EQ Pegasi
Discovery
EQ Pegasi was first noticed to be a binary star by Carl A. Wirtanen who in the course of a systematic survey of the McCormick Observatory photographic plates for M-type dwarfs, detected a companion about two magnitudes fainter at a separation of 3.5 arcseconds.
Both components were also thought to be single-lined spectroscopic binaries, with faint companions that have not been resolved in orbits of a few years, but this is no longer thought to be the case. A 2021 study of nearby stars states that "the spectroscopic binarity classification [...] is almost certainly due to activity".
Planetary system
In 2022, a Jovian planet was discovered in orbit around the system's primary star via radio astrometry. Along with the planet around TVLM 513-46546, this is the first confirmed exoplanet discovered entirely using astrometry.
Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | 2.26±0.57 MJ | 0.64282±0.00068 | 284.39±1.47 | 0.35±0.19 | 69.20±25.61° | — |
In culture
In 1998, it was the basis of a hoax, as a telecommunications company claimed it had discovered "alien" signals originating from the star.
Gallery
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A visual band light curve for EQ Pegasi A, adapted from Norton et al. (2007)
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An ultraviolet band light curve for a flare on EQ Pegasi B, adapted from Mathioudakis et al. (2006)