LL Pegasi

LL Pegasi
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Pegasus
Right ascension 23h 19m 12.607s[1]
Declination +17° 11′ 33.13″[1]
Characteristics
Evolutionary stage AGB[2]
Spectral type C[3]
Variable type Mira[4]
Astrometry
Distance1,300[2] pc
Details
Radius608[2]-869[5] R☉
Luminosity11,000[2] L☉
Temperature2,000[5]-2,400[2] K
Other designations
LL Pegasi, IRAS 23166+1655, 2MASS J23191260+1711331, RAFGL 3068
Database references
SIMBADdata

LL Pegasi (AFGL 3068) is a Mira variable star surrounded by a pinwheel-shaped nebula, IRAS 23166+1655, thought to be a preplanetary nebula. It is a binary system that includes an extreme carbon star. The pair is hidden by the dust cloud ejected from the carbon star and is only visible in infrared light.[6]

Variability

LL Pegasi is obscured at visual wavelengths, but is strongly variable in brightness at infrared wavelengths.[7] It is classified as a Mira variable and has a period of about 696 days.[8]

Nebula

The nebula displays an unusual spiral shape. The shape is thought to be formed through the interaction between the stellar companion and the carbon star, as has been seen in other binary systems, although not with such a precise geometric form. The distance between the spiral arms and their rate of expansion is consistent with estimates of the pair's 810 year orbital period based on their apparent angular separation.[6]

References

  1. 1 2 Cutri, R. M.; Skrutskie, M. F.; Van Dyk, S.; Beichman, C. A.; Carpenter, J. M.; Chester, T.; Cambresy, L.; Evans, T.; Fowler, J.; Gizis, J.; Howard, E.; Huchra, J.; Jarrett, T.; Kopan, E. L.; Kirkpatrick, J. D.; Light, R. M.; Marsh, K. A.; McCallon, H.; Schneider, S.; Stiening, R.; Sykes, M.; Weinberg, M.; Wheaton, W. A.; Wheelock, S.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". VizieR On-line Data Catalog: II/246. Originally published in: 2003yCat.2246....0C. 2246. Bibcode:2003yCat.2246....0C.
  2. 1 2 3 4 5 Lombaert, R.; De Vries, B. L.; De Koter, A.; Decin, L.; Min, M.; Smolders, K.; Mutschke, H.; Waters, L. B. F. M. (2012). "Observational evidence for composite grains in an AGB outflow. MgS in the extreme carbon star LL Pegasi". Astronomy & Astrophysics. 544: L18. arXiv:1207.1606. Bibcode:2012A&A...544L..18L. doi:10.1051/0004-6361/201219782.
  3. ↑ Groenewegen, M. A. T.; De Jong, T.; Gaballe, T. R. (1994). "The 3 micrometer spectra of candidate carbon stars". Astronomy and Astrophysics (ISSN 0004-6361). 287: 163. Bibcode:1994A&A...287..163G.
  4. ↑ Samus, 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. Bibcode:2009yCat....102025S.
  5. 1 2 De Beck, E.; Decin, L.; De Koter, A.; Justtanont, K.; Verhoelst, T.; Kemper, F.; Menten, K. M. (2010). "Probing the mass-loss history of AGB and red supergiant stars from CO rotational line profiles. II. CO line survey of evolved stars: Derivation of mass-loss rate formulae". Astronomy and Astrophysics. 523: A18. arXiv:1008.1083. Bibcode:2010A&A...523A..18D. doi:10.1051/0004-6361/200913771.
  6. 1 2 Morris, Mark; Sahai, Raghvendra; Matthews, Keith; Cheng, Judy; Lu, Jessica; Claussen, Mark; Sánchez-Contreras, Carmen (2006). "A Binary-Induced Pinwheel Outflow from the Extreme Carbon Star, AFGL 3068". Planetary Nebulae in our Galaxy and Beyond. 234: 469. Bibcode:2006IAUS..234..469M. doi:10.1017/S1743921306003784.
  7. ↑ Le Bertre, T. (1992). "Carbon-star lightcurves in the 1-20 micron range". Astronomy and Astrophysics Supplement Series (ISSN 0365-0138). 94: 377. Bibcode:1992A&AS...94..377L.
  8. ↑ Whitelock, Patricia A.; Feast, Michael W.; Marang, Freddy; Groenewegen, M. A. T. (2006). "Near-infrared photometry of carbon stars". Monthly Notices of the Royal Astronomical Society. 369 (2): 751. arXiv:astro-ph/0603504. Bibcode:2006MNRAS.369..751W. doi:10.1111/j.1365-2966.2006.10322.x.
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