HD 196885 is a

binary star A binary star is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separate stars, in wh ...

system in the northern

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Delphinus Delphinus (Pronounced or ) is a small constellation in the Northern Celestial Hemisphere, close to the celestial equator. Its name is the Latin version for the Greek word for dolphin (). It is one of the 48 constellations listed by the 2nd c ...

. It comprise a pair of stars HD 196885 A and HD 196885 B on a 69-years eccentric orbit. The primary star is near the lower limit of visibility to the naked eye with an

apparent visual magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's lig ...

of 6.39. It is located at a distance of 110.9 light years from the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

. It is drifting closer with a

radial velocity The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the temporal rate of change, rate of change of the distance or Slant range, range between the two points. It is e ...

of −30 km/s, and is expected to come to within in 836,000 years. The secondary, component B, is a

red dwarf ''Red Dwarf'' is a British science fiction comedy franchise created by Rob Grant and Doug Naylor, which primarily consists of a television sitcom that aired on BBC Two between 1988 and 1999, and on Dave since 2009, gaining a cult following. T ...

star separated by 0.6 arcseconds from the primary star that was discovered in 2006 with NaCo at VLT. It has a class in the range M1V to M3V with 51% of the Sun's mass. 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. 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).

Planetary system

In 2004, a

planet A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a you ...

was announced to be orbiting the star HD 196885 A in a 386-day orbit. Follow-up work published in 2008 did not confirm the original candidate but instead found evidence of a planet in a . Perturbation by the secondary star in this system may have driven the planet into a high

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object ...

orbit. The planetary existence was confirmed and parameters were refined by 2022.

References

{{DEFAULTSORT:HD 196885 F-type main-sequence stars M-type main-sequence stars Planetary systems with one confirmed planet Binary stars Delphinus BD+10 4351 196885 101966 7907 J20395188+1114588

Planetary system

See also

References