R Volantis

R Volantis is a single variable star in the southern circumpolar constellation Volans. It has an apparent magnitude of around 8.7 at its maxima, making it readily visible in amateur telescopes but not to the naked eye. At its minimum brightness, it may be as faint as magnitude 13.9. The object is relatively far at a distance of about 2,300 light years but is drifting closer with a radial velocity of −5 km/s. R Volantis was discovered at Cape Observatory in 1899. The star's peculiarity was first observed in 1954 when it was found to have emission lines in its spectrum. Observations from 1955 to 1967 revealed that the star was a probable Mira variable and was given its current designation. However, its nature as a carbon star wasn't discovered until 1968 by Pik-Sin The. In their paper, R Volantis and V1163 Centauri (HD 114586) had their spectra studied and the former is classified as a carbon star while the latter is an S-type star. R Volantis has a stellar classification of Ce, indicating that it is a carbon star with emission lines. It is a giant star on the asymptotic giant branch, meaning that it is generating energy via hydrogen and helium shells around an inert carbon core. As a result, it has expanded to 360 times the radius of the Sun and now radiates a luminosity of 11,438 L☉, with an effective temperature of around 3,100 K, giving it a red hue. R Volantis fluctuates between magnitude 8.7 and 13.9, and has a period of 445 days.

Carbon star in the constellation Volans

R Volantis

A visual band light curve for R Volantis, plotted from AAVSO data[1]
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Volans
Right ascension	07h 05m 36.2081s[2]
Declination	−73° 00′ 52.034″[2]
Apparent magnitude (V)	8.78 - 11.50[3]
Characteristics
Evolutionary stage	AGB[4]
Spectral type	Ce[5]
Variable type	Mira[6]
Astrometry
Radial velocity (Rv)	−4.7[7] km/s
Proper motion (μ)	RA: −14.298 mas/yr[2] Dec.: +19.462 mas/yr[2]
Parallax (π)	1.3931±0.0631 mas[2]
Distance	2,317+97 −96 ly (710.7+29.9 −29.5 pc)[8]
Details
Mass	0.75[9] M☉
Radius	360[9][a] R☉
Luminosity	11,438[9] L☉
Temperature	3,140[9] K
Other designations
R Vol, CD−72°378, 2MASS J07053619-7300519
Database references
SIMBAD	data

R Volantis is a single variable star in the southern circumpolar constellation Volans. It has an apparent magnitude of around 8.7 at its maxima, making it readily visible in amateur telescopes but not to the naked eye. At its minimum brightness, it may be as faint as magnitude 13.9. The object is relatively far at a distance of about 2,300 light years but is drifting closer with a radial velocity of −5 km/s.

R Volantis was discovered at Cape Observatory in 1899.^[10] The star's peculiarity was first observed in 1954 when it was found to have emission lines in its spectrum.^[11] Observations from 1955 to 1967 revealed that the star was a probable Mira variable^[12] and was given its current designation. However, its nature as a carbon star wasn't discovered until 1968 by Pik-Sin The. In their paper, R Volantis and V1163 Centauri (HD 114586) had their spectra studied and the former is classified as a carbon star while the latter is an S-type star.^[13]

R Volantis has a stellar classification of Ce,^[5] indicating that it is a carbon star with emission lines. It is a giant star on the asymptotic giant branch,^[4] meaning that it is generating energy via hydrogen and helium shells around an inert carbon core. As a result, it has expanded to 360 times the radius of the Sun and now radiates a luminosity of 11,438 L_☉, with an effective temperature of around 3,100 K, giving it a red hue.^[9]

R Volantis fluctuates between magnitude 8.7 and 13.9,^[6] and has a period of 445 days.^[3]

Notes

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1. ^ Applying the Stefan–Boltzmann law with a nominal solar effective temperature of 5,772 K:

   ( 5 , 772 3 , 140 ) 4 ⋅ 11 , 438 = 360   R ⊙ {\displaystyle {\sqrt {{\biggl (}{\frac {5,772}{3,140}}{\biggr )}^{4}\cdot 11,438}}=360\ R_{\odot }} .

References

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1. ^ "Download Data". aavso.org. AAVSO. Retrieved 1 October 2021.
2. ^ ^{a b c d} 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. ^ ^{a b} Vogt, N.; Contreras-Quijada, A.; Fuentes-Morales, I.; Vogt-Geisse, S.; Arcos, C.; Abarca, C.; Agurto-Gangas, C.; Caviedes, M.; DaSilva, H.; Flores, J.; Gotta, V.; Peñaloza, F.; Rojas, K.; Villaseñor, J. I. (10 November 2016). "Determination of Pulsation Periods and Other Parameters of 2875 Stars Classified as MIRA in the All Sky Automated Survey (ASAS)". The Astrophysical Journal Supplement Series. 227 (1): 6. arXiv:1609.05246. Bibcode:2016ApJS..227....6V. doi:10.3847/0067-0049/227/1/6. eISSN 1538-4365.
4. ^ ^{a b} Montez, Rodolfo; Ramstedt, Sofia; Kastner, Joel H.; Vlemmings, Wouter; Sanchez, Enmanuel (22 May 2017). "A Catalog of GALEX Ultraviolet Emission from Asymptotic Giant Branch Stars". The Astrophysical Journal. 841 (1): 33. arXiv:1705.05371. Bibcode:2017ApJ...841...33M. doi:10.3847/1538-4357/aa704d. eISSN 1538-4357.
5. ^ ^{a b} Henize, K. G. (April 1976). "Observations of southern emission-line stars". The Astrophysical Journal Supplement Series. 30: 491. Bibcode:1976ApJS...30..491H. doi:10.1086/190369. eISSN 1538-4365. ISSN 0067-0049.
6. ^ ^{a b} 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. ISSN 1063-7729. S2CID 125853869.
7. ^ Menzies, John W.; Feast, Michael W.; Whitelock, Patricia A. (5 May 2006). "Carbon-rich Mira variables: radial velocities and distances". Monthly Notices of the Royal Astronomical Society. 369 (2): 783–790. arXiv:astro-ph/0603505. Bibcode:2006MNRAS.369..783M. doi:10.1111/j.1365-2966.2006.10323.x. ISSN 0035-8711.
8. ^ 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.
9. ^ ^{a b c d e} Rau, G.; Hron, J.; Paladini, C.; Aringer, B.; Eriksson, K.; Marigo, P.; Nowotny, W.; Grellmann, R. (2017-04-01). "The adventure of carbon stars. Observations and modeling of a set of C-rich AGB stars". Astronomy and Astrophysics. 600: A92. arXiv:1701.04331. Bibcode:2017A&A...600A..92R. doi:10.1051/0004-6361/201629337. ISSN 0004-6361.
10. ^ Cannon, Annie J. (1907). "Second catalogue of variable stars". Annals of Harvard College Observatory. 55: 1–94. Bibcode:1907AnHar..55....1C. Retrieved 16 August 2025.
11. ^ 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.
12. ^ Feuchter, A. Ch. (August 1967). "On several statistical characteristics of Mira variables". The Astronomical Journal. 72: 702. Bibcode:1967AJ.....72..702F. doi:10.1086/110295. ISSN 0004-6256.
13. ^ The, Pik-Sin (February 1968). "The Spectrum of the Variables R Vol and HD 114586". Publications of the Astronomical Society of the Pacific. 80 (472): 104. Bibcode:1968PASP...80..104T. doi:10.1086/128597. eISSN 1538-3873. ISSN 0004-6280.