TOI-5300 b
Astrophysical Synthesis & Habitability Characterization
TOI-5300 b is a confirmed gas giant exoplanet orbiting the star TOI-5300, located approximately 530 light-years (162.51 parsecs) from the Solar System. First announced in 2025 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 1.9356% across the stellar disk), this world measures 9.864 Earth radii (0.88 Jupiter radii) and has a measured mass of 190.697 Earth masses (0.6 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.1 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.96 g⊕ (19.22 m/s²), and an escape velocity of 49.2 km/s.
In its orbital architecture around TOI-5300, TOI-5300 b completes one full revolution every 2.262 Earth days at a semi-major axis of 0.0295 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 141.9 km/s (compared to Earth's 29.8 km/s). The orbit is modeled as circular (e = 0.00), maintaining a constant stellar distance throughout its year.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1043 K (+770°C / +1418°F) and receiving 198.00 S⊕ (~269,478 W/m²), TOI-5300 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-5300 is classified as an orange K-type star of spectral type K4 V with an effective photospheric temperature of 4,610 K, a radius of 0.65 R☉, a mass of 0.67 M☉, an estimated bolometric luminosity of 0.171 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.17 dex (metal-poor relative to the Sun). From Earth, TOI-5300 shines at apparent V-band magnitude 13.869 (faint and requiring research-grade or CCD telescopic photometry) in the Northern 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: Transiting Exoplanet Survey Satellite (TESS) · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | TOI-5300 |
| Spectral Type | K4 V |
| Effective Temp (Teff) | 4,610 K |
| Stellar Radius | 0.6500 R☉ |
| Stellar Mass | 0.6700 M☉ |
| Bolometric Luminosity | 0.171 L☉ |
| Metallicity [Fe/H] | -0.170 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 13.869 · G: 13.233 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.029500 AU |
| Orbital Period | 2.262 days |
| Mean Orbital Velocity | 141.9 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.2000° |
| Mean Bulk Density | 1.1 g/cm³ (49.2 km/s vesc) |
| Insolation Flux | 198.0000 S⊕ (~269,478 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 530.000 LY (162.510 pc) |