HD 98618 is a yellow-hued star in the northern circumpolar constellation of Ursa Major. It is invisible to the naked eye, having an apparent visual magnitude of just 7.65.^[2] Based on measurements, this star is located at a distance of 135 light years from the Sun based on parallax,^[1] and is drifting further away with a radial velocity of +7.1 km/s.^[2] It is a likely member of the thin disk population and is orbiting the Milky Way at about the same distance from the Galactic Center as the Sun.^[6]

The stellar classification of HD 98618 is G5V,^[2] which matches an ordinary G-type main-sequence star that is generating energy through hydrogen fusion in the core region. It is almost identical in most respects to the Sun; it has therefore been proposed as a candidate solar twin.^[6] However, like the solar twin 18 Scorpii, HD 98618 has a lithium abundance significantly higher than that of the Sun ([Li/H] = +0.45 ± 0.08).^[7] Meléndez & Ramírez (2007) have suggested that HD 98618 be considered a "quasi solar twin", since they have now identified a solar twin, HIP 56948, with lithium content identical within the observational error to the Sun's.

The star appears roughly the same age as the Sun,^[6] although the level of chromospheric activity suggests it may be older.^[7] It is rotating with a leisurely projected rotational velocity of 2.1 km/s. The mass and size of the star are a few percent higher than the Sun. It is radiating around 10% more luminosity than the Sun from its photosphere at an effective temperature of 5,812 K.^[4]