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Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Camelopardalis |
Right ascension | 03h 42m 09.32470s [2] |
Declination | +63° 13′ 00.4977″ [2] |
Apparent magnitude (V) | 5.11 [3] |
Characteristics | |
Spectral type | S3.5/2 (M4III) [3] |
U−B color index | 1.82 [4] |
B−V color index | 1.63 [4] |
R−I color index | 1.39 |
Variable type | Lb [5] |
Astrometry | |
Radial velocity (Rv) | -22.28 [3] km/s |
Proper motion (μ) | RA: -17.27 [2] mas/yr Dec.: 18.94 [2] mas/yr |
Parallax (π) | 6.28 ± 0.34 mas [2] |
Distance | 520 ± 30 ly (159 ± 9 pc) |
Absolute magnitude (MV) | -0.90 |
Orbit [6] | |
Primary | BD Cam A |
Companion | BD Cam B |
Period (P) | 596.2 days |
Eccentricity (e) | 0.088 |
Inclination (i) | 105.6° |
Longitude of the node (Ω) | 162.1° |
Periastron epoch (T) | 2442794.5 |
Argument of periastron (ω) (secondary) | 334.3° |
Details | |
Red giant primary | |
Radius | 135 R☉ |
Luminosity | 185(v)/1600(bol) L☉ |
Surface gravity (log g) | 0.9 cgs |
Temperature | 3250 K |
Metallicity | 0.0 |
Other designations | |
Database references | |
SIMBAD | data |
BD Camelopardalis is an S star and symbiotic star in the constellation Camelopardalis. It is a 5th magnitude star, and is visible to the naked eye under good observing conditions. It was recognized as a spectroscopic binary star in 1922, and its orbital solution published in 1984; [7] it has a 596-day orbital period. A spectroscopic composition analysis was done of the red giant primary star in 1986. [8]
Although the star's spectrum shows the spectral features of zirconium oxide which define spectral class S, BD Cam shows no technetium lines in its spectrum. It is believed to be an "extrinsic" S star, one whose s-process element excesses originate in a binary companion star.
In 1928, Joel Stebbins and Charles Morse Huffer announced that the star, then called HR 1105, is a variable star, based on observations made at Washburn Observatory. [9] It was given its variable star designation, BD Camelopardalis, in 1977. [10] The system displays only minimal variations in the visible, but the presence of the companion and its interactions with the stellar wind of the visible red giant makes for easily observed time-variable spectral features in the ultraviolet and in the near infrared spectral line of helium.
At times BD Cam is the brightest S star in the visible sky, because other bright S stars are Mira variables or other types of variable star with large changes in apparent brightness. Its own brightness variability in the visible part of the spectrum is modest.
On the basis of the measurement of radial velocities of the line components it is concluded that the helium emission originates in the vicinity of the inner Lagrangian point of the system, indicating a gas motion from the red giant primary, directed to the secondary, with a velocity of about 5 km/s. At the same time, there is a high-velocity, hot wind outwards from the primary red giant with a velocity of about 50 km/s.
— Shcherbakov, A. G. and Tuominen, I.
However, HR 1105 appears to have a highly variable UV companion. In 1982, no UV flux was discerned for this system, but by 1986 C IV was strong, increasing by a factor of 3 in 1987 with prominent lines of Si III, C III, O III, Si IV, and N V.
— Ake, Thomas B., III; Johnson, Hollis R. and Perry, Benjamin F., Jr.
Iota Orionis is a multiple star system in the equatorial constellation of Orion the hunter. It is the eighth-brightest member of Orion with an apparent visual magnitude of 2.77 and also the brightest member of the asterism known as Orion's Sword. It is a member of the NGC 1980 open cluster. From parallax measurements, it is located at a distance of roughly 1,340 light-years from the Sun.
Upsilon Sagittarii is a spectroscopic binary star system in the constellation Sagittarius. Upsilon Sagittarii is the prototypical hydrogen-deficient binary (HdB), and one of only four such systems known. The unusual spectrum of hydrogen-deficient binaries has made stellar classification of Upsilon Sagittarii difficult.
Delta Aurigae, Latinized from δ Aurigae, is the Bayer designation for an astrometric binary star in the northern constellation of Auriga. It is visible to the naked eye with an apparent visual magnitude of 3.715. Based upon its annual parallax shift of 23.06 mas, it is some 141 light-years distant from the Earth, give or take a three light-year margin of error. It is drifting further away with a radial velocity of +10 km/s. This star is the namesake for the Delta Aurigids, a meteor shower that occurs between October 6–15. The radiant point for this shower passes several degrees to the south of the star.
CS Camelopardalis is a binary star in reflection nebula VdB 14, in the constellation Camelopardalis. It is a 4th magnitude star, and is visible to the naked eye under good observing conditions.
53 Camelopardalis is a binary star system in the northern circumpolar constellation of Camelopardalis, located 290 light years away from the Sun as determined by parallax measurements. It has the variable star designation AX Camelopardalis; 53 Camelopardalis is the Flamsteed designation. This object is dimly visible to the naked eye as a white hued star with a baseline apparent visual magnitude of +6.02. It is a single-lined spectroscopic binary system with an orbital period of 6.63 years and a high eccentricity of 0.718. The "a sin i" value of the primary is 280 Gm (1.9 AU), where a is the semimajor axis and i is the orbital inclination.
