Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Gemini |
Right ascension | 06h 09m 43.9853s [1] |
Declination | +23° 06′ 48.472″ [1] |
Apparent magnitude (V) | 5.71 - 5.77 [2] |
Characteristics | |
Spectral type | B3Ia [3] |
U−B color index | −0.63 [4] |
B−V color index | +0.21 [4] |
Variable type | α Cyg [5] [2] |
Astrometry | |
Radial velocity (Rv) | 16.00±4.3 [6] km/s |
Proper motion (μ) | RA: −0.064 [1] mas/yr Dec.: −2.685 [1] mas/yr |
Parallax (π) | 0.3878 ± 0.0616 mas [1] |
Distance | approx. 8,000 ly (approx. 2,600 pc) |
Absolute magnitude (MV) | −6.26 [7] |
Details | |
Mass | 21 [7] M☉ |
Radius | 55 [8] R☉ |
Luminosity | 204,000 [8] L☉ |
Surface gravity (log g) | 2.45 [8] cgs |
Temperature | 16,500 [8] K |
Rotational velocity (v sin i) | 80 [8] km/s |
Other designations | |
Database references | |
SIMBAD | data |
3 Geminorum is a blue supergiant star in the constellation Gemini. It is a small amplitude pulsating variable and a close double star, with a mean combined apparent visual magnitude of about 5.7.
3 Geminorum was found to be an α Cygni variable in 1998 and given the designation PU Geminorum. It varies by a few tenths of a magnitude [5] with a main period of 6.807 days [2] and a secondary period of 25 days. [8]
3 Geminorum is also a close double star. The brighter component is the variable blue supergiant. The companion is 2.5 magnitudes fainter. The separation is about 0.6 arc-seconds. [10] There is also a much fainter, approximately 14th magnitude, star 14" away. [11]
Faint Hα emission lines have been detected in the spectrum of 3 Geminorum, [12] but this is not usually expressed in published spectral classifications. [3] An "e" is only occasionally appended to the spectral type to reflect the emission lines. [13] [5] 3 Geminorum has frequently been classified as a normal supergiant (luminosity class Ib), [14] although a bright supergiant (Ia) luminosity class is now preferred. [3]
3 Geminorum can be occulted by the Moon. Observations of these occultations can give information about the angular diameter of a star, or about close companions. Occultations of 3 Geminorum have been observed, but no double or diameter information has been published. [15]
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.
119 Tauri is a red supergiant star in the constellation Taurus. It is a semiregular variable and its angular diameter has been measured at about 10 mas.
1 Vulpeculae is a class B4IV star in the constellation Vulpecula. Its apparent magnitude is 4.77 and it is approximately 780 light years away based on parallax.
32 Cygni is the Flamsteed designation for a binary star system in the Cygnus constellation. It is a 4th magnitude star, which can be seen with the naked eye under suitably dark skies. Parallax measurements give an estimated distance of 1,100 light-years (320 parsecs) from the Earth. However, Schröder et al. (2007) suggest the actual value, after correcting for Malmquist bias, may be closer to 1,174 light-years (360 parsecs). Although it is a spectrsocopic binary with components that cannot be separated visually, it has two entries in the Henry Draper Catalogue, with identical magnitudes and positions, but showing the spectral types of the two components.
NO Aurigae is a pulsating variable star in the constellation Auriga. It is an unusually-luminous asymptotic giant branch star about 3,500 light years away.
6 Cassiopeiae is a white hypergiant in the constellation Cassiopeia, and a small-amplitude variable star.
V381 Cephei is a triple star system in the northern constellation of Cepheus. Its apparent magnitude is slightly variable between 5.5 and 5.7.
Pi Leonis, Latinised from π Leonis, is a single star in the zodiac constellation Leo. It is a red-hued star that is visible to the naked eye with an apparent visual magnitude of 4.70. This object is located at a distance of some 410 light-years from the Sun based on parallax, and is drifting further away with a radial velocity of +22 km/s. Because the star lies near the ecliptic it is subject to occultations by the Moon.
Sigma Ophiuchi, Latinized from σ Ophiuchi, is a single, orange-hued star in the equatorial constellation Ophiuchus. Its apparent visual magnitude is 4.31, which is bright enough to be faintly visible to the naked eye. The annual parallax shift of 3.62 mas as seen from Earth provides a distance estimate of roughly 900 light years. It is moving closer to the Sun with a radial velocity of −28 km/s.
1 Puppis is a single star in the southern constellation of Puppis. It lies in the northern part of the constellation at a distance of about 790 ly, east of Aludra in Canis Major and just north of the white supergiant, 3 Puppis. This object is visible to the naked eye as a faint, red-hued star with an apparent visual magnitude of 4.59. It is moving further from the Earth with a heliocentric radial velocity of +32.4 km/s.
V1073 Scorpii is a variable star in the constellation Scorpius. It has a non-Greek Bayer designation of k Scorpii. The star has a blue-white hue and is visible to the naked eye with an apparent visual magnitude that fluctuates around +4.87. Parallax measurements yield a distance estimate of approximately 2,920 ly (896 pc) from the Sun, and it is drifting further away with a radial velocity of +7 km/s. It has an absolute magnitude of −6.8
Y Centauri or Y Cen is a semiregular variable star in the constellation of Centaurus.
10 Persei is a blue supergiant star in the constellation Perseus. Its apparent magnitude is 6.26 although it is slightly variable.
Y Lyncis is a semiregular variable star in the constellation Lynx. It is an asymptotic giant branch star of spectral type M6S, with a luminosity class of Ib, indicating a supergiant luminosity. It is around 1,160 light years away.
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.
V915 Scorpii is an orange hypergiant variable star in the constellation Scorpius.
TV Geminorum is a variable red supergiant in the constellation Gemini. Its visual magnitude varies from 6.3 to 7.5.
DS Crucis is a variable star near the open cluster NGC 4755, which is also known as the Kappa Crucis Cluster or Jewel Box Cluster. It is in the constellation Crux.
DU Crucis is a red supergiant and slow irregular variable star in the open cluster NGC 4755, which is also known as the Kappa (κ) Crucis Cluster or Jewel Box Cluster.
6 Geminorum is a variable star in the zodiac constellation of Gemini, located roughly 5,800 light years away from the Sun. It has the variable star designation BU Geminorum; 6 Geminorum is the Flamsteed designation. At its brightest this reddish hued star is barely visible to the naked eye but is readily visible with binoculars, found southeast of M 35, just to the south of WY Geminorum. It is moving further from the Earth with a heliocentric radial velocity of +27 km/s. The star is a member of the Gemini OB1 association.