Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Cancer |
Right ascension | 08h 40m 11.45280s [1] |
Declination | +19° 58′ 16.0852″ [1] |
Apparent magnitude (V) | 6.61 [2] |
Characteristics | |
Evolutionary stage | main sequence |
Spectral type | A1 V [3] |
B−V color index | 0.006±0.005 [2] |
Astrometry | |
Radial velocity (Rv) | +34.4±0.6 [2] km/s |
Proper motion (μ) |
RA: −35.312
[1]
mas/
yr Dec.: −13.595 [1] mas/ yr |
Parallax (π) | 5.2065 ± 0.0713 mas [1] |
Distance | 626 ± 9
ly (192 ± 3 pc) |
Absolute magnitude (MV) | 0.32 [2] |
Details | |
Mass | 2.46±0.12 [4] M☉ |
Radius | 2.72±0.12 [4] R☉ |
Luminosity | 73.68 [2] L☉ |
Surface gravity (log g) | 3.78 [5] cgs |
Temperature | 9,382 [5] K |
Rotational velocity (v sin i) | 10 [5] km/s |
Other designations | |
Database references | |
SIMBAD | data |
40 Cancri is a binary star [4] system in the zodiac constellation of Cancer, located about 614 [1] light years from the Sun in the Beehive Cluster ( NGC 2632). [4] It is a challenge to view with the naked eye, having an apparent visual magnitude of 6.61. [2] The system is moving further from the Earth with a heliocentric radial velocity of 34 km/s. [2]
The primary component appears to be a normal A-type main-sequence star with a stellar classification of A1 V, [3] showing neither an organized magnetic field nor a chemical peculiarity. [5] However, it has an excessive temperature for its luminosity, and thus is considered an extreme [4] blue straggler. [7] This is a second generation star formed through a collision of two low mass stars some 5–350 million years ago. The collision was either between two separate cluster members or the coalescence of a binary star system. [4]
With an effective temperature of 9,382 [5] K, this is the hottest star in the cluster [7] by about 1,200 K. It has 2.46 times the mass of the Sun and 2.72 times the Sun's radius. The star has an unusually slow rotation for an A1V star, [4] with a projected rotational velocity of 10 km/s. [5] It is radiating 74 [2] times the Sun's luminosity from its photosphere.
40 Cancri has a common proper motion companion, located at an angular separation of 0.425 ″±0.009 ″ along a position angle of 127.6°±0.5°, as of 1983. This object is about 2.5±0.5 magnitudes dimmer than the primary, and is most likely an F-type star with a mass of about 1.5 M☉. The projected separation between the pair is 80 AU, so their orbital period is 450 years or greater. [4]