TOI-1898 b
Astrophysical Synthesis & Habitability Characterization
TOI-1898 b is a confirmed gas giant exoplanet orbiting the star TOI-1898, located approximately 259.8 light-years (79.67 parsecs) from the Solar System. First announced in 2024 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.2852% across the stellar disk), this world measures 9.396 Earth radii (0.84 Jupiter radii) and has a measured mass of 129 Earth masses (0.41 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 1.46 g⊕ (14.32 m/s²), and an escape velocity of 41.4 km/s.
In its orbital architecture around TOI-1898, TOI-1898 b completes one full revolution every 45.522 Earth days at a semi-major axis of 0.269 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 64.3 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.485, swinging from 0.1385 AU at periapsis out to 0.3995 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 675 K (+402°C / +756°F) and receiving 51.01 S⊕ (~69,421 W/m²), TOI-1898 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-1898 is classified as a stellar host with an effective photospheric temperature of 6,241 K, a radius of 1.6131 R☉, a mass of 1.2484 M☉, an estimated bolometric luminosity of 3.542 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.1 Gyr and a metallicity of [Fe/H] = -0.095 dex (near-solar heavy-element abundance). From Earth, TOI-1898 shines at apparent V-band magnitude 7.87 (accessible to binoculars and small amateur telescopes) 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-1898 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,241 K |
| Stellar Radius | 1.6131 R☉ |
| Stellar Mass | 1.2484 M☉ |
| Bolometric Luminosity | 3.542 L☉ |
| Metallicity [Fe/H] | -0.095 dex |
| Stellar Age | 3.100 Gyr |
| Apparent Magnitude | V: 7.870 · G: 7.748 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.269000 AU |
| Orbital Period | 45.522 days |
| Mean Orbital Velocity | 64.3 km/s |
| Orbital Eccentricity (e) | 0.48500 |
| Orbital Inclination (i) | 87.5310° |
| Mean Bulk Density | 0.86 g/cm³ (41.4 km/s vesc) |
| Insolation Flux | 51.0074 S⊕ (~69,421 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 259.800 LY (79.668 pc) |