Kepler-1542 c
Astrophysical Synthesis & Habitability Characterization
Kepler-1542 c is a confirmed sub-earth exoplanet orbiting the star Kepler-1542, located approximately 1301.7 light-years (399.11 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0036% across the stellar disk), this world measures 0.65 Earth radii and has a measured mass of 0.208 Earth masses. Combining its mass and radius yields a mean bulk density of 4.18 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 0.49 g⊕ (4.81 m/s²), and an escape velocity of 6.3 km/s.
In its orbital architecture around Kepler-1542, Kepler-1542 c completes one full revolution every 2.892 Earth days at a semi-major axis of 0.0387 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 145.6 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 1287 K (+1014°C / +1857°F) and receiving 786.08 S⊕ (~1,069,858 W/m²), Kepler-1542 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1542 is classified as a stellar host with an effective photospheric temperature of 5,564 K, a radius of 0.99 R☉, a mass of 0.94 M☉, an estimated bolometric luminosity of 0.843 L☉. Stellar evolution modeling indicates an estimated stellar age of 8.51 Gyr and a metallicity of [Fe/H] = 0.06 dex (metal-rich relative to the Sun). From Earth, Kepler-1542 shines at apparent V-band magnitude 12.734 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-1542 system is a multi-planet architecture hosting 4 confirmed worlds, with Kepler-1542 c sharing its stellar neighborhood alongside Kepler-1542 b, Kepler-1542 e, Kepler-1542 d.
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-1542 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,564 K |
| Stellar Radius | 0.9900 R☉ |
| Stellar Mass | 0.9400 M☉ |
| Bolometric Luminosity | 0.843 L☉ |
| Metallicity [Fe/H] | 0.060 dex |
| Stellar Age | 8.510 Gyr |
| Apparent Magnitude | V: 12.734 · G: 12.588 |
| System Architecture | 1 Star, 4 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.038700 AU |
| Orbital Period | 2.892 days |
| Mean Orbital Velocity | 145.6 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.8900° |
| Mean Bulk Density | 4.18 g/cm³ (6.3 km/s vesc) |
| Insolation Flux | 786.0820 S⊕ (~1,069,858 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1301.700 LY (399.114 pc) |