TOI-628 b
Astrophysical Synthesis & Habitability Characterization
TOI-628 b is a confirmed gas giant exoplanet orbiting the star TOI-628, located approximately 582.8 light-years (178.68 parsecs) from the Solar System. First announced in 2021 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.656% across the stellar disk), this world measures 11.882 Earth radii (1.06 Jupiter radii) and has a measured mass of 2011.864 Earth masses (6.33 Jupiter masses). Combining its mass and radius yields a mean bulk density of 6.61 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 14.25 g⊕ (139.74 m/s²), and an escape velocity of 145.6 km/s.
In its orbital architecture around TOI-628, TOI-628 b completes one full revolution every 3.41 Earth days at a semi-major axis of 0.0486 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 155.1 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.072 carries the world between 0.0451 AU at periapsis and 0.0521 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1586 K (+1313°C / +2395°F) and receiving 1,052.90 S⊕ (~1,432,997 W/m²), TOI-628 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-628 is classified as a stellar host with an effective photospheric temperature of 6,250 K, a radius of 1.345 R☉, a mass of 1.311 M☉, an estimated bolometric luminosity of 2.477 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.28 Gyr and a metallicity of [Fe/H] = 0.258 dex (metal-rich relative to the Sun). From Earth, TOI-628 shines at apparent V-band magnitude 10.112 (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-628 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,250 K |
| Stellar Radius | 1.3450 R☉ |
| Stellar Mass | 1.3110 M☉ |
| Bolometric Luminosity | 2.477 L☉ |
| Metallicity [Fe/H] | 0.258 dex |
| Stellar Age | 1.280 Gyr |
| Apparent Magnitude | V: 10.112 · G: 10.058 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.048600 AU |
| Orbital Period | 3.41 days |
| Mean Orbital Velocity | 155.1 km/s |
| Orbital Eccentricity (e) | 0.07200 |
| Orbital Inclination (i) | 88.4100° |
| Mean Bulk Density | 6.61 g/cm³ (145.6 km/s vesc) |
| Insolation Flux | 1052.9000 S⊕ (~1,432,997 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 582.800 LY (178.680 pc) |