HD 86226 is a star with a pair of orbiting exoplanet companions, found in the constellation of Hydra. With an apparent visual magnitude of 7.93, it is too dim to be visible with the naked eye. The distance to this system has been determined by the parallax method, yielding a range of 149light years. It is receding with a heliocentric radial velocity of +19.6km/s. A survey in 2015 has ruled out the existence of any stellar companions at projected distances above 12 astronomical units.

Description

This is an ordinary G-type main-sequence star with a stellar classification of G2V. It is similar in size, mass, and composition to the Sun, although it is not considered a solar twin. The age is about 3.8 billion years old. The star is radiating 18% greater luminosity (compared to the Sun) from its photosphere at an effective temperature of 5,863K. It is spinning with a projected rotational velocity of 3.6km/s.

As of 2014[update], Radio emission at a frequency of 150MHz has been tentatively detected from the proximity of this system, although it is not clear whether the star or a satellite orbiting a rapidly rotating planet is the source.

Planetary system

Due to the periodic spectrum shifts when it had when placed under a Doppler test, 13 Magellan Doppler Velocity observations were made of an object found near the star. The object discovered in 2010 had a Keplerian orbit, was declared an exoplanet and dubbed HD 86226 b. A hot Super-Earth planet called HD 86226 c was discovered in 2020. It may be undergoing considerable atmospheric mass loss.

The HD 86226 planetary system
Companion (in order from star)MassSemimajor axis (AU)Orbital period (days)EccentricityInclination (°)Radius
c7.25+1.19 −1.12M🜨0.049±0.0013.984436±0.0002170.06±0.0886.45+0.26 −0.162.16±0.08R🜨
b0.46±0.04MJ2.73±0.061,609.5±19.40.04±0.07——

See also

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