Kepler-1844 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1844 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1844, located approximately 5885 light-years (1804.36 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.1075% across the stellar disk), this world measures 3.036 Earth radii (0.27 Jupiter radii) and has a measured mass of 9.46 Earth masses. Combining its mass and radius yields a mean bulk density of 1.86 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.03 g⊕ (10.1 m/s²), and an escape velocity of 19.7 km/s.
In its orbital architecture around Kepler-1844, Kepler-1844 b completes one full revolution every 3.925 Earth days at a semi-major axis of 0.0478 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 132.5 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 1074 K (+801°C / +1474°F) and receiving 314.25 S⊕ (~427,694 W/m²), Kepler-1844 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1844 is classified as a stellar host with an effective photospheric temperature of 5,776 K, a radius of 0.849 R☉, a mass of 0.939 M☉, an estimated bolometric luminosity of 0.72 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.18 dex (metal-poor relative to the Sun). From Earth, Kepler-1844 shines at apparent V-band magnitude 15.995 (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-1844 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,776 K |
| Stellar Radius | 0.8490 R☉ |
| Stellar Mass | 0.9390 M☉ |
| Bolometric Luminosity | 0.72 L☉ |
| Metallicity [Fe/H] | -0.180 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 15.995 · G: 15.692 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.047800 AU |
| Orbital Period | 3.925 days |
| Mean Orbital Velocity | 132.5 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.2200° |
| Mean Bulk Density | 1.86 g/cm³ (19.7 km/s vesc) |
| Insolation Flux | 314.2500 S⊕ (~427,694 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 5885.000 LY (1804.360 pc) |