RS Telescopii

RS Telescopii

A visual band light curve for RS Telescopii, plotted from AAVSO data[1]
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Telescopium
Right ascension	18^h 18^m 51.2224^s[2]
Declination	−46° 32′ 53.427″[2]
Apparent magnitude (V)	10.67[3]
Characteristics
Spectral type	R0
B−V color index	2.100±0.510[3]
Variable type	R CrB[4]
Astrometry
Radial velocity (Rv)	−3.0[3] km/s
Proper motion (μ)	RA: −2.730[2] mas/yr Dec.: −6.670[2] mas/yr
Parallax (π)	0.1732 ± 0.0166 mas[2]
Distance	19,000 ± 2,000 ly (5,800 ± 600 pc)
Details
Radius	73[5] R☉
Luminosity	288 (at max)[6] L☉
Surface gravity (log g)	1.0[7] cgs
Temperature	5,800[6] K
Other designations
RS Tel, CD−46°12279, HIP 89739[8]
Database references
SIMBAD	data

RS Telescopii, abbreviated RS Tel, is a variable star in the southern constellation of Telescopium. It is a dim star with an apparent visual magnitude of 10.67,[3] which is much too faint to be visible without a telescope. The variability of this star was discovered by Evelyn F. Leland and announced by Edward C. Pickering in 1910.[9] It was first studied by Cecilia H. Payne in 1928 at the Harvard College Observatory.[10][11]

This is an R-type carbon star with a class of R0.[12] RS Tel is a typical R Coronae Borealis variable[10]—an extremely hydrogen-deficient supergiant thought to have arisen as the result of the merger of two white dwarfs; fewer than 100 have been discovered as of 2012.[4] It has under 55%[13] the mass of the Sun and an effective temperature of around 5,800 K.[6] The spectrum of the star shows anomalously weak lines of hydrogen, with strong lines of C₂, CN, and neutral carbon.[14]

RS Tel has a maximum magnitude of 9.6 and a minimum magnitude 16.5.[15] The star undergoes large, random variations in brightness on a time scale of thousands of days with no apparent periodicity.[16] The star is surrounded by a circumstellar shell of dust which radiating an infrared excess.[16]

References

1. "Download Data". aavso.org. AAVSO. Retrieved 1 October 2021.
2. Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
3. Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
4. Tisserand, P.; et al. (2012). "The Ongoing Pursuit of R Coronae Borealis Stars: ASAS-3 Survey Strikes Again". Astronomy & Astrophysics. 551: 22. arXiv:1211.2475. Bibcode:2013A&A...551A..77T. doi:10.1051/0004-6361/201220713. S2CID 59060842. A77.
5. Stassun, Keivan G.; et al. (2019-10-01). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467. hdl:1721.1/124721. ISSN 0004-6256. S2CID 166227927.
6. Bergeat, J.; Knapik, A.; Rutily, B. (2002). "Carbon-rich giants in the HR diagram and their luminosity function". Astronomy and Astrophysics. 390 (3): 967. Bibcode:2002A&A...390..967B. doi:10.1051/0004-6361:20020525.
7. Hema, B. P.; Pandey, Gajendra; Lambert, David L. (2012). "The Galactic R Coronae Borealis Stars: The C₂ Swan Bands, the Carbon Problem, and the ^12C/^13C Ratio". The Astrophysical Journal. 747 (2): 102. arXiv:1201.1357. Bibcode:2012ApJ...747..102H. doi:10.1088/0004-637X/747/2/102. S2CID 118653032.
8. "RS Tel". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-12-11.
9. Pickering, Edward C. (March 1910). "20 new variable stars in Harvard Map, Nos. 2, 5, 32, 44 and 53". Astronomische Nachrichten. 184: 5. Bibcode:1910AN....184....5P. doi:10.1002/asna.19101840104.
10. Milone, Luis A. (October 1990). "Identification charts for southern R Coronae Borealis-stars". Astrophysics and Space Science. 172 (2): 263–271. Bibcode:1990Ap&SS.172..263M. doi:10.1007/BF00643318. S2CID 118353230.
11. Payne, Cecilia H. (October 1928). "The R Coronae Type Variables RS Telescopii and Y Muscae". Harvard College Observatory Bulletin. 861: 11–12. Bibcode:1928BHarO.861...11P.
12. Knapp, G.; et al. (May 2001). "Reprocessing the Hipparcos data for evolved giant stars II. Absolute magnitudes for the R-type carbon stars". Astronomy and Astrophysics. 371: 222–232. arXiv:astro-ph/0103141. Bibcode:2001A&A...371..222K. doi:10.1051/0004-6361:20010348. S2CID 18248545.
13. Stasińska, G.; Szczerba, R.; Schmidt, M.; Siódmiak, N. (2006). "Post-AGB stars as testbeds of nucleosynthesis in AGB stars". Astronomy and Astrophysics. 450 (2): 701. arXiv:astro-ph/0601504. Bibcode:2006A&A...450..701S. doi:10.1051/0004-6361:20053553. S2CID 12040452.
14. Bidelman, William P. (January 1953). "The Spectra of Certain Stars whose Atmospheres may be Deficient in Hydrogen". Astrophysical Journal. 117: 25. Bibcode:1953ApJ...117...25B. doi:10.1086/145665.
15. BSJ (11 November 2011). "RX Telescopii". AAVSO Website. American Association of Variable Star Observers. Retrieved 26 June 2014.
16. Feast, M. W.; et al. (February 1997). "The R Coronae Borealis stars - I. Infrared photometry and long-term variations". Monthly Notices of the Royal Astronomical Society. 285 (2): 317–338. Bibcode:1997MNRAS.285..317F. doi:10.1093/mnras/285.2.317.