TOI-5624 d
Astrophysical Synthesis & Habitability Characterization
TOI-5624 d is a confirmed sub-neptune exoplanet orbiting the star TOI-5624, located approximately 332.4 light-years (101.91 parsecs) from the Solar System. First announced in 2026 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.1606% across the stellar disk), this world measures 3.584 Earth radii (0.32 Jupiter radii) and has a measured mass of 4.9 Earth masses. Combining its mass and radius yields a mean bulk density of 0.59 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.38 g⊕ (3.73 m/s²), and an escape velocity of 13.1 km/s.
In its orbital architecture around TOI-5624, TOI-5624 d completes one full revolution every 13.731 Earth days at a semi-major axis of 0.1067 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 84.5 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 713 K (+440°C / +824°F) and receiving 157.06 S⊕ (~213,752 W/m²), TOI-5624 d orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-5624 is classified as a stellar host with an effective photospheric temperature of 5,327 K, a radius of 0.82 R☉, a mass of 0.858 M☉, an estimated bolometric luminosity of 0.486 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.7 Gyr and a metallicity of [Fe/H] = -0.023 dex (near-solar heavy-element abundance). From Earth, TOI-5624 shines at apparent V-band magnitude 10.81 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The TOI-5624 system is a multi-planet architecture hosting 5 confirmed worlds, with TOI-5624 d sharing its stellar neighborhood alongside TOI-5624 b, TOI-5624 c, TOI-5624 e, TOI-5624 f.
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-5624 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,327 K |
| Stellar Radius | 0.8200 R☉ |
| Stellar Mass | 0.8580 M☉ |
| Bolometric Luminosity | 0.486 L☉ |
| Metallicity [Fe/H] | -0.023 dex |
| Stellar Age | 5.700 Gyr |
| Apparent Magnitude | V: 10.810 · G: 10.543 |
| System Architecture | 1 Star, 5 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.106700 AU |
| Orbital Period | 13.731 days |
| Mean Orbital Velocity | 84.5 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.6900° |
| Mean Bulk Density | 0.59 g/cm³ (13.1 km/s vesc) |
| Insolation Flux | 157.0550 S⊕ (~213,752 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 332.400 LY (101.913 pc) |