Kepler-1958 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1958 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1958, located approximately 4306.5 light-years (1320.38 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0474% across the stellar disk), this world measures 2.051 Earth radii and has a measured mass of 4.86 Earth masses. Combining its mass and radius yields a mean bulk density of 3.11 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.16 g⊕ (11.38 m/s²), and an escape velocity of 17.2 km/s.
In its orbital architecture around Kepler-1958, Kepler-1958 b completes one full revolution every 9.329 Earth days at a semi-major axis of 0.0856 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 99.8 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 806 K (+533°C / +991°F) and receiving 99.60 S⊕ (~135,556 W/m²), Kepler-1958 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1958 is classified as a stellar host with an effective photospheric temperature of 5,749 K, a radius of 0.864 R☉, a mass of 0.961 M☉, an estimated bolometric luminosity of 0.732 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.1 dex (near-solar heavy-element abundance). From Earth, Kepler-1958 shines at apparent V-band magnitude 15.486 (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-1958 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,749 K |
| Stellar Radius | 0.8640 R☉ |
| Stellar Mass | 0.9610 M☉ |
| Bolometric Luminosity | 0.732 L☉ |
| Metallicity [Fe/H] | -0.100 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 15.486 · G: 15.431 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.085600 AU |
| Orbital Period | 9.329 days |
| Mean Orbital Velocity | 99.8 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.9600° |
| Mean Bulk Density | 3.11 g/cm³ (17.2 km/s vesc) |
| Insolation Flux | 99.6000 S⊕ (~135,556 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 4306.500 LY (1320.380 pc) |