S Cassiopeiae

Last updated
S Cassiopeiae
Cassiopeia constellation map.svg
Location of S Cas

S Cassiopeiae in 2MASS
Credit: SIMBAD Astronomical Database
Observation data
Epoch J2000       Equinox J2000
Constellation Cassiopeia [1]
Right ascension 01h 19m 41.980s [2]
Declination 72° 36′ 40.85″ [2]
Apparent magnitude  (V)+7.9 – +16.1 [3]
Characteristics
Evolutionary stage AGB [4]
Spectral type S3,4 – S5,8 [5]
Variable type Mira [3]
Astrometry
Proper motion (μ)RA: 1.980 [2] mas/yr
Dec.: 1.515 [2] mas/yr
Parallax (π)1.0515±0.0907  mas [2]
Distance 3,100 ± 300  ly
(950 ± 80  pc)
Details
Mass 4.1 [6]   M☉
Radius 930 [7]   R☉
Luminosity 5,210 [8]   L☉
Surface gravity (log g)1.32 [6]   cgs
Temperature 1,800 [9]   K
Metallicity [Fe/H]−0.51 [6]   dex
Other designations
S  Cas, HD  7769, BD+71°66, 2MASS  J01194198+7236407, GSC  04305-01322, IRAS  01159+7220, IRC+70024, AAVSO  0112+72
Database references
SIMBAD data

S Cassiopeiae (S Cas, HD 7769) is a Mira variable and S-type star in the constellation Cassiopeia. It is an unusually cool star, rapidly losing mass and surrounded by dense gas and dust producing masers.

Contents

Distance

In the absence of a measurement of its parallax by the Hipparcos satellite, its distance from the Solar System was estimated between 1,860 and 2,770 light-years. [9] [10] Gaia Data Release 3 published a parallax of 1.0515±0.0907  mas , indicating a distance around 950  pc , [11] but the observations have a very high noise level and are considered unreliable. An independent calculation from a period-luminosity relation gives a distance of 880 pc. [4]

Spectral type

With a spectral type of S3,4e-S5,8e, S Cassiopeiae is an S-type star similar to χ Cygni; these are asymptotic giant branch (AGB) stars similar to those of class M except that the dominant spectral bands of metal oxides are formed by metals of the fifth period of the periodic table as zirconium or yttrium. Another feature of this class of stars is the high mass loss; in the case of S Cassiopeiae it is estimated at 1.8×10−6 M☉ per year. [8]

Characteristics

The visual band light curve of S Cassiopeiae, from AAVSO data SCasLightCurve.png
The visual band light curve of S Cassiopeiae, from AAVSO data

S Cassiopeiae has a radius of 934 solar radii; if placed at the center of the Solar System, it would extend past the orbit of Mars and the Asteroid Belt. Its effective temperature is 1,800 K, [9] which is possibly a late thermal pulse asymptotic giant branch red giant star near the tip of its evolution, after this, it may enter its white dwarf phase after it sheds its outer layers or shrinks and gets hotter to a possibly orange giant. Its surface temperature is exceptionally cool for any star other than the brown dwarfs, and its bolometric luminosity is 5,210 times that of the sun. [8]

S Cassiopeiae is a variable Mira, a pulsating variable star whose visual brightness varies over several magnitudes with a somewhat regular period and amplitude. Its visual magnitude varies between +7.9 and +16.1 over an average period of 612.43 days. Mira variables are stars in the last stages of evolution whose instability comes from pulsations in their surfaces, causing changes in color and brightness. Some of them, including S Cassiopeiae show SiO maser emission. [13]

See also

References

  1. ↑ Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331–346. arXiv: 1108.4971 . Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. eISSN   1562-6873. ISSN   1063-7737. S2CID   119257644.
  2. 1 2 3 4 5 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  3. 1 2 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.
  4. 1 2 Andriantsaralaza, M.; Ramstedt, S.; Vlemmings, W. H. T.; De Beck, E. (2022). "Distance estimates for AGB stars from parallax measurements". Astronomy and Astrophysics. 667: A74. arXiv: 2209.03906 . Bibcode:2022A&A...667A..74A. doi:10.1051/0004-6361/202243670.
  5. ↑ Ramstedt, S.; Schöier, F. L.; Olofsson, H.; Lundgren, A. A. (2006). "Mass-loss properties of S-stars on the AGB". Astronomy and Astrophysics . 454 (2): L103. arXiv: astro-ph/0605664 . Bibcode:2006A&A...454L.103R. doi:10.1051/0004-6361:20065285. S2CID   119080381.
  6. 1 2 3 Khalatyan, A.; Anders, F.; Chiappini, C.; Queiroz, A. B. A.; Nepal, S.; Dal Ponte, M.; Jordi, C.; Guiglion, G.; Valentini, M.; Torralba Elipe, G.; Steinmetz, M.; Pantaleoni-González, M.; Malhotra, S.; Jiménez-Arranz, Ó.; Enke, H.; Casamiquela, L.; Ardèvol, J. (2024). "Transferring spectroscopic stellar labels to 217 million Gaia DR3 XP stars with SHBoost". Astronomy and Astrophysics. 691: A98. arXiv: 2407.06963 . Bibcode:2024A&A...691A..98K. doi:10.1051/0004-6361/202451427.
  7. ↑ Ramstedt, S.; Schöier, F. L.; Olofsson, H. (2009). "Circumstellar molecular line emission from S-type AGB stars: mass-loss rates and SiO abundances". Astronomy and Astrophysics . 499 (2): 515–527. arXiv: 0903.1672 . Bibcode:2009A&A...499..515R. doi:10.1051/0004-6361/200911730. S2CID   17942939. 515-527.
  8. 1 2 3 McDonald, I.; De Beck, E.; Zijlstra, A. A.; Lagadec, E. (2018). "Pulsation-triggered dust production by asymptotic giant branch stars". Monthly Notices of the Royal Astronomical Society. 481 (4): 4984. arXiv: 1809.07965 . Bibcode:2018MNRAS.481.4984M. doi: 10.1093/mnras/sty2607 . S2CID   118969263.
  9. 1 2 3 Ramstedt, S.; Olofsson, H. (2014). "The 12CO/13CO ratio in AGB stars of different chemical type. Connection to the 12C/13C ratio and the evolution along the AGB". Astronomy & Astrophysics. 566: A145. arXiv: 1405.6404 . Bibcode:2014A&A...566A.145R. doi:10.1051/0004-6361/201423721. S2CID   59125036.
  10. ↑ Guandalini, R.; Busso, M. (2008). "Infrared photometry and evolution of mass-losing AGB stars. II. Luminosity and colors of MS and S stars". Astronomy and Astrophysics . 488 (2): 675–684. arXiv: 0806.4591 . Bibcode:2008A&A...488..675G. doi:10.1051/0004-6361:200809932. S2CID   14294870.
  11. ↑ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics . 616. A1. arXiv: 1804.09365 . Bibcode: 2018A&A...616A...1G . doi: 10.1051/0004-6361/201833051 . Gaia DR2 record for this source at VizieR.
  12. ↑ "Download Data". aavso.org. AAVSO. Retrieved 1 October 2021.
  13. ↑ Herpin, F.; Baudry, A.; Thum, C.; Morris, D.; Wiesemeyer, H. (2006). "Full polarization study of SiO masers at 86 GHz". Astronomy and Astrophysics. 450 (2): 667–680. arXiv: astro-ph/0601098 . Bibcode:2006A&A...450..667H. doi:10.1051/0004-6361:20054255. S2CID   17330694.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.