![]() HD 87643 is embedded in the faint nebulosity at the centre of this image. The red arc is NGC 3199, a Wolf–Rayet nebula around WR 18. | |
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Carina |
Right ascension | 10h 04m 30.2840s [1] |
Declination | −58° 39′ 52.091″ [1] |
Apparent magnitude (V) | 8.87 [2] (7.4 - 9.8 [3] ) |
Characteristics | |
Spectral type | B3 I[e] [4] |
U−B color index | −0.54 [2] |
B−V color index | +0.69 [2] |
Variable type | INA [3] |
Astrometry | |
Proper motion (μ) | RA: −7.557 [1] mas/yr Dec.: +5.438 [1] mas/yr |
Parallax (π) | 0.6293 ± 0.1227 mas [1] |
Distance | approx. 5,000 ly (approx. 1,600 pc) |
Absolute magnitude (MV) | −4.1 [5] |
Details | |
Mass | 25 [6] M☉ |
Luminosity | 41,000 [7] L☉ |
Temperature | 17,000 [7] K |
Other designations | |
Database references | |
SIMBAD | data |
HD 87643 is a B[e] class binary star embedded in a reflection nebula.
The system is described as having "one of the most extreme infrared excesses for this object class". It harbours a large amount of both hot and cold dust, and is surrounded by a debris disk with radius 2.5-3 AU [6] and an extended reflection nebula. and is important for astronomers in their study of stellar formation. [8]
All the properties of HD 87643 are highly uncertain. Its distance has been estimated anywhere from one to six kpc. The General Catalogue of Variable Stars classifies it as an Orion variable, a pre-main sequence star, but other authors consider it to be a supergiant B[e] star. It has been confirmed to be a binary star system with the two stars separated by about 52 AU, but the nature of the companion is unknown. [8]
Kappa Boötis is a double star in the constellation Boötes. It has the traditional name Asellus Tertius and the Flamsteed designation 17 Boötis. The components are separated by an angular distance of 13.5 arcsec, viewable in a small telescope. Kappa Boötis is approximately 155 light years from Earth.
Theta1 Orionis C is a member of the Trapezium open cluster that lies within the Orion Nebula. The star C is the most massive of the four bright stars at the heart of the cluster. It is an O class blue main sequence star with a B-type main sequence companion. Its high luminosity and large distance give it an apparent visible magnitude of 5.1.
CS Camelopardalis is a binary star in reflection nebula VdB 14, in the constellation Camelopardalis.
V533 Carinae is a white A-type supergiant variable star with a mean apparent magnitude of +4.59 in the constellation Carina. It is over 10,000 light years from Earth.
Y Carinae is a Classical Cepheid variable, a type of variable star, in the constellation Carina. Its apparent magnitude varies from 7.53 to 8.48.
R Coronae Australis is a variable binary system in the constellation Corona Australis. It has varied between magnitudes 10 and 14.36. A small reflection/emission nebula NGC 6729 extends from the star towards SE. It is also the brightest feature of the Coronet Cluster, therefore sometimes called R CrA Cluster.
EZ Canis Majoris is binary system in the constellation of Canis Major. The primary is a Wolf-Rayet star and it is one of the ten brightest Wolf-Rayet stars, brighter than apparent magnitude 7.
HD 97048 or CU Chamaeleontis is a Herbig Ae/Be star 603 ly away in the constellation Chamaeleon. It is a variable star embedded in a dust cloud containing a stellar nursery, and is itself surrounded by a dust disk.
FK Comae Berenices is a variable star that varies in apparent magnitude between 8.14 and 8.33 over a period of 2.4 days. It is the prototype for the FK Comae Berenices class of variable stars. The variability of FK Com stars may be caused by large, cool spots on the rotating surfaces of the stars. This star is thought to be the result of a recent binary merger, resulting in a high rate of both spin and magnetic activity.
89 Herculis is a binary star system located about 4,700 light years away from the Sun in the northern constellation of Hercules. It is visible to the naked eye as a faint, fifth magnitude star. The system is moving closer to the Earth with a heliocentric radial velocity of −28.5 km/s.
HD 110432 is a Be star in the south-east of Crux, behind the center of the southern hemisphere's dark Coalsack Nebula. It has a stellar classification of B1IVe, which means it is a subgiant star of class B that displays emission lines in its spectrum. This is a variable star of the Gamma Cassiopeiae type, indicating it is a shell star with a circumstellar disk of gas about the equator, and has the variable star designation BZ Crucis. It is not known to be a member of a binary system, although it is probably a member of the open cluster NGC 4609. This star is moderately luminous in the X-ray band, with a variable energy emission of 1032–33 erg s−1 in the range 0.2−12 keV. The X-ray emission may be caused by magnetic activity, or possibly by accretion onto a white dwarf companion.
HD 91496 is a giant star in the constellation Carina, with an apparent magnitude is 4.92 and an MK spectral class of K4/5 III. It has been suspected of varying in brightness, but this has not been confirmed.
106 Herculis is a variable star in the northern constellation Hercules. It is visible to the naked eye as a faint, red-hued point of light with a baseline apparent visual magnitude of 4.96. Based on its parallax, it is estimated to lie 383 light-years away from the Sun. The star is moving closer to the Earth with a heliocentric radial velocity of -35 km/s.
1 Persei is an eclipsing binary star in the constellation Perseus. Its uneclipsed apparent magnitude is 5.49. The binary star consists of two B2 type main-sequence stars in a 25.9 day eccentric orbit. The stars are surrounded by a faint cloud of gas visible in mid-infrared, although whether they are the origin of the gas or simply passing through it is unclear.
HY Velorum is a binary star system in the southern constellation of Vela. It is a dim star but visible to the naked eye with an apparent visual magnitude of 4.83. The distance to this system, as estimated from its annual parallax shift of 7.1 mas, is 460 light years. HY Vel most likely forms a gravitationally bound pair with the magnitude 5.45 binary system KT Vel ; both are members of the IC 2391 open cluster. As of 1998, HY Vel and KT Vel had an angular separation of 76.1″ along a position angle of 311°.
HD 65750, also known as V341 Carinae is a bright red giant star in the constellation Carina. It is surrounded by a prominent reflection nebula, known as IC 2220, nicknamed the Toby Jug Nebula.
SX Centauri is a variable star in the constellation Centaurus. An RV Tauri variable, its light curve alternates between deep and shallow minima, varying its apparent magnitude from 9.1 to 12.4. From the period-luminosity relationship, it is estimated to be around 1.6 kpc from Earth. Gaia Data Release 2 gives a parallax of 0.2175 mas, corresponding to distance of about 4,600 pc.
V957 Scorpii is a variable star in the constellation of Scorpius. It is a blue straggler in the open cluster Messier 7, a star that is unexpectedly hot compared to other members of the cluster.
Collinder 228 is an open cluster within the southern part of the Carina Nebula NGC 3372, about 25' south of η Carinae. It is probably composed of stars which recently formed from the material in the nebula. QZ Carinae is the brightest member of Collinder 228 with an apparent magnitude between 6.16 and 6.49.
HD 150193 is a binary star system in the constellation of Ophiuchus. The primary star was identified as a Herbig Ae/Be star with a strong solar wind, losing approximately a tenth of solar mass per million years. It does host a very small debris disk, likely due to disk truncation by the nearby stellar companion. The disk is inclined 38±9° to the plane of sky. It appears to be highly evolved and asymmetric, with indications of flattening and grains growth.