IU Aurigae

A visual band light curve for IU Aurigae, adapted from Özdemir et al. (2003)[1]
Observation data Epoch J2000      Equinox J2000
Constellation	Auriga
Right ascension	05h 27m 52.40539s[2]
Declination	+34° 46′ 58.3435″[2]
Apparent magnitude (V)	8.19 to 8.83[3]
Characteristics
Spectral type	B0p + B1Vp[3] + ?
U−B color index	−0.66
B−V color index	+0.18
Variable type	Eclipsing binary[4]
Astrometry
Radial velocity (Rv)	9±5 km/s
Proper motion (μ)	RA: −4.479[2] mas/yr Dec.: −9.049[2] mas/yr
Parallax (π)	0.4786±0.5765 mas[2]
Distance	6,500 ly (2,000 pc)[1]
Details[1]
A
Mass	21.4±2.5 M☉
Radius	7.8±0.8 R☉
Luminosity	57,500 L☉
Surface gravity (log g)	3.99±0.17 cgs
Temperature	32,000 K
B
Mass	14.5±2.0 M☉
Radius	7.1±0.8 R☉
Luminosity	26,300 L☉
Surface gravity (log g)	3.89±0.19 cgs
Temperature	27,540±290 K
Other designations
IU Aur, BD+34°1051, HD 35652, HIP 25565, SAO 58059, PPM 70395[5]
Database references
SIMBAD	data

IU Aurigae is a triple star^[6] system in the constellation Auriga, consisting of an eclipsing binary pair orbiting a third component with a period of 335 years.^[7] This system is too faint to be viewed with the naked eye, having a peak apparent visual magnitude of 8.19.^[3]

Pavel Mayer discovered that the star's brightness varies in 1964.^[8] The eclipsing pair form a Beta Lyrae-type semidetached binary of two Bp stars^[3] with a period of 1.81147435 days.^[4] During the primary eclipse, the visual magnitude of the system drops to 8.89, while for the secondary it decreases to 8.74.^[3][9] The third component is a massive object with 17–18 M_☉, and may actually be a binary – which would make this a quadruple star system.^[7]

References