TOI-1899 b
Astrophysical Synthesis & Habitability Characterization
TOI-1899 b is a confirmed gas giant exoplanet orbiting the star TOI-1899, located approximately 418.9 light-years (128.44 parsecs) from the Solar System. First announced in 2020 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 2.8092% across the stellar disk), this world measures 11.097 Earth radii (0.99 Jupiter radii) and has a measured mass of 212.945 Earth masses (0.67 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.86 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.73 g⊕ (16.97 m/s²), and an escape velocity of 49 km/s.
In its orbital architecture around TOI-1899, TOI-1899 b completes one full revolution every 29.09 Earth days at a semi-major axis of 0.1525 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 57 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.044 (ranging from 0.1458 AU at periapsis to 0.1592 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 378 K (+105°C / +221°F) and receiving 3.40 S⊕ (~4,627 W/m²), TOI-1899 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-1899 is classified as a low-mass red dwarf of spectral type M0 with an effective photospheric temperature of 3,926 K, a radius of 0.607 R☉, a mass of 0.632 M☉, an estimated bolometric luminosity of 0.079 L☉. Stellar evolution modeling indicates an estimated stellar age of 7.1 Gyr and a metallicity of [Fe/H] = 0.28 dex (metal-rich relative to the Sun). From Earth, TOI-1899 shines at apparent V-band magnitude 14.88 (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-1899 |
| Spectral Type | M0 |
| Effective Temp (Teff) | 3,926 K |
| Stellar Radius | 0.6070 R☉ |
| Stellar Mass | 0.6320 M☉ |
| Bolometric Luminosity | 0.079 L☉ |
| Metallicity [Fe/H] | 0.280 dex |
| Stellar Age | 7.100 Gyr |
| Apparent Magnitude | V: 14.880 · G: 13.555 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.152500 AU |
| Orbital Period | 29.09 days |
| Mean Orbital Velocity | 57 km/s |
| Orbital Eccentricity (e) | 0.04400 |
| Orbital Inclination (i) | 89.6400° |
| Mean Bulk Density | 0.86 g/cm³ (49 km/s vesc) |
| Insolation Flux | 3.4000 S⊕ (~4,627 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 418.900 LY (128.438 pc) |