TOI-2578 b
Astrophysical Synthesis & Habitability Characterization
TOI-2578 b is a confirmed gas giant exoplanet orbiting the star TOI-2578, located approximately 931.3 light-years (285.53 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 1.208% across the stellar disk), this world measures 19.661 Earth radii (1.75 Jupiter radii) and has a measured mass of 167.178 Earth masses (0.53 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.12 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.43 g⊕ (4.22 m/s²), and an escape velocity of 32.6 km/s.
In its orbital architecture around TOI-2578, TOI-2578 b completes one full revolution every 3.458 Earth days at a semi-major axis of 0.0495 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 155.7 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.098 carries the world between 0.0446 AU at periapsis and 0.0544 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1778 K (+1505°C / +2741°F) and receiving 1,667.00 S⊕ (~2,268,787 W/m²), TOI-2578 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-2578 is classified as a stellar host with an effective photospheric temperature of 6,333 K, a radius of 1.64 R☉, a mass of 1.27 M☉, an estimated bolometric luminosity of 3.882 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.6 Gyr and a metallicity of [Fe/H] = 0.01 dex (near-solar heavy-element abundance). From Earth, TOI-2578 shines at apparent V-band magnitude 11.353 (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-2578 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,333 K |
| Stellar Radius | 1.6400 R☉ |
| Stellar Mass | 1.2700 M☉ |
| Bolometric Luminosity | 3.882 L☉ |
| Metallicity [Fe/H] | 0.010 dex |
| Stellar Age | 5.600 Gyr |
| Apparent Magnitude | V: 11.353 · G: 11.121 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.049500 AU |
| Orbital Period | 3.458 days |
| Mean Orbital Velocity | 155.7 km/s |
| Orbital Eccentricity (e) | 0.09800 |
| Orbital Inclination (i) | 81.3200° |
| Mean Bulk Density | 0.12 g/cm³ (32.6 km/s vesc) |
| Insolation Flux | 1667.0000 S⊕ (~2,268,787 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 931.300 LY (285.530 pc) |