TOI-1648 b
Astrophysical Synthesis & Habitability Characterization
TOI-1648 b is a confirmed sub-neptune exoplanet orbiting the star TOI-1648, located approximately 227.8 light-years (69.84 parsecs) from the Solar System. First announced in 2025 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.0826% across the stellar disk), this world measures 2.54 Earth radii and has a measured mass of 7.4 Earth masses. Combining its mass and radius yields a mean bulk density of 2.49 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.15 g⊕ (11.28 m/s²), and an escape velocity of 19.1 km/s.
In its orbital architecture around TOI-1648, TOI-1648 b completes one full revolution every 7.332 Earth days at a semi-major axis of 0.0694 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 103 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.178 carries the world between 0.057 AU at periapsis and 0.0818 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 799 K (+526°C / +979°F) and receiving 27.40 S⊕ (~37,295 W/m²), TOI-1648 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-1648 is classified as a stellar host with an effective photospheric temperature of 4,850 K, a radius of 0.81 R☉, a mass of 0.83 M☉, an estimated bolometric luminosity of 0.326 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.7 Gyr and a metallicity of [Fe/H] = 0.2 dex (metal-rich relative to the Sun). From Earth, TOI-1648 shines at apparent V-band magnitude 10.43 (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-1648 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,850 K |
| Stellar Radius | 0.8100 R☉ |
| Stellar Mass | 0.8300 M☉ |
| Bolometric Luminosity | 0.326 L☉ |
| Metallicity [Fe/H] | 0.200 dex |
| Stellar Age | 5.700 Gyr |
| Apparent Magnitude | V: 10.430 · G: 10.185 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.069400 AU |
| Orbital Period | 7.332 days |
| Mean Orbital Velocity | 103 km/s |
| Orbital Eccentricity (e) | 0.17800 |
| Orbital Inclination (i) | 88.2900° |
| Mean Bulk Density | 2.49 g/cm³ (19.1 km/s vesc) |
| Insolation Flux | 27.4026 S⊕ (~37,295 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 227.800 LY (69.835 pc) |