HD 43197 b

{{Short description|Extrasolar planet in the constellation Canis Major}}

{{Infobox planet

| name = HD 43197 b / Equiano

| discoverer = Naef et al.

| discovery_site = La Silla Observatory

| discovered = October 19, 2009

| discovery_method = radial velocity (HARPS)

| orbit_ref =

| apsis = astron

| semimajor = {{val|0.882|0.035|0.039|ul=AU}}

| eccentricity = {{val|0.742|0.017|0.018}}

| period = {{val|308.9|2.3|2.8|ul=d}}

| time_periastron = {{val|2452535.102|17.503|14.898}}

| arg_peri = {{val|268.525|3.824|4.523|u=deg}}

| semi-amplitude = {{val|25.439|1.472|1.121|ul=m/s}}

| star = HD 43197

| physical_ref =

| mass = {{val|0.553|0.052|0.048|p=≥|ul=Jupiter mass}}

}}

HD 43197 b is an extrasolar planet which orbits the G-type main sequence or subgiant star HD 43197, located approximately 204 light years away in the constellation Canis Major. 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. It has a high eccentricity of 0.74, but its inclination is not known. This planet was detected by HARPS 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 and astrometry. Assuming HD 43197 b shares the outer planet's orbital inclination, its true mass would be about {{Jupiter mass|4|link=y}}.

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. Olaudah Equiano was a writer and abolitionist from Ihiala, Nigeria who fought injustice and for the elimination of the slave trade.{{Cite web|url=http://www.nameexoworlds.iau.org/final-results|title=Approved names|website=NameExoworlds|language=en|access-date=2020-01-02}}{{Cite web|url=https://www.iau.org/news/pressreleases/detail/iau1912/|title=International Astronomical Union {{!}} IAU|website=www.iau.org|access-date=2020-01-02}}