Kepler-1073 d
Astrophysical Synthesis & Habitability Characterization
Kepler-1073 d is a confirmed super-earth exoplanet orbiting the star Kepler-1073, located approximately 2641.5 light-years (809.9 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0149% across the stellar disk), this world measures 1.488 Earth radii and has a measured mass of 2.82 Earth masses. Combining its mass and radius yields a mean bulk density of 4.72 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.27 g⊕ (12.45 m/s²), and an escape velocity of 15.4 km/s.
In its orbital architecture around Kepler-1073, Kepler-1073 d completes one full revolution every 2.505 Earth days at a semi-major axis of 0.0352 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 152.9 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 1369 K (+1096°C / +2005°F) and receiving 828.59 S⊕ (~1,127,711 W/m²), Kepler-1073 d orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1073 is classified as a stellar host with an effective photospheric temperature of 5,509 K, a radius of 1.116 R☉, a mass of 0.924 M☉, an estimated bolometric luminosity of 1.029 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.72 Gyr and a metallicity of [Fe/H] = 0.16 dex (metal-rich relative to the Sun). From Earth, Kepler-1073 shines at apparent V-band magnitude 14.749 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-1073 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-1073 d sharing its stellar neighborhood alongside Kepler-1073 c, Kepler-1073 b.
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-1073 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,509 K |
| Stellar Radius | 1.1160 R☉ |
| Stellar Mass | 0.9240 M☉ |
| Bolometric Luminosity | 1.029 L☉ |
| Metallicity [Fe/H] | 0.160 dex |
| Stellar Age | 3.720 Gyr |
| Apparent Magnitude | V: 14.749 · G: 14.532 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.035200 AU |
| Orbital Period | 2.505 days |
| Mean Orbital Velocity | 152.9 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.0800° |
| Mean Bulk Density | 4.72 g/cm³ (15.4 km/s vesc) |
| Insolation Flux | 828.5900 S⊕ (~1,127,711 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2641.500 LY (809.897 pc) |