TOI-1298 b
Astrophysical Synthesis & Habitability Characterization
TOI-1298 b is a confirmed gas giant exoplanet orbiting the star TOI-1298, located approximately 1040.6 light-years (319.04 parsecs) from the Solar System. First announced in 2021 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.371% across the stellar disk), this world measures 9.658 Earth radii (0.86 Jupiter radii) and has a measured mass of 99 Earth masses (0.31 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.61 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.06 g⊕ (10.4 m/s²), and an escape velocity of 35.8 km/s.
In its orbital architecture around TOI-1298, TOI-1298 b completes one full revolution every 4.537 Earth days at a semi-major axis of 0.057 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 136.7 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 1278 K (+1005°C / +1841°F) and receiving 732.01 S⊕ (~996,262 W/m²), TOI-1298 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-1298 is classified as a stellar host with an effective photospheric temperature of 5,752 K, a radius of 1.4536 R☉, a mass of 1.2187 M☉, an estimated bolometric luminosity of 2.075 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.3 Gyr and a metallicity of [Fe/H] = 0.397 dex (metal-rich relative to the Sun). From Earth, TOI-1298 shines at apparent V-band magnitude 11.889 (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-1298 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,752 K |
| Stellar Radius | 1.4536 R☉ |
| Stellar Mass | 1.2187 M☉ |
| Bolometric Luminosity | 2.075 L☉ |
| Metallicity [Fe/H] | 0.397 dex |
| Stellar Age | 4.300 Gyr |
| Apparent Magnitude | V: 11.889 · G: 11.404 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.057000 AU |
| Orbital Period | 4.537 days |
| Mean Orbital Velocity | 136.7 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.9600° |
| Mean Bulk Density | 0.61 g/cm³ (35.8 km/s vesc) |
| Insolation Flux | 732.0077 S⊕ (~996,262 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1040.600 LY (319.036 pc) |