Epoch J2000.0 Equinox J2000.0
|Right ascension||09h 45m 14.81122s|
|Declination||–62° 30′ 28.4519″|
|Apparent magnitude (V)||3.39|
|Spectral type||G5 Iab/Ib|
|U−B color index||+0.76|
|B−V color index||+1.03|
|Variable type||Classical Cepheid|
|Radial velocity (Rv)||+3.3 km/s|
|Proper motion (μ)||RA: –12.88 mas/yr
Dec.: +8.19 mas/yr
|Parallax (π)||2.09 ± 0.29 mas|
|Distance||approx. 1,600 ly
(approx. 480 pc)
|Mass||8.4 to 13 M☉|
|Surface gravity (log g)||1.5 cgs|
|Metallicity [Fe/H]||0.30 dex|
HD 84810, also known as l Carinae (l Car), is a star in the southern constellation of Carina. It has a mean apparent magnitude of +3.4, making it readily visible to the naked eye and one of the brighter members of Carina. Based upon parallax measurements, it is approximately 1,600 light-years (490 parsecs) from Earth.
From the characteristics of its spectrum, l Carinae has a stellar classification of G5 Iab/Ib. This indicates the star has reached a stage in its evolution where it has expanded to become a supergiant with 169 times the radius of the Sun. As this is a massive star with 8–13 times the mass of the Sun, it rapidly burns through its supply of nuclear fuel and has become a supergiant in roughly 33 million years, after spending 15–17 million years as a main sequence star.
l Carinae is classified as a Cepheid variable star and its brightness varies over an amplitude range of 0.725 in magnitude with a long period of 35.560 days. The radial velocity of the star likewise varies by 39 km/s during each pulsation cycle. It has a compact circumstellar envelope that can be discerned using interferometry. The envelope has been resolved at an infrared wavelength of 10μm, showing a radius of 10–100 AU at a mean temperature of 100 K. The material for this envelope was supplied by mass ejected from the central star.
- van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
- Madore, B. F. (June 1975), "Photoelectric UBV photometry of Cepheids in the Magellanic Clouds and in the southern Milky Way", Astrophysical Journal Supplement Series 29: 219–284, Bibcode:1975ApJS...29..219M, doi:10.1086/190342.
- Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (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, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x.
- Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". In Batten, Alan Henry; Heard, John Frederick. Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30. Determination of Radial Velocities and their Applications 30 (University of Toronto: International Astronomical Union). p. 57. Bibcode:1967IAUS...30...57E.
- Kervella, P.; Mérand, A.; Gallenne, A. (May 2009), "The circumstellar envelopes of the Cepheids ℓ Carinae and RS Puppis. Comparative study in the infrared with Spitzer, VLT/VISIR, and VLTI/MIDI", Astronomy and Astrophysics 498 (2): 425–443, arXiv:0902.1588, Bibcode:2009A&A...498..425K, doi:10.1051/0004-6361/200811307.
- Davis, J.; et al. (April 2009), "Observations of the pulsation of the Cepheid l Car with the Sydney University Stellar Interferometer", Monthly Notices of the Royal Astronomical Society 394 (3): 1620–1630, arXiv:0812.4791, Bibcode:2009MNRAS.394.1620D, doi:10.1111/j.1365-2966.2009.14433.x.
- Luck, R. E. (September 1979), "The chemical compositions of nine southern supergiant stars", Astrophysical Journal, Part 1 232: 797–806, Bibcode:1979ApJ...232..797L, doi:10.1086/157340.
- Klagyivik, P.; Szabados, L. (September 2009), "Observational studies of Cepheid amplitudes. I. Period-amplitude relationships for Galactic Cepheids and interrelation of amplitudes", Astronomy and Astrophysics 504 (3): 959–972, arXiv:0908.3561, Bibcode:2009A&A...504..959K, doi:10.1051/0004-6361/200811464.