HATS-11b

Lore & Background

HATS-11b was discovered in 2016 using the primary transit method by the Hungarian Automated Telescope Network (HATNet) as part of the HATSouth survey, which aims to discover exoplanets via transits. Its mass was determined using the radial velocity method. The planet has an orbital period of about 3.6 Earth days and a calculated temperature of 1637 K. Its mass is 0.85 Jupiter masses and its radius is 1.49 Jupiter radii, with an orbital eccentricity of less than 0.34, indicating an elliptical orbit.

The host star, HATS-11, is a G0 type star with a solar mass of 1 and a solar radius of 1.44. It has an effective temperature of about 6060 K and is roughly 7.7 billion years old. The star is notably metal-poor, with a metallicity of about -3.09 [Fe/H], meaning it has roughly one-thousandth the abundance of iron relative to the Sun. Its apparent magnitude is 14, making it invisible to the naked eye.

HATS-11b is described as similar to Jupiter, but its close orbit and high temperature distinguish it from the gas giants in the Solar System. The planet's low-metallicity host star adds to its scientific interest, as such systems are less common among known exoplanets.

Reader's Guide

HATS-11b is notable as a confirmed exoplanet discovered in 2016 by the HATSouth survey, part of the HATNet project. Its discovery via the primary transit method and subsequent mass measurement via radial velocity contributed to the growing catalog of exoplanets found by these techniques. As of February 10, 2020, the HATSouth project had discovered 61 exoplanets since its start in 2009, placing HATS-11b within a systematic survey effort. The planet's characteristics—a mass of 0.85 Jupiter masses, radius of 1.49 Jupiter radii, and an orbital period of 3.6 days—illustrate the diversity of hot Jupiters. Its host star, HATS-11, is a G0 star with extremely low metallicity (about -3.09 [Fe/H]), roughly one-thousandth the iron abundance of the Sun. This makes the system a valuable case study for planet formation in metal-poor environments, challenging models that require high metallicity for giant planet formation. The planet's high temperature of 1637 K and elliptical orbit (eccentricity less than 0.34) further add to its interest. HATS-11b's legacy lies in its role as a benchmark for understanding how gas giants can form and evolve around ancient, metal-poor stars, and it remains a target for follow-up studies of atmospheric and orbital properties.

Did You Know?

• HATS-11b is also known as EPIC 216414930b.
• The planet's temperature is calculated to be 1637 K.
• HATS-11b was discovered using the primary transit method in 2016.