Astronomy:CH Crucis

From HandWiki
Short description: Star in the constellation Crux
CH Crucis
Location of CH Crucis (circled in red)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Crux[1]
Right ascension  12h 41m 56.56918s[2]
Declination −59° 41′ 08.9544″[2]
Apparent magnitude (V) 4.91[1]
Characteristics
Evolutionary stage subgiant[2]
Spectral type B5III[3] or B6IV[4]
U−B color index −0.37[5]
B−V color index −0.044±0.03[1]
Variable type γ Cas[6]
Astrometry
Radial velocity (Rv)+12.5±2.8[1] km/s
Proper motion (μ) RA: -24.464[2] mas/yr
Dec.: -4.226[2] mas/yr
Parallax (π)3.8643 ± 0.0811[2] mas
Distance840 ± 20 ly
(259 ± 5 pc)
Absolute magnitude (MV)−2.41[1]
Details
Mass5.30±0.27[7] M
Radius11.20±0.22[8] R
Luminosity1,073[1] L
Surface gravity (log g)2.90±0.03[8] cgs
Temperature10,600±106[8] K
Rotational velocity (v sin i)240[9] km/s
Age120[10] Myr
Other designations
Lumbung, CH Cru, CPD−59°4393, HD 110335, HIP 61966, HR 4823, SAO 240161[11]
Database references
SIMBADdata

CH Crucis (39 Crucis), also named Lumbung,[12] is a solitary[13] variable star in the southern constellation of Crux. It has the Gould designation 39 G. Crucis.[14] The object is visible to the naked eye as a faint, blue-white hued point of light with an apparent visual magnitude that fluctuates around 4.91.[1] The star is located 844.02 light years distant from the Sun based on parallax, with an uncertainty of −17.35/+18.09 light years.[15] and is drifting further away with a radial velocity of about +12.5 km/s.[1] It is a member of the nearby Sco OB2 association.[16]

A blue band light curve for CH Crucis, plotted from data published by Balona et al. (1992)[17]

This is a conventional shell star, which is understood to be a Be star that is being viewed edge-on.[18] Houk (1975) found a stellar classification of B5III,[3] while Hiltner et al. assigned it to B6IV;[4] suggesting it is a B-type star that is evolving off the main sequence.[7]Later literature has also listed the star as B6IVe+sh (Yudin 2001)[19] and B8IV (Arcos et al. 2018),[20] while an older source, Buscombe & Morris (1960) [21]classified it as B7IV and identified it as a spectroscopic binary. indicating some variation in its spectral classification in the literature.

Samus et al. (2017) have tentatively classified it as a Gamma Cassiopeiae variable with a brightness range of 4.88–5.7 mag in the Johnson B band.[6]

CH Crucis has 5.3[7] times the mass of the Sun and 11.2[8] times the Sun's radius. It is radiating 1,073[1] times the luminosity of the Sun from its photosphere at an effective temperature of 10,600 K.[8] It is spinning rapidly with estimates of the projected rotational velocity ranging up to 240 or 250 km/s.[18][9] This is giving the star an oblate shape with an equatorial bulge that is an estimated 18% larger than the polar radius.[9]

The IAU Working Group on Star Names approved the name Lumbung for this star on 22 February 2026.[12] Lumbung is a constellation from Bali (Indonesia), corresponding to Crux. The term is inherited from Malay, Proto-Malayo-Polynesian, meaning a rice barn or granary. The constellation of Lumbung is attested for ~1300 years in the cultural calendar and associated with Wednesday and the third day of an Oceanic market cycle.[22]

