10 km/s. Eggen (1991) listed it as a member of the IC 2391 supercluster. It has also been catalogued as a member of the Hyades group. However, Griffin (2005) suggests it belongs to neither.
HD 172044 is a triple star system in the northern constellation of Lyra. It has a blue-white hue and is visible to the naked eye with an apparent visual magnitude of 5.41. The distance to the primary component is approximately 535 light years based on parallax. It is drifting closer with a radial velocity of −32.5 km/s, and is predicted to come as near as 77.3 light-years to the Sun some 4.5 million years from now.
ET Andromedae is a binary star system star in the northern constellation of Andromeda. It has an apparent visual magnitude of 6.48, placing it at the nominal limit for visibility with the naked eye. The distance to this system can be estimated from its annual parallax shift of 5.42 mas, which yields a value of 602 light years.
DV Aquarii is a binary star system in the zodiac constellation of Aquarius. It has a peak apparent visual magnitude of 5.89, which is bright enough to be visible to the naked eye. The distance can be estimated from its annual parallax shift of 11.2 mas, yielding a separation of 291 light years.
V923 Aquilae is a variable binary star system in the equatorial constellation of Aquila. It has the designation HD 183656 from the Henry Draper Catalogue; V932 Aql is the variable star designation. The system is dimly visible to the naked eye with an apparent visual magnitude that fluctuates around 6.06. It is located at a distance of approximately 890 light years from the Sun based on parallax, but is drifting closer with a radial velocity of around −26 km/s.
HD 30453 is a binary star system in the northern constellation of Auriga. It is visible to the naked eye with an apparent visual magnitude of 5.86. The system is located at a distance of approximately 334 light years from the Sun based on parallax. It is drifting further away from the Sun with a radial velocity of 16.65 km/s.
18 Vulpeculae is a binary star system in the northern constellation of Vulpecula, located about 489 light years away from the Sun. It is visible to the naked eye as a faint, white-hued star with a combined apparent visual magnitude of 5.51. The system is moving closer to the Earth with a heliocentric radial velocity of −11.7 km/s.
HD 44780 is a binary star system in the northern constellation of Gemini, located about 3° north of Mu Geminorum. The pair have a combined apparent visual magnitude of 6.35, which is near the lower limit of visibility to the naked eye. Although it is above magnitude 6.5, it was not included in the Bright Star Catalogue; the designation HD 44780 comes from the Henry Draper catalogue. Based upon parallax measurements, the system is located at a distance of approximately 960 light years from the Sun. It is drifting further away with a radial velocity of +17 km/s.
ν Ceti, Latinized as Nu Ceti, is a binary star system in the equatorial constellation of Cetus. It is visible to the naked eye as a faint point of light with a combined apparent visual magnitude of 4.86. The system is located approximately 340 light years distant from the Sun, based on parallax, and is drifting further away with a radial velocity of 4.8 km/s. Nu Ceti is believed to be part of the Ursa Major stream of co-moving stars.
μ Cygni, Latinised as Mu Cygni, is a binary star system in the northern constellation of Cygnus. It is visible to the naked eye as a faint point of light with a combined apparent visual magnitude of 4.49. The system is located 72 light years distant from the Sun, based on parallax, and is drifting further away with a radial velocity of +17 km/s.
HR 4072 is a binary star system in the northern circumpolar constellation of Ursa Major. It has the variable star designation ET Ursae Majoris, abbreviated ET Uma, while HR 4072 is the system's designation from the Bright Star Catalogue. It has a white hue and is faintly visible to the naked eye with an apparent visual magnitude that fluctuates around 4.94. The system is located at a distance of approximately 339 light years from the Sun based on parallax measurements. The radial velocity measurement is poorly constrained, but it appears to be drifting closer to the Sun at the rate of around −3 km/s.
31 Cygni, also known as ο1 Cygni, Omicron1 Cygni, or V695 Cygni, is a triple star system about 750 light years away in the constellation Cygnus.
HD 2421 is a multiple star system in the constellation Andromeda. It is faintly visible to the naked eye with a combined apparent visual magnitude of 5.17. Based on parallax measurements, it is located at a distance of approximately 290 light years from the Sun. The system is drifting further away with a radial velocity of ~2 km/s.
HD 112014 is a star system in the northern constellation of Camelopardalis. It is dimly visible as a point of light with an apparent visual magnitude of 5.92. The distance to this system is approximately 415 light years based on parallax measurements.
HD 136138, or HR 5692, is a binary star system in the Serpens Caput segment of the Serpens constellation. It has a golden hue like the Sun and is dimly visible to the naked eye with an apparent visual magnitude of 5.68; the light contribution from the companion is effectively negligible. This system is located at a distance of approximately 420 light years from the Sun based on parallax. It is drifting closer with a radial velocity of −7.7 km/s and has a proper motion of 23.5 mas·yr−1.
HD 1, also known as HIP 422, is the first star catalogued in the Henry Draper Catalogue. It is located in the northern circumpolar constellation Cephus and has an apparent magnitude of 7.42, making it readily visible in binoculars, but not to the naked eye. The object is located relatively far away at a distance of 1,220 light years but is approaching the Solar System with a spectroscopic radial velocity of −27.3 km/s.
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