TOI-3785 b
Astrophysical Synthesis & Habitability Characterization
TOI-3785 b is a confirmed sub-neptune exoplanet orbiting the star TOI-3785, located approximately 260.2 light-years (79.76 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 0.8882% across the stellar disk), this world measures 5.14 Earth radii (0.46 Jupiter radii) and has a measured mass of 14.95 Earth masses. Combining its mass and radius yields a mean bulk density of 0.61 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.57 g⊕ (5.59 m/s²), and an escape velocity of 19.1 km/s.
In its orbital architecture around TOI-3785, TOI-3785 b completes one full revolution every 4.675 Earth days at a semi-major axis of 0.043 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 100.1 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.11 carries the world between 0.0383 AU at periapsis and 0.0477 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 582 K (+309°C / +588°F) and receiving 19.10 S⊕ (~25,995 W/m²), TOI-3785 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-3785 is classified as a low-mass red dwarf of spectral type M2 V with an effective photospheric temperature of 3,576 K, a radius of 0.5 R☉, a mass of 0.52 M☉, an estimated bolometric luminosity of 0.037 L☉. Stellar evolution modeling indicates an estimated stellar age of 8 Gyr and a metallicity of [Fe/H] = 0.099 dex (metal-rich relative to the Sun). From Earth, TOI-3785 shines at apparent V-band magnitude 14.595 (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-3785 |
| Spectral Type | M2 V |
| Effective Temp (Teff) | 3,576 K |
| Stellar Radius | 0.5000 R☉ |
| Stellar Mass | 0.5200 M☉ |
| Bolometric Luminosity | 0.037 L☉ |
| Metallicity [Fe/H] | 0.099 dex |
| Stellar Age | 8.000 Gyr |
| Apparent Magnitude | V: 14.595 · G: 13.656 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.043000 AU |
| Orbital Period | 4.675 days |
| Mean Orbital Velocity | 100.1 km/s |
| Orbital Eccentricity (e) | 0.11000 |
| Orbital Inclination (i) | 88.1000° |
| Mean Bulk Density | 0.61 g/cm³ (19.1 km/s vesc) |
| Insolation Flux | 19.1000 S⊕ (~25,995 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 260.200 LY (79.763 pc) |