Astronomy:Lambda Crucis
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Crux |
| Right ascension | 12h 54m 39.18258s[1] |
| Declination | −59° 08′ 48.1229″[1] |
| Apparent magnitude (V) | 4.62[2] |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | B4 Vne[3] |
| U−B color index | −0.60[4] |
| B−V color index | −0.15[4] |
| Variable type | β Cep?[2] |
| Astrometry | |
| Radial velocity (Rv) | +12.0±4.2[5] km/s |
| Proper motion (μ) | RA: −32.92[1] mas/yr Dec.: −14.60[1] mas/yr |
| Parallax (π) | 8.50 ± 0.21[1] mas |
| Distance | 384 ± 9 ly (118 ± 3 pc) |
| Absolute magnitude (MV) | −1.2[6] |
| Details | |
| Mass | 5.0±0.1[7] M☉ |
| Radius | 3.00[8] R☉ |
| Luminosity | 790[6] L☉ |
| Surface gravity (log g) | 3.01[8] cgs |
| Temperature | 16,500[8] K |
| Rotational velocity (v sin i) | 290[8] km/s |
| Age | 53.3±8.1[7] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
λ Crucis, Latinized as Lambda Crucis, is a single,[10] variable star in the southern constellation Crux, near the constellation border with Centaurus. It is visible to the naked eye as a faint, blue-white hued point of light with an apparent visual magnitude that fluctuates around 4.62.[2] The star is located approximately 384 light-years distant from the Sun based on parallax, and is drifting further away with a radial velocity of +12 km/s.[5] It is a proper motion member of the Lower Centaurus–Crux sub-group in the Scorpius–Centaurus OB association, the nearest such association of co-moving massive stars to the Sun.[6]
λ Crucis is listed in the General Catalogue of Variable Stars as a possible β Cephei-type variable. Its brightness varies with an amplitude of 0m.02 over a period of 0.3951 days.[2] However, it is currently thought more likely to be a different type of variable,[12] possibly a λ Eridani variable or rotating ellipsoidal variable.[13][14]
This object is a B-type main-sequence star with a stellar classification of B4 Vne,[3] where the suffix notation indicates "nebulous" (broad) lines due to rapid rotation, along with emission lines from circumstellar material, making it a Be star.[13] It is around 53[7] million years old and is spinning rapidly with a projected rotational velocity of 341 km/s.[15] The star has five[7] times the mass of the Sun and about 3.0[8] times the Sun's radius. It is radiating 790[6] times the luminosity of the Sun from its photosphere at an effective temperature of 16,500 K.[8]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 2.3 Samus, N. N. et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. 5.1 61 (1): 80–88. doi:10.1134/S1063772917010085. Bibcode: 2017ARep...61...80S. http://www.sai.msu.su/gcvs/gcvs/. Retrieved 2019-09-16.
- ↑ 3.0 3.1 Levenhagen, R. S.; Leister, N. V. (2006). "Spectroscopic analysis of southern B and Be stars". Monthly Notices of the Royal Astronomical Society 371 (1): 252–262. doi:10.1111/j.1365-2966.2006.10655.x. Bibcode: 2006MNRAS.371..252L.
- ↑ 4.0 4.1 Johnson, H. L. et al. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory 4 (99): 99. Bibcode: 1966CoLPL...4...99J.
- ↑ 5.0 5.1 Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". in Batten, Alan Henry; Heard, John Frederick. University of Toronto: International Astronomical Union. Bibcode: 1967IAUS...30...57E.
- ↑ 6.0 6.1 6.2 6.3 de Geus, E. J. et al. (June 1989). "Physical parameters of stars in the Scorpio-Centaurus OB association". Astronomy and Astrophysics 216 (1–2): 44–61. Bibcode: 1989A&A...216...44D.
- ↑ 7.0 7.1 7.2 7.3 Tetzlaff, N. et al. (January 2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society 410 (1): 190–200. doi:10.1111/j.1365-2966.2010.17434.x. Bibcode: 2011MNRAS.410..190T.
- ↑ 8.0 8.1 8.2 8.3 8.4 8.5 Arcos, C.; Kanaan, S.; Chávez, J.; Vanzi, L.; Araya, I.; Curé, M. (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. Bibcode: 2018MNRAS.474.5287A.
- ↑ "lam Cru". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=lam+Cru.
- ↑ Rizzuto, A. C. et al. (December 2013). "Long-baseline interferometric multiplicity survey of the Sco-Cen OB association". Monthly Notices of the Royal Astronomical Society 436 (2): 1694–1707. doi:10.1093/mnras/stt1690. Bibcode: 2013MNRAS.436.1694R.
- ↑ "Light Curve". ESA. https://www.cosmos.esa.int/web/hipparcos/java-tools/light-curve.
- ↑ Stankov, Anamarija; Handler, Gerald (2005). "Catalog of Galactic β Cephei Stars". The Astrophysical Journal Supplement Series 158 (2): 193–216. doi:10.1086/429408. Bibcode: 2005ApJS..158..193S.
- ↑ 13.0 13.1 Balona, L. A. (1995). "Tests of the pulsation and starspot models for the periodic be stars". Monthly Notices of the Royal Astronomical Society 277 (4): 1547–1554. doi:10.1093/mnras/277.4.1547. Bibcode: 1995MNRAS.277.1547B.
- ↑ Morris, S. L. (1985). "The ellipsoidal variable stars". The Astrophysical Journal 295: 143. doi:10.1086/163359. Bibcode: 1985ApJ...295..143M.
- ↑ Uesugi, Akira; Fukuda, Ichiro (1970). "Catalogue of rotational velocities of the stars". Contributions from the Institute of Astrophysics and Kwasan Observatory (University of Kyoto). Bibcode: 1970crvs.book.....U.
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