| Extrasolarplanet: | yes |
| HD 81040 b | |
| Image Scale: | 1.5 |
| Image Alt: | Radial velocity curve of HD 81040 b |
| Discoverer: | Sozzetti et al. |
| Discovery Site: | Observatoire de Haute-Provence in France |
| Discovered: | November 24, 2005 |
| Apsis: | astron |
| Semimajor: | 1.946± |
| Period: | 1004.7± |
| Semi-Amplitude: | 168 ± 9 |
HD 81040 b is a massive gas giant exoplanet that orbits the star HD 81040, discovered in 2005 by radial velocity. Its orbital period is just over 1000 days. It has a semimajor axis of about 1.95 AU, and its orbit is quite eccentric, at a little over 0.5.
Astrometry of HD 81040 using Gaia, published in several papers, has determined an orbital inclination of about 111°. This, combined with the minimum mass, gives a true mass of . Since the inclination is high, there is a small chance that the planet transits.