UX Orionis

UX Orionis is a variable star in the constellation of Orion. It is a Herbig Ae star, located about 1000 light years from the Earth.^[8] At its brightest it is a magnitude 9.5 object, so it is too faint to be seen with the naked eye.^[3] UX Orionis is the prototype of the UX Orionis class of variable stars (often called "UXors"), which are young stellar objects that exhibit large (greater than 2.8 magnitude), irregular changes in visual band brightness.^[9][3] UX Orionis was discovered by Henrietta Swan Leavitt.^[3]

UX Orionis

A visual band light curve for UX Orionis, plotted from ASAS data[1]
Observation data Epoch J2000      Equinox J2000
Constellation	Orion
Right ascension	05h 04m 29.9879s[2]
Declination	−03° 47′ 14.2867″[2]
Apparent magnitude (V)	9.48 – 12.5[3]
Characteristics
Spectral type	A3ea[3]
Astrometry
Proper motion (μ)	RA: 1.056±0.028 mas/yr[2] Dec.: -3.998±0.019 mas/yr[2]
Parallax (π)	3.1004±0.0285 mas[2]
Distance	1,052 ± 10 ly (323 ± 3 pc)
Details
Mass	1.2[4] M☉
Radius	2.1[4] R☉
Luminosity	5.6[4] L☉
Surface gravity (log g)	3.86[4] cgs
Temperature	6,136[4] K
Rotational velocity (v sin i)	143[5] km/s
Age	4.8[6] Myr
Other designations
HD 293782, HIP 23602, GSC 04758-00134, 2MASS J05042998-0347142, Gaia DR3 3212878018378138752[7]
Database references
SIMBAD	data

UX Orionis is surrounded by a circumstellar disk, and the star's photometric variability appears to be caused by episodes during which the star is obscured by dusty material within the circumstellar disk.^[8]