Global InformationEta Carinae information
 The Homunculus Nebula, surrounding Eta Carinae, imaged by WFPC2 at red and near-ultraviolet wavelengths Credit: Jon Morse (University of Colorado) & NASA Hubble Space Telescope | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Carina |
| Right ascension | 10h 45m 03.591s[1] |
| Declination | −59° 41′ 04.26″[1] |
| Apparent magnitude (V) | −1.0 to ~7.6[2] 4.8 (2011) 4.6 (2013) 4.3 (2018) |
| Characteristics | |
| Evolutionary stage | Luminous blue variable |
| Spectral type | variable[3] (LBV) + O (WR?)[4][5] |
| Apparent magnitude (U) | 6.37[6] |
| Apparent magnitude (B) | 6.82[6] |
| Apparent magnitude (R) | 4.90[6] |
| Apparent magnitude (J) | 3.39[6] |
| Apparent magnitude (H) | 2.51[6] |
| Apparent magnitude (K) | 0.94[6] |
| U−B colour index | −0.45[6] |
| B−V colour index | +0.61[6] |
| Variable type | LBV[7] & binary[8] |
| Astrometry | |
| Radial velocity (Rv) | −125.0[9] km/s |
| Proper motion (μ) | RA: −17.6[1] mas/yr Dec.: 1.0[1] mas/yr |
| Distance | 7,500 ly (2,300[10] pc) |
| Absolute magnitude (MV) | −8.6 (2012)[11] |
| Orbit | |
| Primary | η Car A |
| Companion | η Car B |
| Period (P) | 2,022.7±1.3 days[12] (5.54 yr) |
| Semi-major axis (a) | 15.4[13] AU |
| Eccentricity (e) | 0.9[14] |
| Inclination (i) | 130–145[13]° |
| Periastron epoch (T) | 2009.03[15] |
| Details | |
| η Car A | |
| Mass | ~100[10] M☉ |
| Radius | ~240[16] (60[a] – 881[b])[17] R☉ |
| Luminosity | 4.6 million[10] (2.96 million – 4.1 million[18]) L☉ |
| Temperature | 9,400–35,200[19] K |
| Age | <3[5] Myr |
| η Car B | |
| Mass | 30–80[15] M☉ |
| Radius | 14.3–23.6[15] R☉ |
| Luminosity | <1 million[4][5] L☉ |
| Temperature | 37,200[4] K |
| Age | <3[5] Myr |
| Other designations | |
Foramen,[20] Tseen She,[21] 231 G Carinae,[22] HR 4210, HD 93308, CD−59°2620, IRAS 10431-5925, GC 14799, AAVSO 1041–59 | |
| Database references | |
| SIMBAD | data |
Eta Carinae (η Carinae, abbreviated to η Car), formerly known as Eta Argus, is a stellar system containing at least two stars with a combined luminosity greater than five million times that of the Sun, located around 7,500 light-years (2,300 parsecs) distant in the constellation Carina. Previously a 4th-magnitude star, it brightened in 1837 to become brighter than Rigel, marking the start of its so-called "Great Eruption". It became the second-brightest star in the sky between 11 and 14 March 1843 before fading well below naked-eye visibility after 1856. In a smaller eruption, it reached 6th magnitude in 1892 before fading again. It has brightened consistently since about 1940, becoming brighter than magnitude 4.5 by 2014.
At declination −59° 41′ 04.26″, Eta Carinae is circumpolar from locations on Earth south of latitude 30°S (for reference, the latitude of Johannesburg is 26°12′S), and is not visible north of about latitude 30°N, just south of Cairo, which is at a latitude of 30°2′N.
The two main stars of the Eta Carinae system have an eccentric orbit with a period of 5.54 years. The primary is an extremely unusual star, similar to a luminous blue variable (LBV). It was initially 150–250 M☉, of which it has already lost at least 30 M☉, and it is expected to explode as a supernova in the astronomically near future. This is the only star known to produce ultraviolet laser emission. The secondary star is hot and also highly luminous, probably of spectral class O, around 30–80 times as massive as the Sun. The system is heavily obscured by the Homunculus Nebula, which consists of material ejected from the primary during the Great Eruption. It is a member of the Trumpler 16 open cluster within the much larger Carina Nebula.
Although unrelated to the star and nebula, the weak Eta Carinids meteor shower has a radiant very close to Eta Carinae.
- ^ a b c d Høg, E.; Fabricius, C.; Makarov, V.V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27. Bibcode:2000A&A...355L..27H. doi:10.1888/0333750888/2862. ISBN 0-333-75088-8.
- ^ Cite error: The named reference
frewwas invoked but never defined (see the help page). - ^ Skiff, B.A. (2014). "VizieR Online Data Catalog: Catalogue of Stellar Spectral Classifications (Skiff, 2009–2014)". VizieR On-line Data Catalog: B/Mk. Originally Published in: Lowell Observatory (October 2014). 1: 2023. Bibcode:2014yCat....1.2023S.
