HD 98618 is a G-type main-sequence star located approximately 131 light-years (40 parsecs) from the Sun in the constellation Chamaeleon. It is slightly more massive and luminous than our Sun, with a spectral type of G1V. The star is known to host at least one exoplanet.
Characteristics
- Star Type: HD 98618 is a yellow dwarf star, classified as a G-type main-sequence star. Its spectral type, G1V, indicates it is similar to the Sun (G2V) but slightly hotter and brighter.
- Location: It is situated in the southern celestial hemisphere, within the constellation Chamaeleon.
- Distance: The star is approximately 131 light-years (40.2 parsecs) away from Earth.
- Apparent Magnitude: Its apparent visual magnitude is around 7.6, meaning it is too faint to be seen with the naked eye but can be observed with binoculars or a small telescope.
- Mass and Radius: HD 98618 has an estimated mass of about 1.05 times that of the Sun and a radius approximately 1.07 times the Sun's radius.
- Temperature: Its effective temperature is around 5,880 Kelvin, slightly higher than the Sun's.
- Luminosity: The star emits about 1.25 times the luminosity of the Sun.
- Age: The estimated age of HD 98618 is approximately 4.2 billion years, which is comparable to the Sun's age.
Planetary System HD 98618 is orbited by at least one confirmed exoplanet, designated HD 98618 b. This planet was discovered in 2011 using the radial velocity method, which detects the wobble in the star caused by the gravitational pull of an orbiting planet.
- HD 98618 b:
- Mass: It is classified as a "super-Earth" or "mini-Neptune" with a minimum mass of approximately 3.3 Earth masses.
- Orbital Period: The planet orbits its host star very closely, completing one revolution in just 3.7 days.
- Semi-major Axis: Its orbital distance is extremely small, about 0.046 AU (astronomical units), which is much closer than Mercury is to the Sun.
- Characteristics: Due to its close proximity to the star, HD 98618 b is expected to be very hot and would not be considered within the habitable zone.
Observational History The star was first cataloged in the Henry Draper Catalogue, an astronomical star catalogue published by the Harvard College Observatory from 1918 to 1924, which gave it its designation HD 98618. Its planetary companion, HD 98618 b, was announced in 2011 as part of a survey for exoplanets around Sun-like stars.