iot Dra b
Astrophysical Synthesis & Habitability Characterization
iot Dra b is a confirmed gas giant exoplanet orbiting the star iot Dra, located approximately 102.2 light-years (31.33 parsecs) from the Solar System. First announced in 2002 by Lick Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.4 Earth radii (1.11 Jupiter radii) and has a measured mass of 3756.732 Earth masses (11.82 Jupiter masses). Combining its mass and radius yields a mean bulk density of 10.86 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 24.43 g⊕ (239.58 m/s²), and an escape velocity of 194.7 km/s.
In its orbital architecture around iot Dra, iot Dra b completes one full revolution every 510.854 Earth days (1.4Julian years) at a semi-major axis of 1.453 AU (comparable to the inner terrestrial zone between Venus, Earth at 1.00 AU, and Mars at 1.52 AU). Its mean orbital velocity is approximately 30.9 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.701, swinging from 0.4344 AU at periapsis out to 2.4716 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 619 K (+346°C / +655°F) and receiving 25.00 S⊕ (~34,025 W/m²), iot Dra b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star iot Dra is classified as an orange K-type star of spectral type K2 III with an effective photospheric temperature of 4,504 K, a radius of 11.79 R☉, a mass of 1.54 M☉, an estimated bolometric luminosity of 51.323 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.65 Gyr and a metallicity of [Fe/H] = 0.03 dex (near-solar heavy-element abundance). From Earth, iot Dra shines at apparent V-band magnitude 3.297 (visible to the unaided human eye under dark skies) in the Northern celestial hemisphere. The iot Dra system is a multi-planet architecture hosting 2 confirmed worlds, with iot Dra b sharing its stellar neighborhood alongside iot Dra 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: Lick Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | iot Dra |
| Spectral Type | K2 III |
| Effective Temp (Teff) | 4,504 K |
| Stellar Radius | 11.7900 R☉ |
| Stellar Mass | 1.5400 M☉ |
| Bolometric Luminosity | 51.323 L☉ |
| Metallicity [Fe/H] | 0.030 dex |
| Stellar Age | 2.650 Gyr |
| Apparent Magnitude | V: 3.297 · G: 2.968 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.453000 AU |
| Orbital Period | 510.854 days |
| Mean Orbital Velocity | 30.9 km/s |
| Orbital Eccentricity (e) | 0.70100 |
| Orbital Inclination (i) | 46.0000° |
| Mean Bulk Density | 10.86 g/cm³ (194.7 km/s vesc) |
| Insolation Flux | 24.9999 S⊕ (~34,025 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 102.200 LY (31.328 pc) |