- ^ a b c Verner, E.; Bruhweiler, F.; Gull, T. (2005). "The Binarity of η Carinae Revealed from Photoionization Modeling of the Spectral Variability of the Weigelt Blobs B and D". The Astrophysical Journal. 624 (2): 973–982. arXiv:astro-ph/0502106. Bibcode:2005ApJ...624..973V. doi:10.1086/429400. S2CID 18166928.
- ^ a b c d Mehner, Andrea; Davidson, Kris; Ferland, Gary J.; Humphreys, Roberta M. (2010). "High-excitation Emission Lines near Eta Carinae, and Its Likely Companion Star". The Astrophysical Journal. 710 (1): 729–742. arXiv:0912.1067. Bibcode:2010ApJ...710..729M. doi:10.1088/0004-637X/710/1/729. S2CID 5032987.
- ^ a b c d e f g h Ducati, J. R. (2002). "VizieR On-line Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237: 0. Bibcode:2002yCat.2237....0D.
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impostorswas invoked but never defined (see the help page). - ^ Cite error: The named reference
damineliwas invoked but never defined (see the help page). - ^ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington: 0. Bibcode:1953GCRV..C......0W.
- ^ a b c Mehner, A.; De Wit, W.-J.; Asmus, D.; Morris, P.W.; Agliozzo, C.; Barlow, M.J.; Gull, T.R.; Hillier, D.J.; Weigelt, G. (2019). "Mid-infrared evolution of η Carinae from 1968 to 2018". Astronomy & Astrophysics. 630: L6. arXiv:1908.09154. Bibcode:2019A&A...630L...6M. doi:10.1051/0004-6361/201936277. S2CID 202149820.
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smithfrewwas invoked but never defined (see the help page). - ^ Damineli, A.; Hillier, D.J.; Corcoran, M.F.; Stahl, O.; Levenhagen, R.S.; Leister, N.V.; Groh, J.H.; Teodoro, M.; Albacete Colombo, J.F.; Gonzalez, F.; Arias, J.; Levato, H.; Grosso, M.; Morrell, N.; Gamen, R.; Wallerstein, G.; Niemela, V. (2008). "The periodicity of the η Carinae events". Monthly Notices of the Royal Astronomical Society. 384 (4): 1649. arXiv:0711.4250. Bibcode:2008MNRAS.384.1649D. doi:10.1111/j.1365-2966.2007.12815.x. S2CID 14624515.
- ^ a b Cite error: The named reference
madurawas invoked but never defined (see the help page). - ^ Damineli, Augusto; Conti, Peter S.; Lopes, Dalton F. (1997). "Eta Carinae: A long period binary?". New Astronomy. 2 (2): 107. Bibcode:1997NewA....2..107D. doi:10.1016/S1384-1076(97)00008-0.
- ^ a b c Kashi, A.; Soker, N. (2010). "Periastron Passage Triggering of the 19th Century Eruptions of Eta Carinae". The Astrophysical Journal. 723 (1): 602–611. arXiv:0912.1439. Bibcode:2010ApJ...723..602K. doi:10.1088/0004-637X/723/1/602. S2CID 118399302.
- ^ Gull, T.R.; Damineli, A. (2010). "JD13 – Eta Carinae in the Context of the Most Massive Stars". Proceedings of the International Astronomical Union. 5: 373–398. arXiv:0910.3158. Bibcode:2010HiA....15..373G. doi:10.1017/S1743921310009890. S2CID 1845338.
- ^ Cite error: The named reference
hillierwas invoked but never defined (see the help page). - ^ Morris, Patrick W.; Gull, Theodore R.; Hillier, D. John; Barlow, M.J.; Royer, Pierre; Nielsen, Krister; Black, John; Swinyard, Bruce (2017). "η Carinae's Dusty Homunculus Nebula from Near-infrared to Submillimeter Wavelengths: Mass, Composition, and Evidence for Fading Opacity". The Astrophysical Journal. 842 (2): 79. arXiv:1706.05112. Bibcode:2017ApJ...842...79M. doi:10.3847/1538-4357/aa71b3. PMC 7323744. PMID 32601504. S2CID 27906029.
- ^ Cite error: The named reference
grohwas invoked but never defined (see the help page). - ^ Gater, Will; Vamplew, Anton; Mitton, Jacqueline (June 2010). The practical astronomer. Dorling Kindersley. ISBN 978-1-4053-5620-6.
- ^ Allen, Richard Hinckley (1963). Star Names: Their Lore and Meaning. Dover Publications. p. 73. ISBN 978-0-486-21079-7.
- ^ Gould, Benjamin Apthorp (1879). "Uranometria Argentina: Brillantez Y posicion de las estrellas fijas, hasta la septima magnitud, comprendidas dentro de cien grados del polo austral: Con atlas". Resultados del Observatorio Nacional Argentino en Cordoba. 1. Bibcode:1879RNAO....1.....G.
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