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HD 84810

ℓ Carinae
Carina constellation map.svg
Red circle.svg

Location of l Carinae (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Carina
Right ascension 09h 45m 14.81122s
Declination –62° 30′ 28.4519″
Apparent magnitude (V) 3.39(3.35 - 4.06)
Characteristics
Spectral type F6Ib-K0Ib
U−B color index +0.76
B−V color index +1.03
Variable type Classical Cepheid
Astrometry
Radial velocity (Rv) +3.3 km/s
Proper motion (μ) RA: –12.88 mas/yr
Dec.: +8.19 mas/yr
Parallax (π) 2.09 ± 0.29mas
Distance 525pc
Absolute magnitude (MV) –5.22
Details
Mass 8.4 to 13 M
Radius 169±8 R
Surface gravity (log g) 1.5 cgs
Temperature 5,091 K
Metallicity [Fe/H] 0.30 dex
Age 17-19 Myr
Other designations
l Carinae, 2MASS J09451481-6230284, CD–61 2349, FK5 1254, HD 84810, HIP 47854, HR 3884, IRAS 09438-6216, SAO 250683.
Database references
SIMBAD data

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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