Eta Sculptoris, Latinized from η Sculptoris, is a single, variable star in the central part of the southern

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

of Sculptor. It is visible to the naked eye as a faint, red-hued star with an apparent visual magnitude that fluctuates around 4.81. The star is located approximately 460 light years from the Sun based on

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby objects ...

, and is drifting further away with a

radial velocity The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the temporal rate of change, rate of change of the distance or Slant range, range between the two points. It is e ...

of +12 km/s. EtaSclLightCurve

This object is an aging

red giant A red giant is a luminous giant star of low or intermediate mass (roughly 0.3–8 solar masses ()) in a late phase of stellar evolution. The outer atmosphere is inflated and tenuous, making the radius large and the surface temperature around or ...

star, currently on the

asymptotic giant branch The asymptotic giant branch (AGB) is a region of the Hertzsprung–Russell diagram populated by evolved cool luminous stars. This is a period of stellar evolution undertaken by all low- to intermediate-mass stars (about 0.5 to 8 solar masses) lat ...

, with a

stellar classification In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grati ...

of M4III. With the supply of hydrogen at its core exhausted, the star has cooled and expanded. It now has 80 times the

radius of the Sun Solar radius is a unit of distance used to express the size of stars in astronomy relative to the Sun. The solar radius is usually defined as the radius to the layer in the Sun's photosphere where the optical depth equals 2/3: :1\,R_ = 6.957\t ...

. Eta Sculptoris is classified as a semiregular variable with a visual magnitude that fluctuates between +4.80 and +4.90, The pulsations have periods of 22.7, 23.5, 24.6, 47.3, 128.7 and 158.7 days. On average, this star is radiating over a thousand times the luminosity of the Sun from its enlarged

photosphere The photosphere is a star's outer shell from which light is radiated. The term itself is derived from Ancient Greek roots, φῶς, φωτός/''phos, photos'' meaning "light" and σφαῖρα/''sphaira'' meaning "sphere", in reference to it ...

at an

effective temperature The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature ...

of 3,641 K.

References

{{DEFAULTSORT:Eta Sculptoris M-type giants Asymptotic-giant-branch stars Semiregular variable stars Sculptor (constellation) Sculptoris, Eta CD-33 152 002429 002210 0105