40 Cancri
| Observation data Epoch J2000.0 Equinox ICRS | |
|---|---|
| Constellation | Cancer |
| Right ascension | 08h 40m 11.45263s[1] |
| Declination | +19° 58′ 16.0832″[1] |
| Apparent magnitude (V) | 6.61[2] |
| Characteristics | |
| Evolutionary stage | blue straggler[3] |
| Spectral type | A1 V[4] |
| B−V color index | 0.006±0.005[2] |
| Astrometry | |
| Radial velocity (Rv) | +34.4±0.6[2] km/s |
| Proper motion (μ) | RA: −35.154[1] mas/yr Dec.: −13.463[1] mas/yr |
| Parallax (π) | 5.3784±0.0417 mas[1] |
| Distance | 606 ± 5 ly (186 ± 1 pc) |
| Absolute magnitude (MV) | 0.32[2] |
| Details | |
| Mass | 2.46±0.12[5] M☉ |
| Radius | 2.72±0.12[5] R☉ |
| Luminosity | 91[1] L☉ |
| Surface gravity (log g) | 3.78[6] cgs |
| Temperature | 9,382[6] K |
| Rotational velocity (v sin i) | 10[6] km/s |
| Age | 349[1] Myr |
| Other designations | |
| 40 Cnc, BD+20°2159, HD 73666, HIP 42523, SAO 80336, WDS J08401+2000[7] | |
| Database references | |
| SIMBAD | data |
40 Cancri is a binary star[5] system in the zodiac constellation of Cancer, located about 605 light years from the Sun in the Beehive Cluster (NGC 2632).[5] 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,[4] showing neither an organized magnetic field nor a chemical peculiarity.[6] However, it is considered an extreme[5] blue straggler.[3] 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.[5]
With an effective temperature of 9,382 K,[6] this is the hottest star in the cluster[3] 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,[5] with a projected rotational velocity of 10 km/s.[6] It is radiating 91 times the Sun's luminosity from its photosphere.[1]
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.[5]
References
[edit]- 1 2 3 4 5 6 7 8 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- 1 2 3 4 5 6 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.
- 1 2 3 Andrievsky, Sergei. M. (June 1998), "Blue stragglers in open clusters. I. NGC 2632", Astronomy and Astrophysics, 334: 139−145, Bibcode:1998A&A...334..139A.
- 1 2 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.
- 1 2 3 4 5 6 7 8 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.
- 1 2 3 4 5 6 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.
