RS Persei


RS Persei is a red supergiant variable star located in the Double Cluster in Perseus. The star's apparent magnitude varies from 7.82 to 10.0, meaning it is never visible to the naked eye.

RS Persei
The Double Cluster.jpg
RS Persei is the red star closest to the centre of NGC 884, the right hand cluster (north is down).
Observation data
Epoch J2000      Equinox J2000
Constellation Perseus
Right ascension 2h 22m 24.288s[1]
Declination +57° 06′ 34.08″[1]
Apparent magnitude (V) 7.82-10.0[2]
Spectral type M4Iab[3]
Variable type SRc[2]
Radial velocity (Rv)−38.0±2[4] km/s
Proper motion (μ) RA: −0.371±0.137[5] mas/yr
Dec.: −0.931±0.165[5] mas/yr
Parallax (π)0.6437 ± 0.0822 mas[5]
Distanceapprox. 5,100 ly
(approx. 1,600 pc)
Absolute magnitude (MV)−6.18[6]
Mass12-15[7] M
Radius491[8] - 547[9] R
Luminosity33,000 - 34,000[8] L
Surface gravity (log g)−0.2±0.05 cgs
Temperature3,535±170[8] K
Other designations
RS Per, HD 14488, BD+56°583, 2MASS J02222428+5706340, AAVSO 0215+56A
Database references


RS Persei is a member of the cluster NGC 884, χ Persei, one half of the famous Double Cluster.[10]


RS Persei is classified as a semiregular variable star, with its brightness varying from magnitude 7.82 to 10.0 over 245 days,[2] Detailed studies show that it also pulsates with a long secondary period of 4,200±1,500 days.[11]


RS Persei is a large cool star with a temperature of 3,500 K. This makes it luminous, although much of its radiation is emitted in the infrared. In 2005, RS Per was calculated to have a bolometric luminosity of 145,000 L and a radius around 1,000 R.[6] More recently, 2014 calculations across all wavelengths gives the star a lower luminosity of 77,600+9,500
based on an assumed distance, and a radius of 770±30 R based on the measured angular diameter and luminosity.[7]

Even more recent measurements based on its Gaia Data Release 2 parallax gives a luminosity below 40,000 L with a corresponding radius of 491 R.[8] It is surrounded by dust that has condensed from material lost by the star.[12]

RS Persei has sometimes been considered to be a highly evolved low mass Asymptotic Giant Branch (AGB) star,[13] but calculations of its current mass suggest that it is a low mass supergiant. NGC 244 is also too young to host AGB stars.[7]


