Variable star in the constellation Octans
R Octantis , also known as HD 40857 , is a solitary, red hued variable star located in the southern circumpolar constellation Octans . It has an apparent magnitude that varies in-between 6.4 and 13.2 within 405 days .[ 3] naked eye . The object is located relatively far at a distance of about 1,900 light years based on parallax measurements from Gaia DR3 ,[ 2] radial velocity of km/s [ 6]
R Octantis has been known to have a peculiar spectra since 1892.[ 10] [ 11] [ 12] Mira variable .[ 4] oxygen on its outer layers.[ 13]
The object has an average stellar classification of M5.5e, indicating that it is a M-type star with emission lines in its spectrum.[ 4] [ 3] asymptotic giant branch , generating energy by fusing hydrogen and helium shells around an inert carbon core. As a result, it has expanded to 466 times the radius of the Sun .[ 7] luminosity of the Sun from its photosphere at an effective temperature of K [ 8]
^ "Download Data" . aavso.org . AAVSO. Retrieved 1 October 2021 .^ a b c d e 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 .^ a b c d Otero, Sebastian (26 April 2011). "R Octantis" . AAVSO Website . American Association of Variable Star Observers . Retrieved 21 April 2016 . ^ a b c Keenan, Philip C. (June 1966). "A Catalogue of Spectra of Mira Variables of Types ME and Se" . The Astrophysical Journal Supplement Series . 13 : 333. Bibcode :1966ApJS...13..333K . doi :10.1086/190139 eISSN 1538-4365 . ISSN 0067-0049 . ^ Samus’, N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (January 2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports . 61 (1): 80– 88. Bibcode :2017ARep...61...80S . doi :10.1134/S1063772917010085 . eISSN 1562-6881 . ISSN 1063-7729 . S2CID 125853869 . ^ a b Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters . 32 (11): 759– 771. arXiv :1606.08053 Bibcode :2006AstL...32..759G . doi :10.1134/S1063773706110065 . eISSN 1562-6873 . ISSN 1063-7737 . S2CID 119231169 . ^ a b c Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric (2022). "Stellar and substellar companions from Gaia EDR3" . Astronomy & Astrophysics . 657 : A7. arXiv :2109.10912 Bibcode :2022A&A...657A...7K . doi :10.1051/0004-6361/202142146 eISSN 1432-0746 . ISSN 0004-6361 . ^ a b c McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (2012). "Fundamental Parameters and Infrared Excesses of Hipparcos Stars" . Monthly Notices of the Royal Astronomical Society . 427 (1): 343– 57. arXiv :1208.2037 Bibcode :2012MNRAS.427..343M . doi :10.1111/j.1365-2966.2012.21873.x S2CID 118665352 . ^ "V* R Oct" . SIMBAD Centre de données astronomiques de Strasbourg . Retrieved 21 April 2016 .^ Fleming, M. (November 1892). "Stars having peculiar spectra". Astronomy and Astro-Physics . 11 : 765– 767. Bibcode :1892AstAp..11..765F . ^ Bidelman, William P. (November 1954). "Catalogue and Bibliography of Emission-Line Stars of Types Later than B.". The Astrophysical Journal Supplement Series . 1 : 175. Bibcode :1954ApJS....1..175B . doi :10.1086/190007 . eISSN 1538-4365 . ISSN 0067-0049 . ^ Campbell, Leon (1955). Studies of Long Period Variables . American Association of Variable Star Observers. Bibcode :1955slpv.book.....C . ^ Jura, M.; Yamamoto, A.; Kleinmann, S. G. (August 1993). "Long-period oxygen-rich optical Miras in the solar neighborhood". The Astrophysical Journal . 413 : 298. Bibcode :1993ApJ...413..298J . doi :10.1086/172997 . eISSN 1538-4357 . ISSN 0004-637X .
