Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Perseus |
Right ascension | 04h 48m 53.348s [2] |
Declination | 43° 16′ 32.09″ [2] |
Apparent magnitude (V) | 7.70 [3] |
Characteristics | |
Spectral type | A5Iap [4] + B2/3Ia/Ib [5] |
B−V color index | 0.423±0.019 [3] |
Variable type | Semiregular [6] |
Astrometry | |
Proper motion (μ) | RA: 1.600 mas/yr [2] Dec.: −1.781 mas/yr [2] |
Parallax (π) | 0.1004 ± 0.0414 mas [2] |
Distance | < 3,200 ly (< 1,000 [7] pc) |
Absolute magnitude (MV) | −3.3 [7] |
Orbit [8] | |
Period (P) | 360.47±1.07 d |
Semi-major axis (a) | ≥243 ± 8 Gm (1.624 ± 0.053 AU) |
Eccentricity (e) | 0.28±0.03 |
Periastron epoch (T) | 2,435,141.74±5.06 JD |
Argument of periastron (ω) (secondary) | 268.4±4.8° |
Semi-amplitude (K1) (primary) | 51.4±1.6 km/s |
Details | |
Supergiant | |
Mass | 1.0 (assumed) [9] M☉ |
Luminosity | 2,000 [7] L☉ |
Surface gravity (log g) | 2.0±0.5 [7] cgs |
Temperature | 9,500±300 [7] K |
Metallicity [Fe/H] | −0.73±0.10 [10] dex |
Companion | |
Mass | 5 (times the primary mass) [9] M☉ |
Temperature | 12,500 [9] K |
Other designations | |
Database references | |
SIMBAD | data |
KS Persei is a binary system in the equatorial constellation of Perseus. It is sometimes known as Bidelman's Star, named after William P. Bidelman. [11] [3] The star is invisible to the naked eye with a mean apparent visual magnitude of 7.70. [3] As of 2018, the structure and evolutionary history of this system remain uncertain, although some form of mass transfer is likely to have occurred to explain the observed properties. [12]
The peculiar nature of the spectra for this star was noted in the Henry Draper Catalogue and was the subject of a study by W. P. Bidelman published in 1950. He found extremely weak lines of hydrogen, similar to those for Upsilon Sagittarii but at a lower temperature. The data strongly suggested the star has an abnormally low abundance of hydrogen in the stellar atmosphere. Bidelman noted that the radial velocity of the star is variable, demonstrating that it has an unseen companion. [13] Preliminary orbital elements for this single-lined spectroscopic binary were published in 1955 by J. F. Heard and O. Boshko, giving an orbital period of 359.7 days and with eccentricity of 0.27. They found a large mass function of 4.5, suggesting that the supergiant has lost mass and the companion is relatively massive. [14] The mass function was revised to 3.6±0.4 in 1988, suggesting the secondary is five times more massive than the primary. [7] Although the Gaia parallax is small (and the Hipparcos parallax is negative), KS Persei is thought to be less than 1,000 pc away. Older studies have suggested distances up to 3,900 pc. [7]
An analysis by G. Wallerstein and associates in 1967 showed that nitrogen is the second most abundant element in the primary, likely as a result of carbon cycling. [15] G. A. Bakos attempted to photometrically detect an eclipse but was unsuccessful. However, he did tentatively detect semiregular variation with a period of ~30 days and an amplitude of 0.1 magnitude. This variability was confirmed by K. Morrison and G. P. H. Willingale in 1987, and they discovered an additional five day cycle. [16] In 1982, J. S. Drilling and D. Schönberner detected a hot companion from spectra collected by the International Ultraviolet Explorer. [5] The system is an infrared source, and models of the infrared flux suggest it is being emitted by circumstellar dust heated to 1,100 K. [7] It is possible that the companion is obscured by dust. [9]
Epsilon Cancri is a white-hued binary star system in the zodiac constellation of Cancer. It is the brightest member of the Beehive Cluster with an apparent visual magnitude of +6.29, which is near the lower limit of visibility with the naked eye. The annual parallax shift of 5.4 mas as seen from Earth yields a distance estimate of approximately 606 light-years from the Sun.
HD 125823, also known as V761 Centauri or a Centauri, is a variable star in the constellation Centaurus. It is a blue-white star that is visible to the naked eye with a mean apparent visual magnitude of +4.41. The distance to this star is approximately 460 light years based on parallax measurements. It is a member of the Upper Centaurus–Lupus subgroup of the Scorpius–Centaurus association.
Gamma Persei is a binary star system in the constellation Perseus. The combined apparent visual magnitude of the pair is +2.9, making it the fourth-brightest member of the constellation. The distance to this system is of roughly 221 light-years with a 1% margin of error. About 4° to the north of Gamma Persei is the radiance point for the annual Perseid meteor shower.
Delta Persei is a double star in the northern constellation of Perseus. It has an apparent visual magnitude of 3.01, making it readily visible with the naked eye. Parallax measurements give it a distance of about 520 light-years from the Earth.
