This is asolar analog, which is defined as a "Population Idwarf with gross properties not very different from those of the Sun".[13] It is aG-type main sequence star with astellar classification of G3 V,[4] which means it is generating energy through thefusion of hydrogen into helium at its core. The mass and radius of the star are similar to the Sun,[14] although the abundance of elements other than hydrogen and helium is about 50% greater.[7] It is much younger than the Sun, being an estimated 850 million years of age.[7] Theeffective temperature of thestellar atmosphere is around 5,807 K,[9] giving it the yellow-hued glow of a G-type star.[15]
In 1980, this was found to be avariable star with a periodicity of 7.655 days, and it was givenvariable star designation BE Ceti. This variation in luminosity was interpreted to be the result ofrotational modulation ofstar spot activity in thephotosphere,[10] and hence it is classified as aBY Draconis variable.[3] There is considerable variation in the strength of the surface activity—to the point where it has appeared inactive during some observation runs. The strength of the surfacemagnetic field was measured to be 450 G.[10] The spectrum of this star includeslines oftitanium oxide andcalcium hydride, which, for a star of this class, is further evidence of star spot activity. Star spots cover an estimated 3% of the surface.[16]
9 Ceti has been examined for evidence of a planetary companion or adebris disk, but as of 2015 none has been found.[17] The age of the star and its motion through space suggest that it is a member of theHyadesstellar kinematic group.[18]
^abcKholopov, P. N.; et al. (March 1985), "The 67th Name-List of Variable Stars",Information Bulletin on Variable Stars,2681: 1,Bibcode:1985IBVS.2681....1K.
^Weaver, Harold F. (October 1947), "The Visibility of Stars Without Optical Aid",Publications of the Astronomical Society of the Pacific,59 (350): 232,Bibcode:1947PASP...59..232W,doi:10.1086/125956.
^Campbell, B.; Cayrel, R. (August 1, 1984), "Spectroscopic evidence for starspots in the G dwarf HD 1835",Astrophysical Journal Letters,283:L17 –L20,Bibcode:1984ApJ...283L..17C,doi:10.1086/184323.
