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

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]

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. 1 2 3 4 5 6 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 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. 1 2 3 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. 1 2 3 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.
  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.
  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.
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