TOI-1518 b
Astrophysical Synthesis & Habitability Characterization
TOI-1518 b is a confirmed gas giant exoplanet orbiting the star TOI-1518, located approximately 736.7 light-years (225.89 parsecs) from the Solar System. First announced in 2021 by Multiple Observatories using the Transit detection technique (producing an estimated primary transit depth of 0.9875% across the stellar disk), this world measures 21.05 Earth radii (1.88 Jupiter radii) and has a measured mass of 581.626 Earth masses (1.83 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.34 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.31 g⊕ (12.85 m/s²), and an escape velocity of 58.8 km/s.
In its orbital architecture around TOI-1518, TOI-1518 b completes one full revolution every 1.903 Earth days at a semi-major axis of 0.03712 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 212.3 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.01 (ranging from 0.0367 AU at periapsis to 0.0375 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 2546 K (+2273°C / +4123°F) and receiving 7,010.00 S⊕ (~9,540,610 W/m²), TOI-1518 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-1518 is classified as a warm F-type star of spectral type F0 with an effective photospheric temperature of 7,299 K, a radius of 1.942 R☉, a mass of 1.88 M☉, an estimated bolometric luminosity of 9.604 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.1 dex (near-solar heavy-element abundance). From Earth, TOI-1518 shines at apparent V-band magnitude 8.952 (accessible to binoculars and small amateur telescopes) 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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | TOI-1518 |
| Spectral Type | F0 |
| Effective Temp (Teff) | 7,299 K |
| Stellar Radius | 1.9420 R☉ |
| Stellar Mass | 1.8800 M☉ |
| Bolometric Luminosity | 9.604 L☉ |
| Metallicity [Fe/H] | -0.100 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 8.952 · G: 8.895 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.037120 AU |
| Orbital Period | 1.903 days |
| Mean Orbital Velocity | 212.3 km/s |
| Orbital Eccentricity (e) | 0.01000 |
| Orbital Inclination (i) | 77.6260° |
| Mean Bulk Density | 0.34 g/cm³ (58.8 km/s vesc) |
| Insolation Flux | 7010.0000 S⊕ (~9,540,610 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 736.700 LY (225.888 pc) |