R Fornacis is a carbon star, a star on the
asymptotic giant branch with an excess of carbon over oxygen in its atmosphere due to fusion products being
dredged up to the surface from deep inside the star. It is also a Mira variable, a type of pulsating
giant star which varies by several
apparent magnitudes with a period of a few hundred days. R Fornacis has a period of 389 days and varies between extremes of magnitude 7.5 and 13.0, although average maximum and minimum magnitudes are 8.9 and 12.2 respectively..[9]
R Fornacis was discovered to be variable in 1896 after it had been observed with a different brightness to that shown in the
Cordoba Durchmusterung.[10] In 1983, an unusually deep minimum was observed, and later correlated with an asymmetric shell of material ejected from the surface of the star.[4] Unconfirmed visual estimates of the unusual minimum give a magnitude of 14.0, while infrared observations confirm the unusual variation.[9]
^
abSamus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1: B/gcvs.
Bibcode:
2009yCat....102025S.
^Yamashita, Y. (1975). "The C-classification of spectra of carbon stars. II". Tokyo. 15: 47.
Bibcode:
1975AnTok..15...47Y.
^
abDucati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237.
Bibcode:
2002yCat.2237....0D.
^
abcAnders, F.; Khalatyan, A.; Chiappini, C.; Queiroz, A. B.; Santiago, B. X.; Jordi, C.; Girardi, L.; Brown, A. G. A.; Matijevič, G.; Monari, G.; Cantat-Gaudin, T.; Weiler, M.; Khan, S.; Miglio, A.; Carrillo, I.; Romero-Gómez, M.; Minchev, I.; De Jong, R. S.; Antoja, T.; Ramos, P.; Steinmetz, M.; Enke, H. (2019). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy and Astrophysics. 628: A94.
arXiv:1904.11302.
Bibcode:
2019A&A...628A..94A.
doi:
10.1051/0004-6361/201935765.
S2CID131780028.
^Pickering, E. C.; Leland, E. F. (1896). "Harvard College Observatory, circular no. 10. Six new variable stars". The Astrophysical Journal. 4: 234.
Bibcode:
1896ApJ.....4..234P.
doi:
10.1086/140271.