TOI-1873 b
Astrophysical Synthesis & Habitability Characterization
TOI-1873 b is a confirmed sub-neptune exoplanet orbiting the star TOI-1873, located approximately 593.6 light-years (182.01 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 0.073% across the stellar disk), this world measures 2.864 Earth radii and has a measured mass of 8.57 Earth masses. Combining its mass and radius yields a mean bulk density of 2.01 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.04 g⊕ (10.2 m/s²), and an escape velocity of 19.3 km/s.
In its orbital architecture around TOI-1873, TOI-1873 b completes one full revolution every 7.006 Earth days.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 924 K (+651°C / +1204°F) and receiving 171.89 S⊕ (~233,947 W/m²), TOI-1873 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-1873 is classified as a stellar host with an effective photospheric temperature of 5,598 K, a radius of 0.9717 R☉, a mass of 1.015 M☉, an estimated bolometric luminosity of 0.832 L☉. From Earth, TOI-1873 shines at apparent V-band magnitude 11.215 (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-1873 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,598 K |
| Stellar Radius | 0.9717 R☉ |
| Stellar Mass | 1.0150 M☉ |
| Bolometric Luminosity | 0.832 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | — |
| Apparent Magnitude | V: 11.215 · G: 11.214 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | — |
| Orbital Period | 7.006 days |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 87.7492° |
| Mean Bulk Density | 2.01 g/cm³ (19.3 km/s vesc) |
| Insolation Flux | 171.8936 S⊕ (~233,947 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 593.600 LY (182.014 pc) |