40 Cancri - Misplaced Pages

Star in the constellation Cancer

40 Cancri
Observation data Epoch J2000.0 Equinox J2000.0
Constellation	Cancer
Right ascension	08 40 11.45280
Declination	+19° 58′ 16.0852″
Apparent magnitude (V)	6.61
Characteristics
Evolutionary stage	main sequence
Spectral type	A1 V
B−V color index	0.006±0.005
Astrometry

Radial velocity (R_v)	+34.4±0.6 km/s
Proper motion (μ)	RA: −35.312 mas/yr Dec.: −13.595 mas/yr
Parallax (π)	5.2065 ± 0.0713 mas
Distance	626 ± 9 ly (192 ± 3 pc)
Absolute magnitude (M_V)	0.32

Details

Mass	2.46±0.12 `M`_☉
Radius	2.72±0.12 `R`_☉
Luminosity	73.68 `L`_☉
Surface gravity (log g)	3.78 cgs
Temperature	9,382 K
Rotational velocity (v sin i)	10 km/s

Other designations
40 Cnc, BD+20°2159, HD 73666, HIP 42523, SAO 80336, WDS J08401+2000
Database references
SIMBAD	data

40 Cancri is a binary star system in the zodiac constellation of Cancer, located about 614 light years from the Sun in the Beehive Cluster (NGC 2632). It is a challenge to view with the naked eye, having an apparent visual magnitude of 6.61. The system is moving further from the Earth with a heliocentric radial velocity of 34 km/s.

The primary component appears to be a normal A-type main-sequence star with a stellar classification of A1 V, showing neither an organized magnetic field nor a chemical peculiarity. However, it has an excessive temperature for its luminosity, and thus is considered an extreme blue straggler. 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.

With an effective temperature of 9,382 K, this is the hottest star in the cluster 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, with a projected rotational velocity of 10 km/s. It is radiating 74 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.

References

^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
^ Bidelman, William P. (August 1956), "Spectral Classification of the Brighter Stars of the Praesepe Cluster", Publications of the Astronomical Society of the Pacific, 68 (403): 318, Bibcode:1956PASP...68..318B, doi:10.1086/126944.
^ Fossati, L.; et al. (January 2010), "Explaining the Praesepe blue straggler HD 73666", Astronomy and Astrophysics, 510: A8, arXiv:0911.1874, Bibcode:2010A&A...510A...8F, doi:10.1051/0004-6361/200811495, S2CID 118658470, A8.
^ Fossati, L.; et al. (December 2007), "Late stages of the evolution of A-type stars on the main sequence: comparison between observed chemical abundances and diffusion models for 8 Am stars of the Praesepe cluster", Astronomy and Astrophysics, 476 (2): 911–925, arXiv:0710.0579, Bibcode:2007A&A...476..911F, doi:10.1051/0004-6361:20078320, S2CID 16152096.
"40 Cnc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-03-03.
^ Andrievsky, Sergei. M. (June 1998), "Blue stragglers in open clusters. I. NGC 2632", Astronomy and Astrophysics, 334: 139−145, Bibcode:1998A&A...334..139A.

Constellation of Cancer

Stars

Bayer	α (Acubens) β (Tarf) γ (Asellus Borealis) δ (Asellus Australis) ε (Meleph) ζ (Tegmine) ζ η θ ι κ λ (Piautos) μ μ ν ξ (Nahn) ο ο π π ρ (Copernicus) ρ σ σ σ τ υ υ φ φ χ ψ ψ ω ω
Flamsteed	1 3 5 7 8 11 12 15 20 (d) 21 24 25 (d) 27 28 (CX) 29 34 35 36 (c) 37 38 39 40 42 44 45 (A) 46 49 (b) 50 (A) 53 54 57 60 61 66 67 68 70 71 75 78 79 80 83
Variable	R X RS VZ AZ DX EI HL HM
HD	72945 72946 73534 (Gakyid) 79498
Other	GJ 3470 (Kaewkosin) HIP 41378 K2-187 LHS 2090 Pr0211 WD J0914+1914 YBP 1194

Exoplanets	55 Cancri b c d e f β Cancri b GJ 3470 b HD 73534 b HIP 41378 b c d e f Pr0201 b

Star clusters	Beehive Cluster Messier 67

Nebulae	Abell 30 Abell 31

Galaxies

NGC	2503 2535 2536 2608 2623 2648 2775 2801 2803 2804 2812
Other	3C 191 3C 212 3C 215 DLA0817g IC 2431 OJ 287 QSO B0839+187 UGC 4457 4C +29.30 SDSS J0849+1114

Galaxy clusters	Abell 671 Musket Ball Cluster