Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Dorado |
Right ascension | 05h 28m 44.8489s [1] |
Declination | −65° 26′ 54.946″ [1] |
Apparent magnitude (V) | 6.98−7.06 [2] / 13.0 [3] |
Characteristics | |
AB Dor AC | |
Spectral type | K0V [4] + M8 |
U−B color index | +0.37 |
B−V color index | +0.86±0.02 [2] |
Variable type | Flare star |
AB Dor B | |
Spectral type | M5 + M5-6 [5] |
Astrometry | |
Radial velocity (Rv) | 32.40 ± 2.2 [6] km/s |
Proper motion (μ) | RA: 33.16 [7] mas/yr Dec.: 150.83 [7] mas/yr |
Parallax (π) | 65.93 ± 0.57 mas [7] |
Distance | 49.5 ± 0.4 ly (15.2 ± 0.1 pc) |
Absolute magnitude (MV) | 5.86 [8] |
Orbit [5] | |
Primary | AB Dor Ba |
Companion | AB Dor Bb |
Period (P) | 0.986 ± 0.008 yr |
Semi-major axis (a) | 0.052 ± 0.002″ |
Eccentricity (e) | 0.6 ± 0.1 |
Inclination (i) | 121 ± 5° |
Longitude of the node (Ω) | 270 ± 15° |
Periastron epoch (T) | 2003.68 ± 0.05 |
Argument of periastron (ω) (secondary) | 54 ± 20° |
Orbit [9] | |
Primary | AB Dor A |
Companion | AB Dor C |
Period (P) | 12.895 yr |
Semi-major axis (a) | 0.304″ |
Eccentricity (e) | 0.281 |
Inclination (i) | 63.0° |
Longitude of the node (Ω) | 159.2° |
Periastron epoch (T) | B 1991.822 |
Argument of periastron (ω) (secondary) | 157.3° |
Details | |
AB Dor A | |
Mass | 0.86 [10] M☉ |
Radius | 0.96±0.06 [10] R☉ |
Temperature | 5,250 [11] K |
Rotation | 0.5148 days [11] |
Age | 50 [12] Myr |
AB Dor C | |
Mass | 0.090±0.008 [13] M☉ |
Age | 25–120 [13] Myr |
AB Dor Ba | |
Mass | 0.28 ± 0.05 [5] M☉ |
AB Dor Bb | |
Mass | 0.25 ± 0.05 [5] M☉ |
Other designations | |
Database references | |
SIMBAD | data |
ARICNS | data |
AB Doradus is a pre-main-sequence quadruple [5] star system in the constellation Dorado. The primary is a flare star that shows periodic increases in activity.
The primary star in this system spins at a rate 50 times that of the Sun, and consequently has a strong magnetic field. [15] It has a greater number of star spots than the Sun. These can cause the luminosity of the star to appear to vary over each orbital cycle. Measurements of the spin rate of this star at its equator have shown that it varies over time due to the effect of this magnetic field. [16]
The system has four components consisting of a pair of binary star systems separated by an angle of about 9″. [5] The binary star AB Doradus Ba/Bb orbits the primary AB Doradus A at an average distance of 135 astronomical units (AUs). AB Doradus C is a closer in companion that orbits the primary at a distance of 5.1 AU, and has an orbital period of 11.75 years.
AB Doradus C is among the lowest-mass stars ever found. At an estimated mass 93 times Jupiter's, it is near the limit of 75–83 Jupiter masses below which it would be classified as a brown dwarf. [17] However, recent evidence indicates that the star may actually be a binary system itself, consisting of two brown dwarfs, AB Doradus Ca/Cb, with 72 and 13 Jupiter masses, respectively. [18]
This system is a member of the eponymous AB Doradus Moving Group, a loose stellar association of about 30 stars that are all approximately the same age and moving in the same general direction. [19] It is likely that all of these stars formed in the same giant molecular cloud.
HR 7703 is a binary star system in the constellation of Sagittarius. The brighter component has an apparent visual magnitude of 5.31, which means it is visible from suburban skies at night. The two stars are separated by an angle of 7.10″, which corresponds to an estimated semimajor axis of 56.30 AU for their orbit.
Iota Trianguli Australis is a binary star system in the constellation Triangulum Australe. It is visible to the naked eye with a combined apparent visual magnitude of +5.27. Based upon an annual parallax shift of 25.77 mas as seen from the Earth, it is located around 127 light years from the Sun. The system appears to be moving closer to the Sun with a radial velocity of around −6 km/s.
