DN Orionis

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DN Orionis

A near-infrared (y band) light curve for DN Orionis. The main plot shows the variation over a full orbital period, and the inset plot shows the time near maximum eclipse. Adapted from Etzel and Olson (1995)[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Orion
Right ascension 06h 00m 28.34516s[2]
Declination 10° 13′ 04.9963″[2]
Apparent magnitude (V) 9.18[3]
Characteristics
Spectral type A0 + G5III[4]
B−V color index 0.240±0.026[3]
Distance
1,710 ± 40 ly
(520 ± 10 pc)
Absolute magnitude (MV)0.19 + 0.86[1]
Semi-amplitude
(K1)
(primary)
8.2 km/s
Semi-amplitude (K2)
(secondary)
120.4 km/s
Details
Primary
Mass2.80±0.05[1] M
Radius2.36±0.07[1] R
Luminosity50[1] L
Surface gravity (log g)4.14 cgs
Secondary
Mass0.34±0.10[1] M
Radius6.66±0.15[1] R
Luminosity25[1] L
Surface gravity (log g)2.31 cgs
HIP 28456, SAO 95108[6]
Database references
SIMBADdata

DN Orionis is an Algol variable[7] located in the constellation of Orion. The primary star is a spectral type A0 star and the secondary is an evolved giant star of type G5III.[4] The pair form a classical Algol-type system in which each star eclipses the other once per orbit, dropping the visual magnitude from 9.14 down to 9.62 at primary minimum and 9.25 at secondary minimum.[7] Their orbital period is close to 13 days long.[5]

This is a slightly

spectrum.[4] The pair have an unusually low mass ratio and the secondary appears to be of very low mass and overluminous.[5] Mass is flowing from the extended atmosphere of the cooler secondary to the hotter primary.[1] An evolutionary history of this system suggests that the current secondary was once the primary component, but has since transferred most of its mass to the partner star as it evolved off the main sequence.[4]

References