Kepler-290 d
Astrophysical Synthesis & Habitability Characterization
Kepler-290 d is a confirmed terrestrial exoplanet orbiting the star Kepler-290, located approximately 2265.6 light-years (694.63 parsecs) from the Solar System. First announced in 2023 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0109% across the stellar disk), this world measures 0.86 Earth radii and has a measured mass of 0.566 Earth masses. Combining its mass and radius yields a mean bulk density of 4.91 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 0.77 g⊕ (7.55 m/s²), and an escape velocity of 9.1 km/s.
In its orbital architecture around Kepler-290, Kepler-290 d completes one full revolution every 0.764 Earth days at a semi-major axis of 0.0154 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 219.3 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 1589 K (+1316°C / +2401°F) and receiving 1,503.79 S⊕ (~2,046,658 W/m²), Kepler-290 d orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-290 is classified as a stellar host with an effective photospheric temperature of 5,142 K, a radius of 0.755 R☉, a mass of 0.84 M☉, an estimated bolometric luminosity of 0.358 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.1 Gyr and a metallicity of [Fe/H] = -0.06 dex (near-solar heavy-element abundance). From Earth, Kepler-290 shines at apparent V-band magnitude 15.775 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-290 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-290 d sharing its stellar neighborhood alongside Kepler-290 b, Kepler-290 c.
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-290 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,142 K |
| Stellar Radius | 0.7550 R☉ |
| Stellar Mass | 0.8400 M☉ |
| Bolometric Luminosity | 0.358 L☉ |
| Metallicity [Fe/H] | -0.060 dex |
| Stellar Age | 1.100 Gyr |
| Apparent Magnitude | V: 15.775 · G: 15.565 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.015400 AU |
| Orbital Period | 0.764 days |
| Mean Orbital Velocity | 219.3 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 84.7900° |
| Mean Bulk Density | 4.91 g/cm³ (9.1 km/s vesc) |
| Insolation Flux | 1503.7900 S⊕ (~2,046,658 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2265.600 LY (694.627 pc) |