R Sculptoris

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]
Distance1177±143 ly
(361±44 pc)[6]
Absolute magnitude (MV)−0.45[7]
Details[8]
Mass1.3±0.7 M☉
Radius355±55,[8] 513[9] R☉
Luminosity5,495+2,822
−1,865 L☉
Surface gravity (log g)−0.6±0.4 cgs
Temperature2640±80 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]

A visual band light curve for R Sculptoris, plotted from ASAS data[13]

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.[14] 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.[14]

  1. ^ a b c d e f Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference ducati2002 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference cruzalebes_et_al_2013 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference gcvs was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference Maercker2018 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Anderson_Francis_2012 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference wittkowski_et_al_2017 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference cruzalebes-2013 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference SpaceDaily-2015-01-11 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference eso1239a was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference ASASServer was invoked but never defined (see the help page).
  14. ^ a b Cite error: The named reference Maercker_et_al_2012 was invoked but never defined (see the help page).