Epoch J2000.0 Equinox J2000.0
|Right ascension||09h 45m 14.81122s|
|Declination||–62° 30′ 28.4519″|
|Apparent magnitude (V)||3.39 (3.35 - 4.06)|
|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|
|Absolute magnitude (MV)||–5.22|
|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 17-19 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.
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