TOI-654.01
Astrophysical Synthesis & Habitability Characterization
TOI-654.01 is a confirmed sub-neptune exoplanet orbiting the star TOI-654, located approximately 188.4 light-years (57.76 parsecs) from the Solar System. First announced in 2024 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.2571% across the stellar disk), this world measures 2.378 Earth radii and has a measured mass of 8.71 Earth masses. Combining its mass and radius yields a mean bulk density of 3.57 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.54 g⊕ (15.1 m/s²), and an escape velocity of 21.4 km/s.
In its orbital architecture around TOI-654, TOI-654.01 completes one full revolution every 1.528 Earth days at a semi-major axis of 0.01944 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 138.4 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 794 K (+521°C / +970°F) and receiving 65.00 S⊕ (~88,465 W/m²), TOI-654.01 orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-654 is classified as a low-mass red dwarf of spectral type M2 V with an effective photospheric temperature of 3,521 K, a radius of 0.43 R☉, a mass of 0.419 M☉, an estimated bolometric luminosity of 0.025 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.12 dex (metal-rich relative to the Sun). From Earth, TOI-654 shines at apparent V-band magnitude 14.54 (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-654 |
| Spectral Type | M2 V |
| Effective Temp (Teff) | 3,521 K |
| Stellar Radius | 0.4300 R☉ |
| Stellar Mass | 0.4190 M☉ |
| Bolometric Luminosity | 0.025 L☉ |
| Metallicity [Fe/H] | 0.120 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 14.540 · G: 13.434 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.019440 AU |
| Orbital Period | 1.528 days |
| Mean Orbital Velocity | 138.4 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.2800° |
| Mean Bulk Density | 3.57 g/cm³ (21.4 km/s vesc) |
| Insolation Flux | 65.0000 S⊕ (~88,465 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 188.400 LY (57.755 pc) |