Tags: Star.
HD 12039 is a variable star in the constellation of Cetus at a distance of about 133 ly (41 pc). It is categorized as a BY Draconis variable because of luminosity changes caused by surface magnetic activity coupled with rotation of the star. The stellar classification G4V is similar to our own Sun indicating this is a main sequence star that is generating energy at its core through the thermonuclear fusion of hydrogen. The effective temperature of 5585 K gives the star a yellow hue.