  1. ^ a b Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
  2. ^ a b c Samus', N. N.; Goranskii, V. P.; Durlevich, O. V.; Zharova, A. V.; Kazarovets, E. V.; Kireeva, N. N.; Pastukhova, E. N.; Williams, D. B.; Hazen, M. L. (2003). "An Electronic Version of the Second Volume of the General Catalogue of Variable Stars with Improved Coordinates". Astronomy Letters. 29 (7): 468. Bibcode:2003AstL...29..468S. doi:10.1134/1.1589864. S2CID 16299532.
  3. ^ Saesen, S.; Carrier, F.; Pigulski, A.; Aerts, C.; Handler, G.; Narwid, A.; Fu, J. N.; Zhang, C.; Jiang, X. J.; Vanautgaerden, J.; Kopacki, G.; Stęślicki, M.; Acke, B.; Poretti, E.; Uytterhoeven, K.; Gielen, C.; Østensen, R.; De Meester, W.; Reed, M. D.; Kołaczkowski, Z.; Michalska, G.; Schmidt, E.; Yakut, K.; Leitner, A.; Kalomeni, B.; Cherix, M.; Spano, M.; Prins, S.; Van Helshoecht, V.; Zima, W.; Huygen, R.; Vandenbussche, B.; Lenz, P.; Ladjal, D.; Puga Antolín, E.; Verhoelst, T.; De Ridder, J.; Niarchos, P.; Liakos, A.; Lorenz, D.; Dehaes, S.; Reyniers, M.; Davignon, G.; Kim, S.-L.; Kim, D. H.; Lee, Y.-J.; Lee, C.-U.; Kwon, J.-H.; Broeders, E.; Van Winckel, H.; Vanhollebeke, E.; Waelkens, C.; Raskin, G.; Blom, Y.; Eggen, J. R.; Degroote, P.; Beck, P.; Puschnig, J.; Schmitzberger, L.; Gelven, G. A.; Steininger, B.; Blommaert, J.; Drummond, R.; Briquet, M.; Debosscher, J. (2010). "Photometric multi-site campaign on the open cluster NGC 884". Astronomy and Astrophysics. 515: A16. arXiv:1001.1116. Bibcode:2010A&A...515A..16S. doi:10.1051/0004-6361/200913236. ISSN 0004-6361. S2CID 40932414.
  4. ^ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington. Bibcode:1953GCRV..C......0W.
  5. ^ a b c 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.
  6. ^ a b Levesque, Emily M.; Massey, Philip; Olsen, K. A. G.; Plez, Bertrand; Josselin, Eric; Maeder, Andre; Meynet, Georges (2005). "The Effective Temperature Scale of Galactic Red Supergiants: Cool, but Not As Cool As We Thought". The Astrophysical Journal. 628 (2): 973–985. arXiv:astro-ph/0504337. Bibcode:2005ApJ...628..973L. doi:10.1086/430901. S2CID 15109583.
  7. ^ a b c Baron, F.; Monnier, J. D.; Kiss, L. L.; Neilson, H. R.; Zhao, M.; Anderson, M.; Aarnio, A.; Pedretti, E.; Thureau, N.; Ten Brummelaar, T. A.; Ridgway, S. T.; McAlister, H. A.; Sturmann, J.; Sturmann, L.; Turner, N. (2014). "CHARA/MIRC Observations of Two M Supergiants in Perseus OB1: Temperature, Bayesian Modeling, and Compressed Sensing Imaging". The Astrophysical Journal. 785 (1): 46. arXiv:1405.4032. Bibcode:2014ApJ...785...46B. doi:10.1088/0004-637X/785/1/46. S2CID 17085548.
  8. ^ a b c d Messineo, M.; Brown, A. G. A. (2019). "A Catalog of Known Galactic K-M Stars of Class I Candidate Red Supergiants in Gaia DR2". The Astronomical Journal. 158 (1): 20. arXiv:1905.03744. Bibcode:2019AJ....158...20M. doi:10.3847/1538-3881/ab1cbd. S2CID 148571616.
  9. ^ Norris, Ryan P. (2019). Seeing Stars Like Never Before: A Long-term Interferometric Imaging Survey of Red Supergiants (PDF) (PhD). Georgia State University.
  10. ^ Mermilliod, J. C.; Mayor, M.; Udry, S. (2008). "Red giants in open clusters. XIV. Mean radial velocities for 1309 stars and 166 open clusters". Astronomy and Astrophysics. 485 (1): 303–314. Bibcode:2008A&A...485..303M. doi:10.1051/0004-6361:200809664.
  11. ^ Kiss, L. L.; Szabó, Gy. M.; Bedding, T. R. (2006). "Variability in red supergiant stars: Pulsations, long secondary periods and convection noise". Monthly Notices of the Royal Astronomical Society. 372 (4): 1721–1734. arXiv:astro-ph/0608438. Bibcode:2006MNRAS.372.1721K. doi:10.1111/j.1365-2966.2006.10973.x. S2CID 5203133.
  12. ^ Verhoelst, T.; Van Der Zypen, N.; Hony, S.; Decin, L.; Cami, J.; Eriksson, K. (2009). "The dust condensation sequence in red supergiant stars". Astronomy and Astrophysics. 498 (1): 127–138. arXiv:0901.1262. Bibcode:2009A&A...498..127V. doi:10.1051/0004-6361/20079063. S2CID 18383796.
  13. ^ Yoon, Dong-Hwan; Cho, Se-Hyung; Kim, Jaeheon; Yun, Young joo; Park, Yong-Sun (2014). "SiO and H2O Maser Survey toward Post-asymptotic Giant Branch and Asymptotic Giant Branch Stars". The Astrophysical Journal Supplement. 211 (1): 15. Bibcode:2014ApJS..211...15Y. doi:10.1088/0067-0049/211/1/15.

External linksEdit

  • Light curve
  • VSX entry