TOI-375 d
Astrophysical Synthesis & Habitability Characterization
TOI-375 d is a confirmed gas giant exoplanet orbiting the star TOI-375, located approximately 1292.3 light-years (396.21 parsecs) from the Solar System. First announced in 2026 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.6 Earth radii (1.21 Jupiter radii) and has a measured mass of 445.595 Earth masses (1.4 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.98 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.41 g⊕ (23.63 m/s²), and an escape velocity of 64 km/s.
In its orbital architecture around TOI-375, TOI-375 d completes one full revolution every 297.9 Earth days at a semi-major axis of 0.984 AU (comparable to the inner terrestrial zone between Venus, Earth at 1.00 AU, and Mars at 1.52 AU). Its mean orbital velocity is approximately 35.9 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 434 K (+161°C / +322°F) and receiving 5.96 S⊕ (~8,112 W/m²), TOI-375 d orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-375 is classified as a stellar host with an effective photospheric temperature of 5,260 K, a radius of 2.9 R☉, a mass of 1.441 M☉, an estimated bolometric luminosity of 5.776 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.94 Gyr and a metallicity of [Fe/H] = 0.084 dex (metal-rich relative to the Sun). From Earth, TOI-375 shines at apparent V-band magnitude 11.516 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere. The TOI-375 system is a multi-planet architecture hosting 3 confirmed worlds, with TOI-375 d sharing its stellar neighborhood alongside TOI-375 b, TOI-375 c.
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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | TOI-375 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,260 K |
| Stellar Radius | 2.9000 R☉ |
| Stellar Mass | 1.4410 M☉ |
| Bolometric Luminosity | 5.776 L☉ |
| Metallicity [Fe/H] | 0.084 dex |
| Stellar Age | 2.940 Gyr |
| Apparent Magnitude | V: 11.516 · G: 11.047 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.984000 AU |
| Orbital Period | 297.9 days |
| Mean Orbital Velocity | 35.9 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.98 g/cm³ (64 km/s vesc) |
| Insolation Flux | 5.9600 S⊕ (~8,112 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1292.300 LY (396.213 pc) |