Pi1 Ursae Minoris is a common proper motion binary star system in the northern circumpolar constellation of Ursa Minor. The pair have apparent visual magnitudes of +6.58 and +7.31, with a combined magnitude of 6.1. They are located about 71 light years from the Sun. The two have an angular separation of 31.4 arc seconds, which corresponds to a physical separation of about 680 AU, and orbit each other with a period of about 13,100 years.
9 Aurigae is a star system in Auriga (constellation). It has an apparent magnitude of about 5, making it visible to the naked eye in many suburban skies. Parallax estimates made by the Hipparcos spacecraft put it at about 86 light-years from the solar system, although individual Gaia Data Release 3 parallaxes place all three components at 88 light years.
3 Centauri is a triple star system in the southern constellation of Centaurus, located approximately 300 light years from the Sun. It is visible to the naked eye as a faint, blue-white hued star with a combined apparent visual magnitude of 4.32. As of 2017, the two visible components had an angular separation of 7.851″ along a position angle of 106°. The system has the Bayer designation k Centauri; 3 Centauri is the Flamsteed designation. It is a suspected eclipsing binary with a variable star designation V983 Centauri.
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δ Doradus is a star in the southern constellation of Dorado. Based upon an annual parallax shift of 21.80 mas as seen from Earth, it is located around 150 light years from the Sun. The star is visible to the naked eye with an apparent visual magnitude of +4.34.
Zeta Doradus, Latinized from ζ Doradus, is a young star system that lies approximately 38 light-years away. The system consists of two widely separated stars, with the primary being bright enough to be observed with the naked eye but the secondary being much a much fainter star that requires telescopic equipment to be observed.
AB Doradus Moving Group is a group of about 30 associated stars that are moving through space together with the star AB Doradus. A moving group is distinguished by its members having about the same age, composition and motion through space. Hence they most likely formed in the same location.
HD 225218 is a quadruple star system in the northern constellation of Andromeda. The primary component, HD 225218 A, is a giant star with a stellar classification of B9III, an apparent magnitude of 6.16, and is a candidate Lambda Boötis star. It has a fainter, magnitude 9.65 companion, HD 225218 B, at an angular separation of 5.2″ along a position angle of 171°. The primary itself has been identified as a binary star system through interferometry, with the two components separated by 0.165″. The pair, HD 225218 Aa and Ab, orbit each other with a period of about 70 years and an eccentricity of 0.515. Component B is likewise a spectroscopic binary.
V429 Geminorum (BD+20°1790) is a young orange dwarf star in the constellation Gemini, located 90 light years away from the Sun. It is a BY Draconis variable, a cool dwarf which varies rapidly in brightness as it rotates.
HD 16754 is a binary or triple-star system in the constellation Eridanus. It has the Bayer designation s Eridani; HD 16754 is the designation from the Henry Draper catalogue. The system is visible to the naked eye as a faint point of light with an apparent visual magnitude of +4.74. It is located at a distance of approximately 132 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +18 km/s. The system is a member of the Columba association of co-moving stars.
Tau1 Hydrae is a triple star system in the equatorial constellation of Hydra. Based upon the annual parallax shift of the two visible components as seen from Earth, they are located about 18 parsecs (59 ly) from the Sun. The system has a combined apparent visual magnitude of +4.59, which is bright enough to be visible to the naked eye at night.
HD 106515 is a binary star in the constellation of Virgo.
HD 41742/41700 is a star system that lies approximately 88 light-years away in the constellation of Puppis. The system consists of two bright stars where the primary is orbited by two fainter stars, making it a quadruple with an unequal hierarchy.
50 Persei is a star in the constellation Perseus. Its apparent magnitude is 5.52, which is bright enough to be seen with the naked eye. Located around 21.00 parsecs (68.5 ly) distant, it is a White main-sequence star of spectral type F7V, a star that is currently fusing its core hydrogen. In 1998 the star was named a candidate Gamma Doradus variable with a period of 3.05 days, which would means it displays variations in luminosity due to non-radial pulsations in the photosphere. Subsequently, it was classified as a RS Canum Venaticorum and BY Draconis variable by an automated program.
DS Tucanae is a binary star system 144 light years away in the constellation of Tucana. It has an apparent visual magnitude of 8.5, and is a RS Canum Venaticorum variable. The system is notable for being young as a member of the 45 Myr old Tucana-Horologium moving group and for the primary star hosting the confirmed exoplanet DS Tucanae Ab, discovered by THYME, using TESS.
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