38 Arietis
A Delta Scuti variable in Aries, discovered in 1966.
38 Arietis, also cataloged as UV Arietis, is a variable star located in the northern constellation Aries. Its Flamsteed designation is 38 Arietis, and it was once known as 88 Ceti, belonging to the adjacent constellation Cetus. With an apparent visual magnitude of roughly +5.2, it can be seen without a telescope. Based on a measured annual parallax shift of 27.52 milliarcseconds, its distance from Earth is about 119 light-years.
The star's variability was discovered by Robert L. Millis at Lowell Observatory in October 1966, with the finding announced the following year. It received its variable star designation, UV Arietis, in 1970. Its spectrum corresponds to a stellar classification of A7 III–IV, meaning its luminosity class falls between a subgiant and a giant. It is a Delta Scuti variable, pulsating with a period of 0.0355 days (about 51 minutes) and exhibiting a magnitude change of 0.040.
38 Arietis is larger than the Sun, possessing more than double the Sun's radius and 11 times its luminosity. This energy radiates from its atmosphere at an effective temperature of 7,638 K, giving it the white hue characteristic of an A-type star.
- Flamsteed designation
- 38 Arietis
- Variable star designation
- UV Arietis
- Apparent visual magnitude
- +5.2
- Distance
- approximately 119 ly
- Spectral type
- A7 III-IV
- Variable type
- Delta Scuti
- Period
- 0.0355 days (51 minutes)
Lore & Background
Robert L. Millis discovered that 38 Arietis is a variable star at Lowell Observatory in October 1966, with the discovery announced in 1967. It received its variable star designation, UV Arietis, in 1970. The spectrum of this star matches a stellar classification of A7 III-IV, 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. The measured annual parallax shift of 27.52 mas is equivalent to a distance of approximately 119 ly from Earth. This star is larger than the Sun, with more than double the Sun's radius and 11 times the luminosity. This energy is being radiated into outer space from the atmosphere at an effective temperature of 7,638 K, giving it the white-hued glow of an A-type star.
Reader's Guide
38 Arietis holds significance as a Delta Scuti variable star, a class of pulsating stars important for studying stellar structure and evolution. Its discovery by Robert L. Millis at Lowell Observatory in 1966 added to the catalog of known variable stars, and its variable star designation UV Arietis was assigned in 1970. The star's spectral classification of A7 III-IV places it in a transitional evolutionary stage between subgiant and giant, offering insight into stellar aging processes. With a short period of 51 minutes and a small magnitude change of 0.040, it exemplifies the rapid, low-amplitude pulsations characteristic of Delta Scuti variables. Its brightness at magnitude +5.2 makes it accessible to amateur astronomers with good viewing conditions. The star's former designation as 88 Ceti reflects historical boundary changes between constellations. Its physical parameters—more than double the Sun's radius, 11 times its luminosity, and an effective temperature of 7,638 K—provide a concrete example of an A-type star in a specific evolutionary phase. The parallax-derived distance of about 119 ly anchors its place in the local stellar neighborhood.
Did You Know?
- 38 Arietis was once designated 88 Ceti, part of the neighboring constellation Cetus.
- It has a variable star designation of UV Arietis, assigned in 1970.
- The star's period is 0.0355 days, equivalent to 51 minutes.
- Its effective temperature is 7,638 K, giving it a white-hued glow.
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