TOI-1853 b
Astrophysical Synthesis & Habitability Characterization
TOI-1853 b is a confirmed sub-neptune exoplanet orbiting the star TOI-1853, located approximately 538.5 light-years (165.11 parsecs) from the Solar System. First announced in 2023 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.1541% across the stellar disk), this world measures 3.46 Earth radii (0.31 Jupiter radii) and has a measured mass of 73.2 Earth masses (0.23 Jupiter masses). Combining its mass and radius yields a mean bulk density of 9.74 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 6.11 g⊕ (59.92 m/s²), and an escape velocity of 51.5 km/s.
In its orbital architecture around TOI-1853, TOI-1853 b completes one full revolution every 1.244 Earth days at a semi-major axis of 0.0213 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 186.3 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.03 (ranging from 0.0207 AU at periapsis to 0.0219 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1479 K (+1206°C / +2203°F) and receiving 435.33 S⊕ (~592,484 W/m²), TOI-1853 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-1853 is classified as an orange K-type star of spectral type K2.5 V with an effective photospheric temperature of 4,985 K, a radius of 0.808 R☉, a mass of 0.837 M☉, an estimated bolometric luminosity of 0.362 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.11 dex (metal-rich relative to the Sun). From Earth, TOI-1853 shines at apparent V-band magnitude 12.178 (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-1853 |
| Spectral Type | K2.5 V |
| Effective Temp (Teff) | 4,985 K |
| Stellar Radius | 0.8080 R☉ |
| Stellar Mass | 0.8370 M☉ |
| Bolometric Luminosity | 0.362 L☉ |
| Metallicity [Fe/H] | 0.110 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 12.178 · G: 11.947 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.021300 AU |
| Orbital Period | 1.244 days |
| Mean Orbital Velocity | 186.3 km/s |
| Orbital Eccentricity (e) | 0.03000 |
| Orbital Inclination (i) | 84.7000° |
| Mean Bulk Density | 9.74 g/cm³ (51.5 km/s vesc) |
| Insolation Flux | 435.3300 S⊕ (~592,484 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 538.500 LY (165.105 pc) |