HATS-49 b
Astrophysical Synthesis & Habitability Characterization
HATS-49 b is a confirmed gas giant exoplanet orbiting the star HATS-49, located approximately 1058.1 light-years (324.41 parsecs) from the Solar System. First announced in 2020 by HATSouth using the Transit detection technique (producing an estimated primary transit depth of 1.2696% across the stellar disk), this world measures 8.575 Earth radii (0.77 Jupiter radii) and has a measured mass of 112.194 Earth masses (0.35 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.98 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.53 g⊕ (15 m/s²), and an escape velocity of 40.5 km/s.
In its orbital architecture around HATS-49, HATS-49 b completes one full revolution every 4.148 Earth days at a semi-major axis of 0.04515 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 118.4 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.071 carries the world between 0.0419 AU at periapsis and 0.0484 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 835 K (+562°C / +1044°F) and receiving 80.45 S⊕ (~109,492 W/m²), HATS-49 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HATS-49 is classified as a stellar host with an effective photospheric temperature of 4,405 K, a radius of 0.6977 R☉, a mass of 0.7133 M☉, an estimated bolometric luminosity of 0.164 L☉. Stellar evolution modeling indicates an estimated stellar age of 10.5 Gyr and a metallicity of [Fe/H] = 0.208 dex (metal-rich relative to the Sun). From Earth, HATS-49 shines at apparent V-band magnitude 14.988 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere.
Methodology: Computed using the Schulze-Makuch et al. (2011) weighted metric comparing physical interior (radius, estimated density) and surface thermal regime (escape velocity, equilibrium temperature).
Discovery Facility: HATSouth · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HATS-49 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,405 K |
| Stellar Radius | 0.6977 R☉ |
| Stellar Mass | 0.7133 M☉ |
| Bolometric Luminosity | 0.164 L☉ |
| Metallicity [Fe/H] | 0.208 dex |
| Stellar Age | 10.500 Gyr |
| Apparent Magnitude | V: 14.988 · G: 14.545 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.045150 AU |
| Orbital Period | 4.148 days |
| Mean Orbital Velocity | 118.4 km/s |
| Orbital Eccentricity (e) | 0.07100 |
| Orbital Inclination (i) | 88.2700° |
| Mean Bulk Density | 0.98 g/cm³ (40.5 km/s vesc) |
| Insolation Flux | 80.4500 S⊕ (~109,492 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1058.100 LY (324.413 pc) |