HD 66428 is a G-type main sequence star located approximately 174 light-years away in the constellation of Monoceros. This star is similar to the Sun with an apparent magnitude of 8.25, an effective temperature of 5705 ± 27 K and a solar luminosity 1.28. Its absolute magnitude is 11.1 while its U-V color index is 0.71. It is considered an inactive star and it is metal-rich ([Fe/H] = 0.310). [2] [3] [5] This star has a precise mass of 1.14552 solar masses. This precision comes from the Corot mission that measured asteroseismology.
In July 2006, the discovery of the extrasolar planet HD 66428 b was published in the Astrophysical Journal. It was found from observations at the W. M. Keck Observatory using the radial velocity method. It has a minimum mass of more than 3 times that of Jupiter and orbits at a distance of 3.47 AU away from the star. [2] [6]
In 2015 a refined orbit was determined which led to the discovery of a linear trend in the radial velocities indicating a more distant companion of unknown character, [6] which was determined to be a gas giant planet HD 66428 c or brown dwarf in 2021. [7] In 2022, the inclination and true mass of both planets were measured via astrometry. The orbital period and mass of planet c were found to be significantly lower than the previous higher-error estimates, showing it to be planetary mass and not a brown dwarf. [8]
Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (years) | Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | 10.946+2.442 −3.845 MJ | 3.395+0.141 −0.157 | 6.214+0.015 −0.016 | 0.471±0.012 | 16.639+10.121 −2.959 ° | — |
c | 1.764+3.404 −0.041 MJ | 9.408+1.945 −1.267 | 28.690+9.206 −5.348 | 0.207+0.097 −0.098 | 93.938+57.003 −55.476 ° | — |
HD 168443 is an ordinary yellow-hued star in the Serpens Cauda segment of the equatorial constellation of Serpens. It is known to have two substellar companions. With an apparent visual magnitude of 6.92, the star lies just below the nominal lower brightness limit of visibility to the normal human eye. This system is located at a distance of 127 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −48.7 km/s.
HD 169830 is a star in the southern constellation of Sagittarius. It has a yellow-white hue and is dimly visible to the naked eye with an apparent visual magnitude of +5.90. The star is located at a distance of 120 light years from the Sun based on parallax. It is drifting closer with a radial velocity of −17.3 km/s, and is predicted to come as close as 20.7 ly (6.4 pc) in 2.08 million years. HD 169830 is known to be orbited by two large Jupiter-like exoplanets.
HD 114783 is a star with two exoplanetary companions in the equatorial constellation of Virgo. With an apparent visual magnitude of 7.56 it is too faint to be visible with the unaided eye, but is an easy target for binoculars. Based on parallax measurements, it is located at a distance of 68.6 light-years from the Sun, but is drifting closer with a radial velocity of −12 km/s.
HD 28185 is a yellow dwarf star similar to the Sun located 128 light-years away from Earth in the constellation Eridanus. The designation HD 28185 refers to its entry in the Henry Draper catalogue. The star is known to possess one long-period extrasolar planet.
HD 38529 is a binary star approximately 138 light-years away in the constellation of Orion.
HD 1237 is a binary star system approximately 57 light-years away in the constellation of Hydrus.
HD 125612 is a binary star system with three exoplanetary companions in the equatorial constellation of Virgo. It is too dim to be visible to the naked eye, having an apparent visual magnitude of 8.31. The system is located at a distance of 188 light years from the Sun based on parallax measurements, but it is drifting closer with a radial velocity of −18 km/s.
HD 154345 is a star in the northern constellation of Hercules. With an apparent visual magnitude of +6.76 it is a challenge to view with the naked eye, but using binoculars it is an easy target. The distance to this star is 59.6 light years based on parallax, but it is drifting closer with a radial velocity of −47 km/s. At least one exoplanet is orbiting this star.
HD 219828 is a star with two exoplanetary companions in the constellation of Pegasus. With an apparent visual magnitude of 8.04, it is an eighth magnitude star that is too dim to be readily visible to the naked eye. The star is located at a distance of approximately 237 light years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −24 km/s.
HD 4113 is a dual star system in the southern constellation of Sculptor. It is too faint to be viewed with the naked eye, having an apparent visual magnitude of 7.88. The distance to this star, as estimated by parallax measurements, is 137 light years. It is receding away from the Sun with a radial velocity of +5 km/s.
HD 72659 is a star in the equatorial constellation of Hydra. With an apparent visual magnitude of 7.46, his yellow-hued star is too faint to be viewed with the naked eye. Parallax measurements provide a distance estimate of 169.4 light years from the Sun, and it has an absolute magnitude of 3.98. The star is drifting closer with a radial velocity of −18.3 km/s.
HD 117207 is a star in the southern constellation Centaurus. With an apparent visual magnitude of 7.24, it is too dim to be visible to the naked eye but can be seen with a small telescope. Based upon parallax measurements, it is located at a distance of 105.4 light-years from the Sun. The star is drifting closer with a radial velocity of −17.4 km/s. It has an absolute magnitude of 4.67.
HD 24040 is a metal-rich G-type star located approximately 152 light-years away in the constellation of Taurus. In 2006 a long-period planet was discovered.
HD 204313 is a star with two and possibly three exoplanetary companions in the southern constellation of Capricornus. With an apparent magnitude of 7.99, it is an eighth magnitude star that is too faint to be readily visible to the naked eye. The star is located at a distance of 157 light years from the Sun based on parallax measurements, but it is drifting closer with a radial velocity of −10 km/s.
HD 43197 is a star with an exoplanetary companion in the southern constellation of Canis Major. It has been given the proper name Amadioha, as selected by Nigeria during the NameExoWorlds campaign that celebrated the 100th anniversary of the IAU. Amadioha is the god of thunder in Igbo mythology. It has an apparent visual magnitude of 8.98, meaning this is a ninth magnitude star that is too dim to be visible to the naked eye. The system is located at a distance of 204 light-years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of +72 km/s. It made its closest approach some 583,000 years ago when it came to within 87 light-years.
HD 126614 is a trinary star system in the equatorial constellation of Virgo. The primary member, designated component A, is host to an exoplanetary companion. With an apparent visual magnitude of 8.81, it is too faint to be seen with the naked eye. The system is located at a distance of 239 light years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −33 km/s.
HD 164604 is a single star in the southern constellation of Sagittarius constellation. It has the proper name Pincoya, as selected in the NameExoWorlds campaign by Chile, during the 100th anniversary of the IAU. Pincoya is a female water spirit from southern Chilean mythology who is said to bring drowned sailors to the Caleuche so that they can live in the afterlife. A 2015 survey ruled out the existence of any additional stellar companions at projected distances from 13 to 340 astronomical units. It is known to host a single super-Jupiter exoplanet.
HD 175167 is a star with an exoplanet companion in the southern constellation of Pavo. It is too faint to be visible with the naked eye at an apparent visual magnitude of 8.01. The system is located at a distance of 232 light-years from the Sun based on parallax measurements, and it is drifting further away with a radial velocity of 5 km/s. It shows a high proper motion, traversing the celestial sphere at an angular rate of 0.190 arcsec yr−1.
HD 175167 b is an exoplanet orbiting HD 175167, which is a G type star within the Pavo constellation 232 light-years away from the Earth. The planet was discovered by the Magellan Planet Search Program as the astronomical object fit the Keplerian orbital model. During the observations 13 doppler velocity tests were conducted, which showed this object's mass was at least 7.8 Jovian-masses and its orbit has a high eccentricity. The exoplanet takes 3.53 years to complete a full stellar orbit.
HD 106515 is a binary star in the constellation of Virgo.