TOI-849 b
Astrophysical Synthesis & Habitability Characterization
TOI-849 b is a confirmed sub-neptune exoplanet orbiting the star TOI-849, located approximately 736.2 light-years (225.73 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 0.1184% across the stellar disk), this world measures 3.64 Earth radii (0.32 Jupiter radii) and has a measured mass of 41.8 Earth masses (0.13 Jupiter masses). Combining its mass and radius yields a mean bulk density of 4.78 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 3.15 g⊕ (30.89 m/s²), and an escape velocity of 37.9 km/s.
In its orbital architecture around TOI-849, TOI-849 b completes one full revolution every 0.766 Earth days at a semi-major axis of 0.0155 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 220.3 km/s (compared to Earth's 29.8 km/s). 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 1932 K (+1659°C / +3018°F) and receiving 2,314.06 S⊕ (~3,149,436 W/m²), TOI-849 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-849 is classified as a solar-type yellow star of spectral type G with an effective photospheric temperature of 5,257 K, a radius of 0.97 R☉, a mass of 0.97 M☉, an estimated bolometric luminosity of 0.645 L☉. Stellar evolution modeling indicates an estimated stellar age of 6.7 Gyr and a metallicity of [Fe/H] = 0.19 dex (metal-rich relative to the Sun). From Earth, TOI-849 shines at apparent V-band magnitude 11.981 (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-849 |
| Spectral Type | G |
| Effective Temp (Teff) | 5,257 K |
| Stellar Radius | 0.9700 R☉ |
| Stellar Mass | 0.9700 M☉ |
| Bolometric Luminosity | 0.645 L☉ |
| Metallicity [Fe/H] | 0.190 dex |
| Stellar Age | 6.700 Gyr |
| Apparent Magnitude | V: 11.981 · G: 12.065 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.015500 AU |
| Orbital Period | 0.766 days |
| Mean Orbital Velocity | 220.3 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 86.8000° |
| Mean Bulk Density | 4.78 g/cm³ (37.9 km/s vesc) |
| Insolation Flux | 2314.0600 S⊕ (~3,149,436 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 736.200 LY (225.734 pc) |