TOI-3540 A b
Astrophysical Synthesis & Habitability Characterization
TOI-3540 A b is a confirmed gas giant exoplanet orbiting the star TOI-3540 A. First announced in 2022 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 3.0883% across the stellar disk), this world measures 23.539 Earth radii (2.1 Jupiter radii) and has a measured mass of 375.038 Earth masses (1.18 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.16 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.68 g⊕ (6.67 m/s²), and an escape velocity of 44.6 km/s.
In its orbital architecture around TOI-3540 A, TOI-3540 A b completes one full revolution every 3.12 Earth days at a semi-major axis of 0.04289 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 149.6 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 1498 K (+1225°C / +2237°F) and receiving 841.30 S⊕ (~1,145,009 W/m²), TOI-3540 A b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-3540 A is classified as a stellar host with an effective photospheric temperature of 5,810 K, a radius of 1.228 R☉, a mass of 1.081 M☉, an estimated bolometric luminosity of 1.542 L☉. Stellar evolution modeling indicates an estimated stellar age of 6 Gyr and a metallicity of [Fe/H] = 0.176 dex (metal-rich relative to the Sun). From Earth, TOI-3540 A shines at apparent V-band magnitude 11.514 (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-3540 A |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,810 K |
| Stellar Radius | 1.2280 R☉ |
| Stellar Mass | 1.0810 M☉ |
| Bolometric Luminosity | 1.542 L☉ |
| Metallicity [Fe/H] | 0.176 dex |
| Stellar Age | 6.000 Gyr |
| Apparent Magnitude | V: 11.514 · G: 11.404 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.042890 AU |
| Orbital Period | 3.12 days |
| Mean Orbital Velocity | 149.6 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 81.9300° |
| Mean Bulk Density | 0.16 g/cm³ (44.6 km/s vesc) |
| Insolation Flux | 841.3000 S⊕ (~1,145,009 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | — |