TOI-942 b
Astrophysical Synthesis & Habitability Characterization
TOI-942 b is a confirmed sub-neptune exoplanet orbiting the star TOI-942, located approximately 497.7 light-years (152.6 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 0.1591% across the stellar disk), this world measures 3.89 Earth radii (0.35 Jupiter radii) and has a measured mass of 826.358 Earth masses (2.6 Jupiter masses). Combining its mass and radius yields a mean bulk density of 77.41 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 54.61 g⊕ (535.54 m/s²), and an escape velocity of 163 km/s.
In its orbital architecture around TOI-942, TOI-942 b completes one full revolution every 4.324 Earth days at a semi-major axis of 0.04866 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 122.4 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.34, swinging from 0.0321 AU at periapsis out to 0.0652 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1120 K (+847°C / +1557°F) and receiving 261.86 S⊕ (~356,389 W/m²), TOI-942 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-942 is classified as an orange K-type star of spectral type K2.5 V with an effective photospheric temperature of 4,969 K, a radius of 0.894 R☉, a mass of 0.822 M☉, an estimated bolometric luminosity of 0.437 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.053 Gyr and a metallicity of [Fe/H] = -0.221 dex (metal-poor relative to the Sun). From Earth, TOI-942 shines at apparent V-band magnitude 11.982 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere. The TOI-942 system is a multi-planet architecture hosting 2 confirmed worlds, with TOI-942 b sharing its stellar neighborhood alongside TOI-942 c.
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-942 |
| Spectral Type | K2.5 V |
| Effective Temp (Teff) | 4,969 K |
| Stellar Radius | 0.8940 R☉ |
| Stellar Mass | 0.8220 M☉ |
| Bolometric Luminosity | 0.437 L☉ |
| Metallicity [Fe/H] | -0.221 dex |
| Stellar Age | 0.053 Gyr |
| Apparent Magnitude | V: 11.982 · G: 11.635 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.048660 AU |
| Orbital Period | 4.324 days |
| Mean Orbital Velocity | 122.4 km/s |
| Orbital Eccentricity (e) | 0.34000 |
| Orbital Inclination (i) | 89.9660° |
| Mean Bulk Density | 77.41 g/cm³ (163 km/s vesc) |
| Insolation Flux | 261.8580 S⊕ (~356,389 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 497.700 LY (152.601 pc) |