Theta Persei 2

Star A is a main sequence dwarf star of spectral and luminosity type F7-8 V (Wittenmyer et al, 2006, page 178; Bonavita and Desidera, 2007, HD 16895 in Table 8; and NASA Stars and Exoplanet Database) but has been classed as yellow as F9 (Baize and Petit, 1989, page 505. The star may have around 1 to 1.4 times Sol's mass (Wittenmyer et al, 2006, page 178; Valenti and Fischer, 2005; Allende Prieto et al, 1999, page 30, Table 1 for HR 799; Bonavita and Desidera, 2007, HD 16895 in Table 8; and NASA Stars and Exoplanet Database; and David F. Gray, 1992), around 1.24 times Sol's diameter based on a power-law estimate (NASA Stars and Exoplanet database; and Kenneth R. Lang, 1980); and around 2.2 times its theoretical bolometric luminosity (NASA Stars and Exoplanet database; and Kenneth R. Lang, 1980). Depending the method used, it's age has been estimated in a wide range from around 1.2 to 7.9 billion years old (Beichman et al, 2006; Valenti and Fischer, 2005; Nordstrom et al, 2004; and Edvardsson et al, 1993, page 122 for HR 799). The star may only be around 0.71 to 1.2 times as enriched as Sol with elements heavier than hydrogen ("metallicity") based on its abundance of iron (Yoichi Takeda, 2007; Luck and Heiter, 2006, page 3075, Table 3; Allende Prieto et al, 1999, page 30, Table 1 for HR 799; and Cayrel de Strobel et al, 1991, page 280). It has a rotational period of around seven days (Cumming et al, 1999, page 892, Table 2 as HR 799). Star A has been designated NSV 902 as a New Suspected Variable star. Useful star catalogue numbers for the star include: The Per A, Tet Per A, 13 Per, HR 799, Gl 107 A, HIP 12777, HD 16895, BD+48 746 A, SAO 38288, FK 93, LTT 10894, Struve 296, and ADS 2081 A.

According to the Sixth Catalog of Orbits of Visual Binaries, Stars A and B move around each other at an average distance of 250 AUs (semi-major axis a=22.289") in a mildly eccentric (e= 0.13) orbit that takes 2,720 years to complete. Their orbit around each other is inclined by 75.44° with respect to an observer on Earth (Bonavita and Desidera, 2007, HD 16895 in Table 8; Proveda et al, 1994; Duquennoy and Mayor, 1991, page 504 for HD 16895; Worley and Heintz, 1983; and Josef Hopmann, 1958, pp. 77-180). The binary star system also has an optical companion (Duquennoy and Mayor, 1991, page 504 for HD 16895). (See an animation of the orbits of Stars A and B and their potentially habitable zones, with a table of basic orbital and physical characteristics.)

Star b is a main sequence dwarf star of spectral and luminosity type M1-2 Ve Duquennoy and Mayor, 1991, page 489 for Gl 107 B). It has 43 percent of Sol's mass (Bonavita and Desidera, 2007, HD 16895 in Table 8; and Worley and Heintz, 1983), a smaller diameter, and only around one percent of its visual luminosity. Useful star catalogue numbers for the star include: The Per B, Tet Per B, and Gl 107 B.

No Jupiter-class planets within 3 AUs were detected dusing radial-velocity variations by 2006 (Wittenmyer et al, 2006, page 186, Table 5; (Cumming et al, 1999; Abt and Levy, 1976, page 286, Table 2 for HR 799).