R Sculptoris

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R Sculptoris
Location of R Sculptoris (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Sculptor
Right ascension 01h 26m 58.09462s[1]
Declination −32° 32′ 35.4377″[1]
Apparent magnitude (V) +5.72[2]
Characteristics
Spectral type C6,5ea(Np)[3]
U−B color index +7.67[2]
B−V color index +3.87[2]
Variable type SRb[4]
Astrometry
Radial velocity (Rv)−5.40[5] km/s
Proper motion (μ) RA: −9.784[1] mas/yr
Dec.: −30.900[1] mas/yr
Parallax (π)2.2724±0.1471 mas[1]
Distance1,180±140 ly
(361±44 pc)[6]
Absolute magnitude (MV)−0.45[7]
Details
Mass1.3±0.7 [8] M☉
Radius411±43[9] R☉
Luminosity8,000±1,000[9] L☉
Surface gravity (log g)−0.5±0.1[9] cgs
Temperature2640±80 [8] K
Metallicity [Fe/H]0.0[3] dex
Other designations
R Scl, CD−33°525, HD 8879, HIP 6759, HR 423, SAO 193122, WDS J01270-3233A, AAVSO 0122-33[10]
Database references
SIMBADdata

R Sculptoris is a variable star system in the southern constellation of Sculptor.[11][12] Parallax measurements provide a distance estimate of approximately 1,435 ± 98 light-years from the Sun.[1] An independent estimate based on measurements of an ejected shell surrounding the star yield a distance of 1,180 ± 140 light-years.[6] The star is drifting closer with a radial velocity of −5.4 km/s.[5]

Benjamin Apthorp Gould discovered that the star's brightness varies, in 1872. It was listed with its variable star designation, R Sculptoris, in Annie Jump Cannon's 1907 work Second Catalog of Variable Stars.[13] Although the General Catalogue of Variable Stars lists its maximum brightness as magnitude 9.1,[14] far too faint to be seen with the naked eye, both AAVSO and ASAS data shows that R Sculptoris is occasionally brighter than 6th magnitude, and faintly visible to the naked eye under excellent observing conditions.[15][16]

A visual band light curve for R Sculptoris, plotted from ASAS data[17]

This is an aging giant star on the asymptotic giant branch with a stellar classification of C6,5ea(Np),[3] which indicates a carbon-rich atmosphere. It is a semi-regular pulsating star of the SRb[4] type that is nearing the end of its fusing lifespan. A sine curve fitted to the last ten pulsation cycles prior to 2017 give a pulsation period of 376 days with an amplitude of 0.75 magnitude. The star is shedding its outer atmosphere, and it is surrounded by a thin shell of dust and gas that was created during the most recent thermal pulse around 2,000 years ago.[6]

Observations have revealed a spiral structure in the material around the star.[18] The spiral is suspected to be caused by an unseen companion star.[11] The spiral windings are consistent with an orbital period of ~350 years.[18]

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  • This image captures approximately 20x20 milliarcseconds.[19]
    This image captures approximately 20x20 milliarcseconds.[19]
  • Spiral spotted by ALMA around the star (data visualisation).
    Spiral spotted by ALMA around the star (data visualisation).
  • R Sculptoris and its hidden companion, taken by Hubble Space Telescope
    R Sculptoris and its hidden companion, taken by Hubble Space Telescope

References

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  1. ^ a b c d e f Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Gaia DR2 record for this source at VizieR.
  2. ^ a b c Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  3. ^ a b c Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  4. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  5. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  6. ^ a b c Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  7. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  8. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  9. ^ a b c Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  10. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  11. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  12. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  13. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  14. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  15. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  16. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  17. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  18. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  19. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).

Further reading

[edit | edit source]
  • Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
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