HD 33519

HD 33519, also known as HR 1682, is a probable spectroscopic binary^[11] located in the southern circumpolar constellation Mensa. It is one of the stars near the limit of naked eye visibility, having an apparent magnitude of 6.28.^[2] The system is relatively far at a distance of 940 light years^[1] but is approaching with a heliocentric radial velocity of −2.5 km/s.^[5] However, this value is poorly constrained.

HD 33519

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Mensa
Right ascension	05h 00m 13.23704s[1]
Declination	−78° 18′ 00.0987″[1]
Apparent magnitude (V)	6.28±0.01[2]
Characteristics
Evolutionary stage	red giant branch[1]
Spectral type	K5/M0 III[3]
U−B color index	+1.87[4]
B−V color index	+1.51[4]
Astrometry
Radial velocity (Rv)	−2.5±2.3[5] km/s
Proper motion (μ)	RA: −17.781 mas/yr[1] Dec.: +1.497 mas/yr[1]
Parallax (π)	3.4534±0.0872 mas[1]
Distance	940 ± 20 ly (290 ± 7 pc)
Absolute magnitude (MV)	−0.88[6]
Details
Mass	4.34[7] M☉
Radius	45.4[8] R☉
Luminosity	465[9] L☉
Surface gravity (log g)	1.45+0.02 −0.03[1] cgs
Temperature	4,118±122[8] K
Metallicity [Fe/H]	−0.01[10] dex
Rotational velocity (v sin i)	<1[11] km/s
Other designations
19 G. Mensae[12], CD−78°190, CPD−78°165, HD 33519, HIP 23251, HR 1682, SAO 256153, WDS J05002-7818A[13]
Database references
SIMBAD	data

The visible component has a stellar classification of K5/M0 III,^[3] indicating an evolved red giant with the characteristics of a K5 and M0 giant star. At present it has 4.34 times the mass of the Sun^[7] but has expanded to 45.4 times its girth.^[8] It shines with a luminosity of 465 L_☉^[9] from its enlarged photosphere at an effective temperature of 4,118 K,^[8] giving it an orange-red hue when viewed in the night sky. HD 33519's metallicity, what astronomers dub as elements heavier than helium, is around solar level.^[10] Like most giants, it spins slowly, with its projected rotational velocity being lower than 1 km/s.^[11]

There is an 11th magnitude optical companion located 50.2″ away along a position angle of 110°.^[14] It has no relation to the system, having a drastically different proper motion.^[14]