HD 45184 is a star in the southern constellation of Canis Major. It is a yellow-hued star near the lower limit of visibility to the naked eye with an apparent visual magnitude of 6.37.^[2] The star is located at a distance of 71.65 light years from the Sun based on parallax.^[1] It is drifting closer with a radial velocity of −3.8 km/s.^[1]

This object is an ordinary G-type main-sequence star with a stellar classification of G2Va,^[3] and it is considered a solar twin.^[5] The mass, size, and luminosity of the star are slightly higher than for the Sun, and it has a near solar metallicity – what astronomers term the abundance of elements with higher atomic numbers than helium. The star is around three billion years old and is spinning with a 20-day period.^[6] It has a 5.14^[9]-year magnetic activity cycle that has a lower amplitude than on the Sun.^[7]

HD 45184 has a planet around 12 times as massive as Earth that takes 5.88 days to complete an orbit around its host star. This planet was detected using the radial velocity method.^[10] It was later confirmed with Spitzer, whereupon a second candidate planet of similar mass was discovered orbiting with a 13.1 day period. The star was observed by Spitzer for a transit of the inner planet, but no event was detected.^[11] Both Neptune-like planets have near circular orbits close to the host star.^[7]

An infrared excess has been detected using the Multiband Imaging Photometer for Spitzer at a wavelength of 70 μm, making this a debris disk candidate.^[12] Based upon blackbody models, it is orbiting 1.0 AU from the host star with a mean temperature of 280 K. There may be an additional, 60 K debris disk orbiting at a distance of 22.89 AU.^[13]