Kepler-1553 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1553 b is a confirmed terrestrial exoplanet orbiting the star Kepler-1553, located approximately 2258.9 light-years (692.59 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0169% across the stellar disk), this world measures 1.15 Earth radii and has a measured mass of 1.6 Earth masses. Combining its mass and radius yields a mean bulk density of 5.8 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.21 g⊕ (11.87 m/s²), and an escape velocity of 13.2 km/s.
In its orbital architecture around Kepler-1553, Kepler-1553 b completes one full revolution every 4.243 Earth days at a semi-major axis of 0.0481 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 123.3 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 926 K (+653°C / +1207°F) and receiving 166.11 S⊕ (~226,070 W/m²), Kepler-1553 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1553 is classified as a stellar host with an effective photospheric temperature of 5,288 K, a radius of 0.81 R☉, a mass of 0.85 M☉, an estimated bolometric luminosity of 0.46 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.57 Gyr and a metallicity of [Fe/H] = -0.09 dex (near-solar heavy-element abundance). From Earth, Kepler-1553 shines at apparent V-band magnitude 15.251 (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-1553 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,288 K |
| Stellar Radius | 0.8100 R☉ |
| Stellar Mass | 0.8500 M☉ |
| Bolometric Luminosity | 0.46 L☉ |
| Metallicity [Fe/H] | -0.090 dex |
| Stellar Age | 4.570 Gyr |
| Apparent Magnitude | V: 15.251 · G: 14.991 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.048100 AU |
| Orbital Period | 4.243 days |
| Mean Orbital Velocity | 123.3 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.0800° |
| Mean Bulk Density | 5.8 g/cm³ (13.2 km/s vesc) |
| Insolation Flux | 166.1060 S⊕ (~226,070 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2258.900 LY (692.594 pc) |