R Cancri

Not to be confused with Rho Cancri.

R Cancri is a Mira variable in the constellation Cancer. Located approximately 250 parsecs (830 ly) distant, it varies between magnitudes 6.07 and 12.3 over a period of approximately 357 days.^[3] At its brightest, it is very faintly visible to the naked eye.

R Cancri

The visual band light curve of R Cancri, from AAVSO data[1]
Observation data Epoch J2000      Equinox J2000
Constellation	Cancer
Right ascension	08h 16m 33.82673s[2]
Declination	+11° 43′ 34.4691″[2]
Apparent magnitude (V)	6.07 - 12.3[3]
Characteristics
Spectral type	M6e-M9e[3]
U−B color index	0.49[4]
B−V color index	1.53[4]
Variable type	Mira[3]
Astrometry
Radial velocity (Rv)	35.42 ± 0.52[5] km/s
Proper motion (μ)	RA: 0.635±0.195[2] mas/yr Dec.: −10.785±0.106[2] mas/yr
Parallax (π)	3.9375 ± 0.1792 mas[2]
Distance	854+36 −39 ly (262+11 −12 pc)[6]
Details
Mass	1.67[7] M☉
Radius	371±37[8] R☉
Luminosity	5,700[8][a] L☉
Surface gravity (log g)	−0.608[7] cgs
Temperature	2,604±300[8] K
Metallicity [Fe/H]	+0.29[7] dex
Other designations
BD+12°1803, HD 69243, HIP 40534, HR 3248, SAO 97694
Database references
SIMBAD	data

Friedrich Magnus Schwerd discovered R Cancri in 1829.^[9] It was one of the first variable stars to be discovered.^[10]

Notes

1. Calculated using the given radius and temperature by the Stefan-Boltzmann law.

References

1. "Download Data". aavso.org. AAVSO. Retrieved 1 October 2021.
2. Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
3. VSX; Otero, S. A. (7 January 2011). "R Cancri". AAVSO Website. American Association of Variable Star Observers. Retrieved 26 Jan 2021.
4. Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237: 0. Bibcode:2002yCat.2237....0D.
5. Famaey, B.; Jorissen, A.; Luri, X.; Mayor, M.; Udry, S.; Dejonghe, H.; Turon, C. (2005). "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data". Astronomy and Astrophysics. 430 (165): 165–186. arXiv:astro-ph/0409579. Bibcode:2005A&A...430..165F. doi:10.1051/0004-6361:20041272. S2CID 17804304.
6. Bailer-Jones, C. A. L.; Rybizki, J.; Fouesneau, M.; Demleitner, M.; Andrae, R. (2021-03-01). "Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3". The Astronomical Journal. 161 (3): 147. arXiv:2012.05220. Bibcode:2021AJ....161..147B. doi:10.3847/1538-3881/abd806. ISSN 0004-6256. Data about this star can be seen here.
7. Anders, F.; Khalatyan, A.; Queiroz, A. B. A.; Chiappini, C.; Ardèvol, J.; Casamiquela, L.; Figueras, F.; Jiménez-Arranz, Ó.; Jordi, C.; Monguió, M.; Romero-Gómez, M.; Altamirano, D.; Antoja, T.; Assaad, R.; Cantat-Gaudin, T. (2022-02-01). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia EDR3 stars brighter than G = 18.5". Astronomy and Astrophysics. 658: A91. arXiv:2111.01860. Bibcode:2022A&A...658A..91A. doi:10.1051/0004-6361/202142369. ISSN 0004-6361. Database at VizieR.
8. Karovicova, I.; Wittkowski, M.; Ohnaka, K.; Boboltz, D. A.; Fossat, E.; Scholz, M. (2013-12-01). "New insights into the dust formation of oxygen-rich AGB stars". Astronomy & Astrophysics. 560: A75. arXiv:1310.1924. Bibcode:2013A&A...560A..75K. doi:10.1051/0004-6361/201322376. ISSN 0004-6361.
9. Cannon, Annie J. (1907). "Second catalogue of variable stars". Annals of Harvard College Observatory. 55: 1–94. Bibcode:1907AnHar..55....1C. Retrieved 20 December 2024.
10. "The First Known Variable Stars". Students for the Exploration and Development of Space. Retrieved 1 January 2025.