R Crateris

R Crateris is a star about 700 light years from the Earth in the constellation Crater. It is a semiregular variable star, ranging in brightness from magnitude 8.1 to 9.5 over a period of about 160 days.[3] It is not visible to the naked-eye, but can be seen with a small telescope, or binoculars.[11] R Crateris is a double star; the variable star and its magnitude 9.9 F8V companion are separated by 65.4 arcseconds.[12]

R Crateris

A visual band light curve for R Crateris, plotted from ASAS data.[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Crater
Right ascension 11h 00m 33.85257s[2]
Declination −18° 19′ 29.5827″[2]
Apparent magnitude (V) 8.1 - 9.5[3]
Characteristics
Evolutionary stage AGB[4]
Spectral type M7/8III[5]
Variable type SRb[6]
Astrometry
Radial velocity (Rv)20.94±1.50[2] km/s
Proper motion (μ) RA: −29.373±0.180[2] mas/yr
Dec.: −2.499±0.172[2] mas/yr
Parallax (π)4.7027 ± 0.1528 mas[2]
Distance690 ± 20 ly
(213 ± 7 pc)
Details
Mass1.91[7] M☉
Radius633[8] R☉
Luminosity8,151[8] L☉
Surface gravity (log g)−0.86[8] cgs
Temperature3,295[9] K
Other designations
HD 95384, HIP 53809, SAO 156389, IRC −20222, RAFGL 1450[10]
Database references
SIMBADdata

Although the period for large brightness changes in R Crateris is listed as ~160 days, in 1982 Silvia Livi and Thaisa Bergmann reported small (~0.1 magnitude) variations on timescales of less than one hour. The rapid variations seem to be more regular when the star is near maximum brightness.[13]

R Crateris is an oxygen-rich asymptotic giant branch star, losing mass at a rate of 8×10−7 solar masses per year via a stellar wind.[4] At large distances from the star, the wind is expanding into space at 11.7±0.3 km/sec.[14]

Near-infrared radiation from R Crateris was detected in the first Two-Micron Sky Survey, published in 1969.[15] It was detected in the far-infrared by the IRAS satellite, and that emission was resolved by IRAS, showing that the star is surrounded by a large circumstellar shell containing dust.[16] High resolution far-infrared images of R Crateris taken by the Herschel Space Observatory show that the emitting region of the shell, roughly 280 arcseconds (0.94 light year) across, consists primarily of two non-concentric arcs well separated from the star itself. The arcs are probably bowshocks formed as the dusty stellar wind collides with the interstellar medium.[17] The total mass of the shell, including both dust and gas, is estimated to be about (6.4±2)×10−2 solar masses.[18] Infrared imaging of the innermost (sub-arcsecond) portion of the dust shell shows a bipolar structure.[4][19]

In the early 1970s, maser emission from OH and H2O was detected in R Cratoris' circumstellar shell.[20] SiO maser emission was detected in 1985.[21] Thermal (non-maser) emission from CO was detected in 1986.[22]

With the high angular resolution provided by Very Long Baseline Interferometry, the H2O maser emission is seen to arise from small (milli-arcsecond) blobs, whose proper motions through the inner region of the circumstellar shell can be measured. These observations give additional evidence that R Cratoris has developed a bipolar stellar wind.[23]

