TOI-1281 b
Astrophysical Synthesis & Habitability Characterization
TOI-1281 b is a confirmed sub-neptune exoplanet orbiting the star TOI-1281, located approximately 581.4 light-years (178.26 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 0.0345% across the stellar disk), this world measures 2.68 Earth radii and has a measured mass of 7.65 Earth masses. Combining its mass and radius yields a mean bulk density of 2.19 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.07 g⊕ (10.49 m/s²), and an escape velocity of 18.9 km/s.
In its orbital architecture around TOI-1281, TOI-1281 b completes one full revolution every 6.391 Earth days. 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 1227 K (+954°C / +1749°F) and receiving 376.53 S⊕ (~512,460 W/m²), TOI-1281 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-1281 is classified as a stellar host with an effective photospheric temperature of 6,191 K, a radius of 1.3235 R☉, a mass of 1.19 M☉, an estimated bolometric luminosity of 2.309 L☉. From Earth, TOI-1281 shines at apparent V-band magnitude 10.294 (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-1281 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,191 K |
| Stellar Radius | 1.3235 R☉ |
| Stellar Mass | 1.1900 M☉ |
| Bolometric Luminosity | 2.309 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | — |
| Apparent Magnitude | V: 10.294 · G: 10.038 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | — |
| Orbital Period | 6.391 days |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 2.19 g/cm³ (18.9 km/s vesc) |
| Insolation Flux | 376.5320 S⊕ (~512,460 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 581.400 LY (178.259 pc) |