R Volantis
Mira variable carbon star in Volans with emission lines.
R Volantis is a solitary variable star located in the southern circumpolar constellation Volans. Its brightness ranges from an apparent magnitude of about 8.7 at its brightest, easily visible through amateur telescopes but not to the unaided eye, down to roughly magnitude 13.9 at its dimmest. The star lies approximately 2,300 light-years away and is moving closer to Earth, with a radial velocity of −5 km/s.
First spotted at Cape Observatory in 1899, R Volantis drew attention in 1954 when emission lines were detected in its spectrum. Observations between 1955 and 1967 indicated it was likely a Mira variable, leading to its current designation. Its classification as a carbon star came later, in 1968, when Pik-Sin The studied its spectrum alongside that of V1163 Centauri (HD 114586); the former was identified as a carbon star, the latter as an S-type star.
The star holds a stellar classification of Ce, marking it as a carbon star with emission lines. It is a giant on the asymptotic giant branch, generating energy through hydrogen and helium shells surrounding an inert carbon core. Consequently, it has expanded to 360 times the Sun’s radius and shines with a luminosity of 11,438 times that of the Sun, at an effective temperature of roughly 3,100 K, which gives it a red color. Its brightness varies with a period of 445 days.
- Constellation
- Volans
- Apparent magnitude range
- 8.7 to 13.9
- Period
- 445 days
- Spectral type
- Ce
- Distance
- about 2,300 light years
- Radial velocity
- −5 km/s
- Radius
- 360 R☉
- Luminosity
- 11,438 L☉
- Effective temperature
- 3,100 K
Lore & Background
R Volantis was discovered at Cape Observatory in 1899. Its peculiarity was first observed in 1954 when emission lines were found in its spectrum. Observations from 1955 to 1967 revealed it was a probable Mira variable, leading to its current designation. Its nature as a carbon star was not discovered until 1968 by Pik-Sin The, who studied its spectrum alongside that of V1163 Centauri (HD 114586), classifying R Volantis as a carbon star and the latter as an S-type star.
The star has a stellar classification of Ce, indicating a carbon star with emission lines. It is a giant star on the asymptotic giant branch, generating energy via hydrogen and helium shells around an inert carbon core. It has expanded to 360 times the Sun's radius, radiating a luminosity of 11,438 L☉ with an effective temperature of about 3,100 K, giving it a red hue.
R Volantis fluctuates between magnitude 8.7 and 13.9 with a period of 445 days. It is relatively far at a distance of about 2,300 light years but is drifting closer with a radial velocity of −5 km/s.
Reader's Guide
R Volantis is significant as a Mira variable and carbon star, a combination that makes it a valuable object for studying stellar evolution on the asymptotic giant branch. Its discovery history—first noted in 1899, with emission lines found in 1954, classified as a Mira variable by 1967, and identified as a carbon star in 1968 by Pik-Sin The—illustrates the gradual unveiling of its nature. The star's spectral class Ce (carbon star with emission lines) and its status as an asymptotic giant branch star highlight its advanced evolutionary stage, with an inert carbon core and energy from hydrogen and helium shell burning. Its large radius (360 R☉) and high luminosity (11,438 L☉) at a low effective temperature (3,100 K) produce its red hue. The 445-day period and magnitude range (8.7 to 13.9) make it a target for amateur astronomers, though it is not visible to the naked eye. Its radial velocity of −5 km/s indicates it is moving closer to Earth, though it remains about 2,300 light years away.
Did You Know?
- Its nature as a carbon star was discovered in 1968 by Pik-Sin The.
- It has a period of 445 days and varies between magnitude 8.7 and 13.9.
- The star is an asymptotic giant branch star with an inert carbon core.
More in Variable Stars 1-24
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