TOI-873 b
Astrophysical Synthesis & Habitability Characterization
TOI-873 b is a confirmed super-earth exoplanet orbiting the star TOI-873, located approximately 251 light-years (76.96 parsecs) from the Solar System. First announced in 2026 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.0845% across the stellar disk), this world measures 1.65 Earth radii and has a measured mass of 3.36 Earth masses. Combining its mass and radius yields a mean bulk density of 4.12 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.23 g⊕ (12.06 m/s²), and an escape velocity of 16 km/s.
In its orbital architecture around TOI-873, TOI-873 b completes one full revolution every 5.931 Earth days. 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 518 K (+245°C / +473°F) and receiving 17.02 S⊕ (~23,163 W/m²), TOI-873 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-873 is classified as a stellar host with an effective photospheric temperature of 3,694 K, a radius of 0.5204 R☉, a mass of 0.5179 M☉, an estimated bolometric luminosity of 0.045 L☉. From Earth, TOI-873 shines at apparent V-band magnitude 13.996 (faint and requiring research-grade or CCD telescopic photometry) in the Southern 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-873 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 3,694 K |
| Stellar Radius | 0.5204 R☉ |
| Stellar Mass | 0.5179 M☉ |
| Bolometric Luminosity | 0.045 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | — |
| Apparent Magnitude | V: 13.996 · G: 13.168 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | — |
| Orbital Period | 5.931 days |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 4.12 g/cm³ (16 km/s vesc) |
| Insolation Flux | 17.0190 S⊕ (~23,163 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 251.000 LY (76.956 pc) |