References
  1. "ASAS All Star Catalogue". The All Sky Automated Survey. Retrieved 24 March 2023.
  2. 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. Jura, M.; Kleinmann, S. G. (December 1992). "Oxygen-rich Semiregular and Irregular Variables". Astrophysical Journal Supplement. 83: 329–349. Bibcode:1992ApJS...83..329J. doi:10.1086/191740. Retrieved 24 March 2023.
  4. Khouri, T.; Vlemmings, W. H. T.; Paladini, C.; Ginski, C.; Lagadec, E.; Maercker, M.; Kervella, P.; De Beck, E.; Decin, L.; de Koter, A.; Waters, L. B. F. M. (March 2020). "Inner dusty envelope of the AGB stars W Hydrae, SW Virginis, and R Crateris using SPHERE/ZIMPOL". Astronomy and Astrophysics. 635: A200. arXiv:2003.06195. Bibcode:2020A&A...635A.200K. doi:10.1051/0004-6361/201834618. S2CID 212717963. Retrieved 24 March 2023.
  5. Houk, N.; Smith-Moore, M. (1988). Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Volume 4, Declinations -26°.0 to -12°.0. University of Michigan, Ann Arbor, MI. Bibcode:1988mcts.book.....H. ISBN 0835703312.
  6. Samus', N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports. 61 (1): 80. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869.
  7. Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric (2022). "Stellar and substellar companions from Gaia EDR3". Astronomy & Astrophysics. 657: A7. arXiv:2109.10912. Bibcode:2022A&A...657A...7K. doi:10.1051/0004-6361/202142146. S2CID 237605138.
  8. McDonald, I.; Zijlstra, A. A.; Watson, R. A. (October 2017). "Fundamental parameters and infrared excesses of Tycho-Gaia stars". Monthly Notices of the Royal Astronomical Society. 471 (1): 770–791. arXiv:1706.02208. Bibcode:2017MNRAS.471..770M. doi:10.1093/mnras/stx1433. ISSN 0035-8711.
  9. Tonry, J. L.; Denneau, L.; Flewelling, H.; Heinze, A. N.; Onken, C. A.; Smartt, S. J.; Stalder, B.; Weiland, H. J.; Wolf, C. (2018). "The ATLAS All-Sky Stellar Reference Catalog". The Astrophysical Journal. 867 (2): 105. arXiv:1809.09157. Bibcode:2018ApJ...867..105T. doi:10.3847/1538-4357/aae386. S2CID 118959775.
  10. "V* R Crt -- Asymptotic Giant Branch Star". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2023-03-24.
  11. Taylor, Melvyn. "Observing Variable Stars with Binoculars" (PDF). British Astronomical Association. Retrieved 24 March 2023.
  12. Halbedel, E. M. (May 1985). "Spectral types of companions to variable visual double stars". Publications of the Astronomical Society of the Pacific. 97: 434–436. Bibcode:1985PASP...97..434H. doi:10.1086/131557. S2CID 119628081. Retrieved 24 March 2023.
  13. Livi, S. H. B.; Bergmann, T. S. (December 1982). "Rapid optical variation of the semiregular variable R Crt". Astronomical Journal. 87: 1783–1790. Bibcode:1982AJ.....87.1783L. doi:10.1086/113267. Retrieved 24 March 2023.
  14. Brand, J.; Engels, D.; Winnberg, A. (December 2020). "Water vapour masers in long-period variable stars. II. The semi-regular variables R Crt and RT Vir" (PDF). Astronomy and Astrophysics. 644: A45. arXiv:2011.00294. Bibcode:2020A&A...644A..45B. doi:10.1051/0004-6361/202039157. Retrieved 24 March 2023.
  15. Neugebauer, G.; Leighton, R. B. (1969). Two-micron sky survey. A preliminary catalogue. NASA. Bibcode:1969tmss.book.....N. Retrieved 24 March 2023.
  16. Young, K.; Phillips, T. G.; Knapp, G. R. (June 1993). "Circumstellar Shells Resolved in the IRAS Survey Data. I. Data Processing Procedure, Results, and Confidence Tests". Astrophysical Journal Supplement. 86: 517–640. Bibcode:1993ApJS...86..517Y. doi:10.1086/191789.
  17. Cox, N. L. J.; Kerschbaum, F.; van Marle, A. J.; Decin, L.; Ladjal, D.; Mayer, A.; Groenewegen, M. A. T.; van Eck, S.; Royer, P.; Ottensamer, R.; Ueta, T.; Jorissen, A.; Mecina, M.; Meliani, Z.; Luntzer, A.; Blommaert, J. A. D. L.; Posch, Th.; Vandenbussche, B.; Waelkens, C. (January 2012). "A far-infrared survey of bow shocks and detached shells around AGB stars and red supergiants" (PDF). Astronomy and Astrophysics. 537: A35. arXiv:1110.5486. Bibcode:2012A&A...537A..35C. doi:10.1051/0004-6361/201117910. S2CID 56041336. Retrieved 24 March 2023.
  18. Cox, N. L. J.; Kerschbaum, F.; van Marle, A. J.; Decin, L.; Ladjal, D.; Mayer, A.; Groenewegen, M. A. T.; van Eck, S.; Royer, P.; Ottensamer, R.; Ueta, T.; Jorissen, A.; Mecina, M.; Meliani, Z.; Luntzer, A.; Blommaert, J. A. D. L.; Posch, Th.; Vandenbussche, B.; Waelkens, C. (July 2012). "A far-infrared survey of bow shocks and detached shells around AGB stars and red supergiants (Corrigendum)". Astronomy and Astrophysics. 543: C1. Bibcode:2012A&A...543C...1C. doi:10.1051/0004-6361/201117910e. Retrieved 24 March 2023.
  19. Paladini, C.; Klotz, D.; Sacuto, S.; Lagadec, E.; Wittkowski, M.; Richichi, A.; Hron, J.; Jorissen, A.; Groenewegen, M. A. T.; Kerschbaum, F.; Verhoelst, T.; Rau, G.; Olofsson, H.; Zhao-Geisler, R.; Matter, A. (April 2017). "The VLTI/MIDI? view on the inner mass loss of evolved stars from the Herschel MESS sample". Astronomy and Astrophysics. 600: A136. arXiv:1701.05407. Bibcode:2017A&A...600A.136P. doi:10.1051/0004-6361/201527210. S2CID 55806390. Retrieved 24 March 2023.
  20. Dickinson, D. F.; Bechis, K. P.; Barrett, A. H. (March 1973). "New H2O sources associated with infrared stars". Astrophysical Journal. 180: 831. Bibcode:1973ApJ...180..831D. doi:10.1086/152010. Retrieved 24 March 2023.
  21. Jewell, P. R.; Walmsley, C. M.; Wilson, T. L.; Snyder, L. E. (November 1985). "New detections of maser and thermal SiO emission". Astrophysical Journal. 298: L55–L59. Bibcode:1985ApJ...298L..55J. doi:10.1086/184566. Retrieved 24 March 2023.
  22. Zuckerman, B.; Dyck, H. M. (May 1986). "Carbon Monoxide Emission from Stars in the IRAS and Revised AFGL Catalogs. I. Mass Loss Driven by Radiation Pressure on Dust Grains". Astrophysical Journal. 304: 394. Bibcode:1986ApJ...304..394Z. doi:10.1086/164173. Retrieved 24 March 2023.
  23. Ishitsuka, Jose K.; Imai, Hiroshi; Omodaka, Toshihiro; Ueno, Munetaka; Kameya, Osamu; Sasao, Tetsuo; Morimoto, Masaki; Miyaji, Takeshi; Nakajima, Jun-Ichi; Watanabe, Teruhiko (December 2001). "VLBI Monitoring Observations of Water Masers around the Semi-Regular Variable Star R Crateris". Publications of the Astronomical Society of Japan. 53 (6): 1231–1238. arXiv:astro-ph/0112302. Bibcode:2001PASJ...53.1231I. doi:10.1093/pasj/53.6.1231. Retrieved 25 March 2023.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.