Omicron Cassiopeiae is a triple star system in the constellation Cassiopeia. It is approximately 700 light-years from Earth, based on its parallax. It is visible to the naked eye with a slightly variable apparent magnitude of about 4.5.
2 Centauri is a single star in the southern constellation of Centaurus, located approximately 183 light-years from Earth. It has the Bayer designation g Centauri; 2 Centauri is the Flamsteed designation. This object is visible to the naked eye as faint, red-hued star with an apparent visual magnitude of 4.19. It is moving away from the Earth with a heliocentric radial velocity of +41 km/s. The star is a member of the HR 1614 supercluster.
IK Pegasi is a binary star system in the constellation Pegasus. It is just luminous enough to be seen with the unaided eye, at a distance of about 154 light years from the Solar System.
HR Carinae is a luminous blue variable star located in the constellation Carina. It is surrounded by a vast nebula of ejected nuclear-processed material because this star has a multiple shell expanding atmosphere. This star is among the most luminous stars in the Milky Way. It has very broad emission wings on the Balmer lines, reminiscent from the broad lines observed in the spectra of O and Wolf–Rayet stars. A distance of 5 kpc and a bolometric magnitude of −9.4 put HR Car among the most luminous stars of the galaxy.
PV Telescopii variable is a type of variable star that is established in the General Catalogue of Variable Stars with the acronym PVTEL. This class of variables are defined as "helium supergiant Bp stars with weak hydrogen lines and enhanced lines of He and C". That is, the hydrogen spectral lines of these stars are weaker than normal for a star of stellar class B, while the lines of helium and carbon are stronger. They are a type of extreme helium star.
U Camelopardalis is a semiregular variable star in the constellation Camelopardalis. Based on parallax measurements made by the Hipparcos spacecraft, it is located about 3,000 light-years away from the Earth. Its apparent visual magnitude is about 8, which is dim enough that it cannot be seen with the unaided eye.
48 Persei is a Be star in the constellation Perseus, approximately the 500th brightest of the visible stars in apparent magnitude. It is "well known for its complex spectrum and for its light and velocity variations". The name "48 Persei" is a Flamsteed designation given to it by John Flamsteed in his catalogue, published in 1712.
Omicron1 Orionis is a binary star in the northeastern corner of the constellation Orion. It is visible to the naked eye with an apparent visual magnitude of 4.7. Based upon an annual parallax shift of 5.01±0.71 mas, it is located approximately 650 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an interstellar absorption factor of 0.27 due to intervening dust.
Gamma Phoenicis is a star system in the constellation Phoenix, located around 71.63 parsecs (233.6 ly) distant.
QZ Puppis is a class B2.5V star in the constellation Puppis. Its apparent magnitude is 4.5 and it is approximately 650 light years away based on parallax.
RR Ursae Minoris, abbreviated RR UMi, is a binary star system in the northern circumpolar constellation of Ursa Minor. It can be viewed with the naked eye, typically having an apparent visual magnitude of around 4.710. Based upon an annual parallax shift of 7.1 mas as seen from Earth's orbit, it is located 460 light years away. The system is moving further from the Sun with a heliocentric radial velocity of +6 km/s.
31 Cygni, also known as ο1 Cygni, Omicron1 Cygni, ο2 Cygni or V695 Cygni, is a ternary star system about 750 light years away in the constellation Cygnus.
HR 6819, also known as HD 167128 or QV Telescopii, is a double star system in the southern constellation of Telescopium. It is in the south-western corner of the constellation, near Pavo to the south and Ara to the west. The system appears as a variable star that is dimly visible to the naked eye with an apparent magnitude that ranges from 5.32 down to 5.39, which is comparable to the maximum brightness of the planet Uranus. It is about 1,120 light years from the Sun, and is drifting farther away at a rate of 9.4 km/s. Due to its location in the sky, it is visible only to observers south of 33°N latitude.
HD 26755, also known as HR 1313, is a spectroscopic binary located in the northern circumpolar constellation Camelopardalis, the giraffe. It has an apparent magnitude of 5.72, making it faintly visible to the naked eye under ideal conditions. Gaia DR3 parallax measurements place the system at a distance of 271 light years and is currently drifitng closer with a heliocentric radial velocity of −38 km/s. At its current distance, HD 26755's brightness is diminished by 0.19 magnitudes due to interstellar dust.
HD 39118 is a spectroscopic binary star in the constellation Orion, close to the celestial equator. It is made up from three stars: a cool primary and a hot secondary, which is a binary star formed from a B-type main-sequence star and an A-type main-sequence star. A 2021 estimate derive a distance of 708 parsecs (2,310 ly) to HD 39118, and it is moving away from Earth at a speed of 4.24 km/s. The apparent magnitude is 5.976, making it visible to the naked eye only from dark skies.