BD+15 2940 b
Astrophysical Synthesis & Habitability Characterization
BD+15 2940 b is a confirmed gas giant exoplanet orbiting the star BD+15 2940, located approximately 1390.8 light-years (426.42 parsecs) from the Solar System. First announced in 2013 by McDonald Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.7 Earth radii (1.22 Jupiter radii) and has a measured mass of 352.78 Earth masses (1.11 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.76 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.88 g⊕ (18.44 m/s²), and an escape velocity of 56.8 km/s.
In its orbital architecture around BD+15 2940, BD+15 2940 b completes one full revolution every 137.48 Earth days at a semi-major axis of 0.539 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 42.7 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.26, swinging from 0.3989 AU at periapsis out to 0.6791 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1208 K (+935°C / +1715°F) and receiving 352.23 S⊕ (~479,381 W/m²), BD+15 2940 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star BD+15 2940 is classified as an orange K-type star of spectral type K0 with an effective photospheric temperature of 4,796 K, a radius of 14.7 R☉, a mass of 1.1 M☉, an estimated bolometric luminosity of 102.575 L☉. Stellar evolution modeling indicates an estimated stellar age of 7.1 Gyr and a metallicity of [Fe/H] = 0.28 dex (metal-rich relative to the Sun). From Earth, BD+15 2940 shines at apparent V-band magnitude 9.01 (accessible to binoculars and small amateur telescopes) 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: McDonald Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | BD+15 2940 |
| Spectral Type | K0 |
| Effective Temp (Teff) | 4,796 K |
| Stellar Radius | 14.7000 R☉ |
| Stellar Mass | 1.1000 M☉ |
| Bolometric Luminosity | 102.575 L☉ |
| Metallicity [Fe/H] | 0.280 dex |
| Stellar Age | 7.100 Gyr |
| Apparent Magnitude | V: 9.010 · G: 8.718 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.539000 AU |
| Orbital Period | 137.48 days |
| Mean Orbital Velocity | 42.7 km/s |
| Orbital Eccentricity (e) | 0.26000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.76 g/cm³ (56.8 km/s vesc) |
| Insolation Flux | 352.2269 S⊕ (~479,381 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1390.800 LY (426.420 pc) |