38 Arietis

38 Arietis (abbreviated 38 Ari) is a variable star in the northern constellation of Aries. 38 Arietis is the Flamsteed designation. It was once designated 88 Ceti,^[13] forming part of the neighboring constellation of Cetus. With an apparent visual magnitude of +5.18,^[4] it is bright enough to be viewed with the naked eye. The measured annual parallax shift of 27.52 mas^[3] is equivalent to a distance of approximately 119 light-years (36 parsecs) from Earth.

38 Arietis

Four visual band light curves for 38 Arietis, adapted from Valtier et al. (1974)[1]
Observation data Epoch J2000      Equinox J2000
Constellation	Aries[2]
Right ascension	02h 44m 57.57945s[3]
Declination	+12° 26′ 44.7297″[3]
Apparent magnitude (V)	+5.178[4]
Characteristics
Spectral type	A7 III-IV[5]
U−B color index	+0.121[4]
B−V color index	+0.235[4]
Variable type	δ Sct[6]
Astrometry
Radial velocity (Rv)	-1.5[7] km/s
Proper motion (μ)	RA: +120.49[3] mas/yr Dec.: -85.78[3] mas/yr
Parallax (π)	27.52±0.40 mas[3]
Distance	119 ± 2 ly (36.3 ± 0.5 pc)
Absolute magnitude (MV)	2.22[8]
Details
Radius	2.1[9] R☉
Luminosity	11[8] L☉
Surface gravity (log g)	4.04[8] cgs
Temperature	7,638[8] K
Rotational velocity (v sin i)	86[10] km/s
Age	0.58[11] Gyr
Other designations
UV Arietis, BD+11°377, HD 17093, HIP 12832, HR 812, SAO 93083[12]
Database references
SIMBAD	data

Rober L. Millis discovered that 38 Arietis is a variable star, at Lowell Observatory, in October 1966. The discovery was announced in 1967.^[14] It was given its variable star designation, UV Arietis, in 1970.^[15]

The spectrum of this star matches a stellar classification of A7 III-IV,^[5] with the luminosity class of III-IV indicating it shows traits part way between the subgiant and giant star stages of its evolution. It is a Delta Scuti variable with a period of 0.0355 days (51 minutes) and a magnitude change of 0.040.^[6] This star is larger than the Sun, with more than double the Sun's radius and 11 times the luminosity.^[8] This energy is being radiated into outer space from the atmosphere at an effective temperature of 7,638 K,^[8] giving it the white-hued glow of an A-type star.