TOI-1278 b
Astrophysical Synthesis & Habitability Characterization
TOI-1278 b is a confirmed gas giant exoplanet orbiting the star TOI-1278, located approximately 246.5 light-years (75.58 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 3.8215% across the stellar disk), this world measures 12.218 Earth radii (1.09 Jupiter radii) and has a measured mass of 5879.826 Earth masses (18.5 Jupiter masses). Combining its mass and radius yields a mean bulk density of 17.78 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 39.39 g⊕ (386.28 m/s²), and an escape velocity of 245.4 km/s.
In its orbital architecture around TOI-1278, TOI-1278 b completes one full revolution every 14.476 Earth days at a semi-major axis of 0.095 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 71.4 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.013 (ranging from 0.0938 AU at periapsis to 0.0962 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 408 K (+135°C / +275°F) and receiving 6.54 S⊕ (~8,901 W/m²), TOI-1278 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-1278 is classified as a low-mass red dwarf of spectral type M0 V with an effective photospheric temperature of 3,799 K, a radius of 0.573 R☉, a mass of 0.54 M☉, an estimated bolometric luminosity of 0.061 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.01 dex (near-solar heavy-element abundance). From Earth, TOI-1278 shines at apparent V-band magnitude 13.502 (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-1278 |
| Spectral Type | M0 V |
| Effective Temp (Teff) | 3,799 K |
| Stellar Radius | 0.5730 R☉ |
| Stellar Mass | 0.5400 M☉ |
| Bolometric Luminosity | 0.061 L☉ |
| Metallicity [Fe/H] | -0.010 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 13.502 · G: 12.754 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.095000 AU |
| Orbital Period | 14.476 days |
| Mean Orbital Velocity | 71.4 km/s |
| Orbital Eccentricity (e) | 0.01300 |
| Orbital Inclination (i) | 88.3000° |
| Mean Bulk Density | 17.78 g/cm³ (245.4 km/s vesc) |
| Insolation Flux | 6.5402 S⊕ (~8,901 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 246.500 LY (75.576 pc) |