Kepler-961 b
Astrophysical Synthesis & Habitability Characterization
Kepler-961 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-961, located approximately 1873.2 light-years (574.31 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0675% across the stellar disk), this world measures 2.55 Earth radii and has a measured mass of 7.04 Earth masses. Combining its mass and radius yields a mean bulk density of 2.34 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.08 g⊕ (10.59 m/s²), and an escape velocity of 18.6 km/s.
In its orbital architecture around Kepler-961, Kepler-961 b completes one full revolution every 16.877 Earth days at a semi-major axis of 0.12585 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 81.1 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 642 K (+369°C / +696°F) and receiving 40.40 S⊕ (~54,984 W/m²), Kepler-961 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-961 is classified as a stellar host with an effective photospheric temperature of 5,582 K, a radius of 0.9 R☉, a mass of 0.96 M☉, an estimated bolometric luminosity of 0.706 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.82 Gyr and a metallicity of [Fe/H] = 0.05 dex (near-solar heavy-element abundance). From Earth, Kepler-961 shines at apparent V-band magnitude 14.204 (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: Kepler · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | Kepler-961 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,582 K |
| Stellar Radius | 0.9000 R☉ |
| Stellar Mass | 0.9600 M☉ |
| Bolometric Luminosity | 0.706 L☉ |
| Metallicity [Fe/H] | 0.050 dex |
| Stellar Age | 2.820 Gyr |
| Apparent Magnitude | V: 14.204 · G: 14.043 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.125850 AU |
| Orbital Period | 16.877 days |
| Mean Orbital Velocity | 81.1 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.0200° |
| Mean Bulk Density | 2.34 g/cm³ (18.6 km/s vesc) |
| Insolation Flux | 40.4000 S⊕ (~54,984 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1873.200 LY (574.314 pc) |