variable star
A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as e ...
Sextans
Sextans is a minor equatorial constellation which was introduced in 1687 by Johannes Hevelius. Its name is Latin for the astronomical sextant, an instrument that Hevelius made frequent use of in his observations.
Notable features
Sextans as ...
. With an
apparent visual magnitude
Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's lig ...
of 5.07, it is faintly visible to the naked eye on a dark night. According to the Bortle scale, it can be viewed from brighter lit suburban skies. The distance to this star, based upon an annual parallax shift of 8.96 mas, is around 364 light years.
This star served as a primary standard in the
MK spectral classification
In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the ...
B-type main sequence star
A B-type main-sequence star (B V) is a main-sequence (hydrogen-burning) star of spectral type B and luminosity class V. These stars have from 2 to 16 times the mass of the Sun and surface temperatures between 10,000 and 30,000 K. B-type stars ...
. However, Houk and Swift (1999) list a classification of B5 IV/V, suggesting it may be transitioning into a
subgiant star
A subgiant is a star that is brighter than a normal main-sequence star of the same spectral class, but not as bright as giant stars. The term subgiant is applied both to a particular spectral luminosity class and to a stage in the evolution o ...
. It has served as a ''uvby'' photometric standard, but is also categorized as an Alpha2 Canum Venaticorum variable with a suspected period of 15.4 days. This lengthy a period conflicts with a relatively high
projected rotational velocity
Stellar rotation is the angular motion of a star about its axis. The rate of rotation can be measured from the spectrum of the star, or by timing the movements of active features on the surface.
The rotation of a star produces an equatorial bulg ...
of 85 km/s, leaving the explanation for the variance unresolved.