Iota Pegasi 2

Star A is a main sequence dwarf star of spectral and luminosity type F5 V (NASA Stars and Exoplanet Database). The star may have around 1.25 to 1.33 times Sol's mass (Jancart et al, 2005, page 14 under HIP 109176; Nordström et al, 2004; Boden et al, 1999; NASA Stars and Exoplanet Database; and David F. Gray, 1992; and Fekel and Tomkin, 1983), around 1.4 to 1.5 times Sol's diameter based on a power-law estimate (van Belle and von Braun, 2009, page 7, Table 4; NASA Stars and Exoplanet database; and Kenneth R. Lang, 1980); and around 3.3 times its theoretical bolometric luminosity (NASA Stars and Exoplanet database; and Kenneth R. Lang, 1980). Based on the stars' lithium abundance, their probable spectral type, and close-orbiting nature, they may be 80 to 600 million years old (Fekel and Tomkin, 1983; and Edvardsson et al, 1993, page 122 for HR 799), but some believe the system to be 2.5 billion years old (Nordström et al, 2004). The star may only be around 0.79 to 1.26 times as enriched as Sol with elements heavier than hydrogen ("metallicity") based on its abundance of iron (Nordström et al, 2004; and Cayrel de Strobel et al, 1991, page 310). Star A has been designated NSV 14034 as a New Suspected Variable star. Useful star catalogue numbers for the star include: Iot Peg A, 24 Peg, HR 8430, Gl 848 A, HIP 109176, HD 210027, BD+24 4533 A, SAO 90238, FK5 831, and LTT 16472.

According to the Ninth Catalogue of Spectroscopic Binary Orbits (for HD 210027), Stars A and B move around each other at an average distance of only 0.051 AUs (semi-major axis a=0.00407 +/- 0.27") in a highly circular (e~0) orbit that takes just 10.2 days to complete. Their orbit around each other is inclined by 80 +/-13° with respect to an observer on Earth (Tokovinin et al, 2006; Jancart et al, 2005, pp. 9-14; Boden et al, 1999; Fekel and Tomkin, 1983; Abt and Levy, 1976; Petrie and Phibbs, 1949; and Heber D. Curtis, 1904). (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.)

NASA



Iota Pegasi B is a yellow-orange star that is
somewhat cooler, dimmer, and less massive than
our Sun, Sol. (See Sloan Digital Sky Survey field
images of Iota Pegasi AB from WikiSky.org.)

Star b is a main sequence dwarf star of spectral and luminosity type G8 V (Fekel and Tomkin, 1983). It has 80 to 82 percent of Sol's mass (Jancart et al, 2005, page 14 under HIP 109176; Boden et al, 1999; and Fekel and Tomkin, 1983), smaller than Solar diameter, and less than Solar luminosity. Useful star catalogue numbers for this star include: Iot Peg B, HD 210027 B, BD+24 4533 B, CSI+24 4533 2, CCDM J22070+2520 A, and IDS 22023+2452 A.