The stellar classification of HD 73526 is G6 V, indicating this is a G-type main-sequence star that, like the Sun, is generating energy through corehydrogen fusion. Based on its properties, it may be starting to evolve off the main sequence. This star has slightly more mass than the Sun and a 53% greater radius. The abundance of iron in its atmosphere suggests the star's metallicity – what astronomers term the abundance of elements with higher atomic number than helium – is 70% greater than in the Sun. It is a much older star with an estimated age of nearly ten billion years, and is spinning slowly with a projected rotational velocity of 1.7 km/s. The star is radiating more than double the luminosity of the Sun from its photosphere at an effective temperature of 5,564 K.
Planetary system
On June 13 2002, a 2.1 MJ planet HD 73526 b was announced orbiting HD 73526 in an orbit just a little smaller than that of Venus' orbit around the Sun. This planet receives an insolation 3.65 times that of Earth or 1.89 times that of Venus. This was a single planet system until 2006 when a 2.3 MJ second planet HD 73526 c was discovered. These planets forms a 2:1 orbital resonance with planet b. In fact, they seem to be in a very deep resonance with very long timescale stability due to an ACR (Apsidal Corotation Resonance) the planets seem to satisfy. Although these are minimum masses as the inclinations of these planets are unknown, orbital stability analysis indicates that the orbital inclinations of both planets are likely to be near 90°, making the minimum masses very close to the true masses of the planets.