HD 195019 is a binary star system in the northern constellation of Delphinus. The brighter star has a close orbiting exoplanet companion. This system is located at a distance of 122 light years from the Sun based on parallax measurements, but it is drifting closer with a radial velocity of −91.3 km/s. Although it has an absolute magnitude of 4.01, at that distance the system is considered too faint to be viewed with the naked eye, having a combined apparent visual magnitude of 6.87. However, it should be readily visible with a pair of binoculars or a small telescope.
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.
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.
PV Telescopii, also known as HD 168476, is a variable star in the southern constellation of Telescopium. It is too dim to be visible to the naked eye, having an apparent visual magnitude that has been measured varying from 9.24 down to 9.40. The star is the prototype of a class of objects called PV Telescopii variables. It is located at an estimated distance of approximately 23 kilolight-years from the Sun, but is drifting closer with a radial velocity of −169 km/s.
Psi Persei is a single Be star in the northern constellation of Perseus. It has an apparent visual magnitude of about 4.2, so it is visible to the naked eye at night under suitably dark skies. Based on parallax measurements, it is located at a distance of roughly 580 light-years from the Earth.
HD 21278 is a binary star system in the constellation Perseus, located within the 60±7 million year old Alpha Persei Cluster. It has a blue-white hue and is visible to the naked eye with a combined apparent visual magnitude of 4.99. The system is located at a distance of approximately 580 light years from the Sun based on parallax, and it is drifting further away with a radial velocity of +1.20 km/s.
42 Persei is a binary star system in the northern constellation of Perseus. It has the Bayer designation n Persei, while 42 Persei is the Flamsteed designation. The system is visible to the naked eye as a dim, white-hued point of light with an apparent visual magnitude of 5.11. It is located around 93 parsecs (302 ly) distant from the Sun, but is drifting closer with a radial velocity of −12.4 km/s.
31 Persei is a single star in the northern constellation of Perseus. It is visible to the naked eye as a dim, blue-white hued point of light with an apparent visual magnitude of 5.05. This star is located around 172 parsecs (560 ly) away from the Sun, and it is drifting closer with a radial velocity of −1.6 km/s. It is likely a member of the Alpha Persei Cluster.
2 Persei is a binary star system in the northern constellation Perseus, located around 500 light years away from the Sun. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude is 5.70. The system is moving further away from the Earth with a heliocentric radial velocity of 11 km/s.
3 Persei is a single, orange-hued star in the northern constellation of Perseus. It is dimly visible to the naked eye under good viewing conditions, having an apparent visual magnitude of 5.70 The star is located around 79 parsecs (257 ly) distant, based upon an annual parallax shift of 12.7 mas.
56 Persei is at least a triple star and possibly a quadruple star system in the northern constellation of Perseus. It is visible to the naked eye as a dim point of light with a combined apparent visual magnitude of 5.77. The system is located 139 light-years (42.5 pc) distant from the Sun based on parallax, but is drifting closer with a radial velocity of −32 km/s.
HD 137509 is a star in the southern constellation of Apus, positioned less than a degree from the northern constellation boundary with Triangulum Australe. It has the variable star designation of NN Apodis, or NN Aps for short, and ranges in brightness from an apparent visual magnitude of 6.86 down to 6.93 with a period of 4.4916 days. The star is located at a distance of approximately 647 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +0.50 km/s.
V520 Persei is a blue supergiant member of NGC 869, one of the Perseus Double Cluster open clusters. It is an irregular variable star. At a magnitude of 6.55, V520 Persei is the brightest member in either NGC 869 or NGC 884, although the brighter HD 13994 lies in the foreground along the same line of sight.
HD 21071 is a blue-white hued variable star in the northern constellation of Perseus. Also known as V576 Persei, it is a sixth magnitude star that is dimly visible to the naked eye under good viewing conditions, having an apparent visual magnitude of 6.09. The brightness of the star varies with a multiperiodic cycle. The distance to HD 21071, as determined from an annual parallax shift of 6.1 mas, is 535 light years. It is a member of the young Alpha Persei cluster, Melotte 20, and moving is closer to the Earth with a heliocentric radial velocity of −1.5 km/s.
17 Comae Berenices is a multiple star system in the northern constellation of Coma Berenices. The brighter component, 17 Com A, is a naked eye star with an apparent visual magnitude of 5.2. It has a faint companion of magnitude 6.6, 17 Com B, positioned at an angular separation of 146.4″ along a position angle of 251°, as of 2018. They are located at a distance of approximately 240 light years from the Sun based on parallax measurements.
HD 72945 and HD 72946 form a co-moving star system in the northern constellation of Cancer. HD 72945 is a binary star that is dimly visible to the naked eye as a point of light with an apparent visual magnitude of 5.91. At an angular separation of 10.10″ is the fainter companion star HD 72946 at magnitude 7.25. It is being orbited by a brown dwarf. The system as a whole is located at a distance of approximately 84 light years from the Sun based on parallax measurements.