TOI-540 b
Astrophysical Synthesis & Habitability Characterization
TOI-540 b is a confirmed terrestrial exoplanet orbiting the star TOI-540, located approximately 45.7 light-years (14 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 0.1909% across the stellar disk), this world measures 0.903 Earth radii and has a measured mass of 0.674 Earth masses. Combining its mass and radius yields a mean bulk density of 5.05 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 0.83 g⊕ (8.14 m/s²), and an escape velocity of 9.7 km/s.
In its orbital architecture around TOI-540, TOI-540 b completes one full revolution every 1.239 Earth days at a semi-major axis of 0.01223 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 107.4 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 611 K (+338°C / +640°F) and receiving 23.40 S⊕ (~31,847 W/m²), TOI-540 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-540 is classified as a low-mass red dwarf of spectral type M V with an effective photospheric temperature of 3,216 K, a radius of 0.1895 R☉, a mass of 0.159 M☉, an estimated bolometric luminosity of 0.00345 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.1 Gyr. From Earth, TOI-540 shines at apparent V-band magnitude 14.823 (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-540 |
| Spectral Type | M V |
| Effective Temp (Teff) | 3,216 K |
| Stellar Radius | 0.1895 R☉ |
| Stellar Mass | 0.1590 M☉ |
| Bolometric Luminosity | 0.00345 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | 1.100 Gyr |
| Apparent Magnitude | V: 14.823 · G: 12.894 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.012230 AU |
| Orbital Period | 1.239 days |
| Mean Orbital Velocity | 107.4 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 86.8000° |
| Mean Bulk Density | 5.05 g/cm³ (9.7 km/s vesc) |
| Insolation Flux | 23.4000 S⊕ (~31,847 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 45.700 LY (14.002 pc) |