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode2012AstL...38..331A  XHIP record for this object at VizieR.
  2. 2.0 2.1 2.2 2.3 2.4 2.5 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  3. 3.0 3.1 Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, 1, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode1975mcts.book.....H. 
  4. 4.0 4.1 Hiltner, W. A.; Garrison, R. F.; Schild, R. E. (July 1969), "MK Spectral Types for Bright Southern OB Stars", Astrophysical Journal 157: 313–326, doi:10.1086/150069, Bibcode1969ApJ...157..313H. 
  5. "39 Crucis, a blue subgiant star in Crux", Ashland Astronomy Studio, http://www.astrostudio.org/xhip.php?hip=61966, retrieved 2012-08-23 
  6. 6.0 6.1 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, doi:10.1134/S1063772917010085, Bibcode2017ARep...61...80S. 
  7. 7.0 7.1 7.2 Zorec, J. et al. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy and Astrophysics 537: A120, doi:10.1051/0004-6361/201117691, Bibcode2012A&A...537A.120Z. 
  8. 8.0 8.1 8.2 8.3 8.4 Arcos, C. et al. (March 2018), "Stellar parameters and H α line profile variability of Be stars in the BeSOS survey", Monthly Notices of the Royal Astronomical Society 474 (4): 5287–5299, doi:10.1093/mnras/stx3075, Bibcode2018MNRAS.474.5287A. 
  9. 9.0 9.1 9.2 Belle, G. T. (2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review 20 (1), doi:10.1007/s00159-012-0051-2, Bibcode2012A&ARv..20...51V. 
  10. "HIP 61966", Wolfram Alpha, http://www.wolframalpha.com/input/?i=HIP+61966, retrieved 2012-08-23 
  11. "CH Cru". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=CH+Cru. 
  12. 12.0 12.1 "IAU Catalog of Star Names". https://exopla.net/star-names/modern-iau-star-names/. 
  13. Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869–879, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode2008MNRAS.389..869E. 
  14. Gould, Benjamin Apthorp (1879), "Uranometria Argentina catalog of bright southern stars", Resultados del Observatorio Nacional Argentino 1, Bibcode1879RNAO....1.....G, http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=V%2F135%2Fcatalog, retrieved 2012-05-08. 
  15. Collaboration, Gaia; Vallenari, A.; Brown, A. G. A.; Prusti, T.; de Bruijne, J. H. J.; Arenou, F.; Babusiaux, C.; Biermann, M. et al. (June 2023). "Gaia Data Release 3. Summary of the content and survey properties" (in en). Astronomy and Astrophysics 674: A1. doi:10.1051/0004-6361/202243940. ISSN 0004-6361. Bibcode2023A&A...674A...1G. https://ui.adsabs.harvard.edu/abs/2023A&A...674A...1G/abstract. 
  16. Hoogerwerf, Ronnie (March 2000), "OB association members in the ACT and TRC catalogues", Monthly Notices of the Royal Astronomical Society 313 (1): 43–65, doi:10.1046/j.1365-8711.2000.03192.x, Bibcode2000MNRAS.313...43H. 
  17. Balona, L. A.; Cuypers, J.; Marang, F. (February 1992). "Intensive photometry of southern Be variables. II. Summer objects". Astronomy & Astrophysics Supplement Series 92: 533–563. Bibcode1992A&AS...92..533B. https://ui.adsabs.harvard.edu/abs/1992A&AS...92..533B. Retrieved 18 December 2021. 
  18. 18.0 18.1 Rivinius, Th. et al. (November 2006), "Bright Be-shell stars", Astronomy and Astrophysics 459 (1): 137–145, doi:10.1051/0004-6361:20053008, Bibcode2006A&A...459..137R. 
  19. Yudin, R. V. (March 2001). "Statistical analysis of intrinsic polarization, IR excess and projected rotational velocity distributions of classical Be stars" (in en). Astronomy and Astrophysics 368 (3): 912–931. doi:10.1051/0004-6361:20000577. ISSN 0004-6361. Bibcode2001A&A...368..912Y. https://ui.adsabs.harvard.edu/abs/2001A&A...368..912Y/abstract. 
  20. Arcos, C.; Kanaan, S.; Chávez, J.; Vanzi, L.; Araya, I.; Curé, M. (March 2018). "Stellar parameters and H α line profile variability of Be stars in the BeSOS survey" (in en). Monthly Notices of the Royal Astronomical Society 474 (4): 5287–5299. doi:10.1093/mnras/stx3075. ISSN 0035-8711. Bibcode2018MNRAS.474.5287A. 
  21. Buscombe, W.; Morris, P. M. (1960). "The Scorpio-Centaurus association: I. Radial velocities of 120 bright stars" (in en). Monthly Notices of the Royal Astronomical Society 121 (3): 263–278. doi:10.1093/mnras/121.3.263. ISSN 0035-8711. Bibcode1960MNRAS.121..263B. 
  22. "Lumbung". IAU Working Group on Star Names. https://ase.exopla.net/index.php/Lumbung.