TOI-942 c
Astrophysical Synthesis & Habitability Characterization
TOI-942 c 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 0.2294% across the stellar disk), this world measures 4.67 Earth radii (0.42 Jupiter radii) and has a measured mass of 37 Earth masses (0.12 Jupiter masses). Combining its mass and radius yields a mean bulk density of 2 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.7 g⊕ (16.67 m/s²), and an escape velocity of 31.5 km/s.
In its orbital architecture around TOI-942, TOI-942 c completes one full revolution every 10.156 Earth days at a semi-major axis of 0.08598 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 92.1 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.32, swinging from 0.0585 AU at periapsis out to 0.1135 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 773 K (+500°C / +932°F) and receiving 59.25 S⊕ (~80,638 W/m²), TOI-942 c 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 c sharing its stellar neighborhood alongside TOI-942 b.
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) | 0.085980 AU |
| Orbital Period | 10.156 days |
| Mean Orbital Velocity | 92.1 km/s |
| Orbital Eccentricity (e) | 0.32000 |
| Orbital Inclination (i) | 89.1600° |
| Mean Bulk Density | 2 g/cm³ (31.5 km/s vesc) |
| Insolation Flux | 59.2488 S⊕ (~80,638 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 497.700 LY (152.601 pc) |