HD 43197 b is an extrasolar planet which orbits the G-type

main sequence In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Her ...

or subgiant

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

HD 43197 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 ...

, located approximately 204

light year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s away in the

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 ...

Canis Major Canis Major is a constellation in the Southern Celestial Hemisphere, southern celestial hemisphere. In the second century, it was included in Ptolemy's 48 constellations, and is counted among the 88 modern constellations. Its name is Latin fo ...

. This planet has a minimum mass 55% that of Jupiter and takes 0.85 years to orbit the star at a semimajor axis of 0.882 AU. Its has a high eccentricity of 0.74, but its inclination is not known. This planet was detected by

HARPS The High Accuracy Radial Velocity Planet Searcher (HARPS) is a high-precision echelle planet-finding spectrograph installed in 2002 on the ESO's 3.6m telescope at La Silla Observatory in Chile. The first light was achieved in February 2003. H ...

on October 19, 2009, together with 29 other planets. In 2022, a second super-Jovian planet was discovered orbiting HD 43197 using a combination of

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 ...

and

astrometry Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, the Milky Way. His ...

. Assuming HD 43197 b shares the outer planet's orbital inclination, its true mass would be about . The planet HD 43197 b is named Equiano. The name was selected in the NameExoWorlds campaign by Nigeria, during the 100th anniversary of the

IAU The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach ...

. Olaudah Equiano was a writer and abolitionist from Ihiala, Nigeria who fought injustice and for the elimination of the slave trade.

References

Exoplanets discovered in 2010 Exoplanets detected by radial velocity Giant planets Canis Major Exoplanets with proper names {{extrasolar-planet-stub