HD 196885

HD 196885 is a binary star system in the northern constellation of Delphinus. It is near the lower limit of visibility to the naked eye with an apparent visual magnitude of 6.39.^[2] According to its parallax of 29.24 mas, it is located at a distance of 112 light years from the Sun. It is drifting closer with a radial velocity of −30 km/s, and is expected to come to within 52.5 light-years in 836,000 years.^[2] The absolute magnitude of the system is 3.76.^[2]

The primary, component A, is an F-type main-sequence star with a stellar classification of F8V^[3] It is about two billion years old and is spinning with a projected rotational velocity, for a rotation period of around 15 days. The star has 1.33^[6] times the mass of the Sun and 1.45 times the Sun's radius.^[1] The metallicity of this star – what astronomers term the abundance of elements with higher atomic number than helium – is nearly double that in the Sun. It is radiating 2.7 times the luminosity of the Sun from its photosphere at an effective temperature of 6,340 K.^[6]

In 2004, a planet was announced to be orbiting the star in a 386-day orbit.^[8] Follow-up work published in 2008 did not confirm the original candidate but instead found evidence of a planet in a 3.63 years.^[6] This object has a minimum estimated mass at least three times that of the planet Jupiter.^[5] Perturbation by the secondary star in this system may have driven the planet into a high inclination orbit.^[9]

The secondary, component B, is a red dwarf star separated by 0.6 arcseconds from the primary star that was discovered in 2006 with NaCo at VLT.^[10][4] derive the orbital elements of the pair give an orbital period of 72 years, a semimajor axis of 21 AU, and an eccentricity of 0.42.^[5] It has a class in the range M1V to M3V^[4] with 45% of the Sun's mass.^[5]

The star BD+10 4351B, located 192 arcseconds away from HD 196885 is located at the same distance and may be a physically bound companion star, in which case HD 196885 is a triple system.^[11] If it is bound, then the separation is at least 6,600 AU (the separation along the line-of-sight is unknown, so this value represents a lower limit on the true separation).^{[citation needed]}

See also[]

• Epsilon Reticuli
• GJ 3021

References[]

Coordinates: 20^h 39^m 51.8756^s, +11° 14′ 58.737″