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CONFIRMED EXOPLANET · Sub-Neptune

Kepler-1241 b

Orbits Host Star: Kepler-1241 · Distance: 3159.500 Light-Years (968.722 pc)
Planetary Radius
2.630 R⊕
Planetary Mass
7.410 M⊕
Surface Gravity
1.07 g / g⊕
Equilibrium Temp
612K (+339°C / +642°F)
Orbital Period
18.553 days
Discovery Year
2016 (Transit)
Earth Similarity (ESI)
0.40 / 1.00
Insolation Flux
31.46 S⊕

Astrophysical Synthesis & Habitability Characterization

Kepler-1241 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1241, located approximately 3159.5 light-years (968.72 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0908% across the stellar disk), this world measures 2.63 Earth radii and has a measured mass of 7.41 Earth masses. Combining its mass and radius yields a mean bulk density of 2.25 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 18.8 km/s.

In its orbital architecture around Kepler-1241, Kepler-1241 b completes one full revolution every 18.553 Earth days at a semi-major axis of 0.1336 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 78.3 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 612 K (+339°C / +642°F) and receiving 31.46 S⊕ (~42,812 W/m²), Kepler-1241 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1241 is classified as a stellar host with an effective photospheric temperature of 5,261 K, a radius of 0.8 R☉, a mass of 0.84 M☉, an estimated bolometric luminosity of 0.44 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.68 Gyr and a metallicity of [Fe/H] = -0.09 dex (near-solar heavy-element abundance). From Earth, Kepler-1241 shines at apparent V-band magnitude 15.886 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

Earth Similarity Index (ESI): 0.40 Earth Baseline = 1.00
0.00 Dissimilar 0.50 Mars Scale 0.70 Analog Regime 1.00 Earth

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-1241
Spectral Type Unclassified
Effective Temp (Teff) 5,261 K
Stellar Radius 0.8000 R☉
Stellar Mass 0.8400 M☉
Bolometric Luminosity 0.44 L☉
Metallicity [Fe/H] -0.090 dex
Stellar Age 4.680 Gyr
Apparent Magnitude V: 15.886 · G: 15.669
System Architecture 1 Star, 1 Planet

🪐 Orbital & Physical Dynamics

Semi-Major Axis (a) 0.133600 AU
Orbital Period 18.553 days
Mean Orbital Velocity 78.3 km/s
Orbital Eccentricity (e) 0.00000
Orbital Inclination (i) 87.9400°
Mean Bulk Density 2.25 g/cm³ (18.8 km/s vesc)
Insolation Flux 31.4560 S⊕ (~42,812 W/m²)
Habitable Zone Status Exterior / Non-HZ
Celestial Distance 3159.500 LY (968.722 pc)

🔭 Deep Space Viewport // Host Star Field

RA: 19h38m18.29s · DEC: +38d27m25.05s (J2000: 294.5762°, 38.45696°)
Target Field: Kepler-1241 (J2000 294.5762°, 38.45696°)
Surveys available: Digitized Sky Survey (DSS2 Optical), 2MASS (Near-Infrared), AllWISE (Mid-Infrared) · Field of View: 0.18° (10.8 arcmin)
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