TOI-5628 A b
Astrophysical Synthesis & Habitability Characterization
TOI-5628 A b is a confirmed gas giant exoplanet orbiting the star TOI-5628 A, located approximately 358.9 light-years (110.03 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 4.721% across the stellar disk), this world measures 8.295 Earth radii (0.74 Jupiter radii) and has a measured mass of 28.605 Earth masses. Combining its mass and radius yields a mean bulk density of 0.28 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.42 g⊕ (4.12 m/s²), and an escape velocity of 20.8 km/s.
In its orbital architecture around TOI-5628 A, TOI-5628 A b completes one full revolution every 4.342 Earth days at a semi-major axis of 0.0368 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 92.2 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 492 K (+219°C / +426°F) and receiving 45.51 S⊕ (~61,940 W/m²), TOI-5628 A b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-5628 A is classified as a low-mass red dwarf of spectral type M3.0±1.0 with an effective photospheric temperature of 3,310 K, a radius of 0.35 R☉, a mass of 0.36 M☉, an estimated bolometric luminosity of 0.013 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.1 dex (near-solar heavy-element abundance). From Earth, TOI-5628 A shines at apparent V-band magnitude 17.75 (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-5628 A |
| Spectral Type | M3.0±1.0 |
| Effective Temp (Teff) | 3,310 K |
| Stellar Radius | 0.3500 R☉ |
| Stellar Mass | 0.3600 M☉ |
| Bolometric Luminosity | 0.013 L☉ |
| Metallicity [Fe/H] | -0.100 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 17.750 · G: 15.596 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.036800 AU |
| Orbital Period | 4.342 days |
| Mean Orbital Velocity | 92.2 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.9800° |
| Mean Bulk Density | 0.28 g/cm³ (20.8 km/s vesc) |
| Insolation Flux | 45.5107 S⊕ (~61,940 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 358.900 LY (110.030 pc) |