HD 137496 c
Astrophysical Synthesis & Habitability Characterization
HD 137496 c is a confirmed gas giant exoplanet orbiting the star HD 137496, located approximately 506.6 light-years (155.32 parsecs) from the Solar System. First announced in 2021 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.6 Earth radii (1.12 Jupiter radii) and has a measured mass of 2434.566 Earth masses (7.66 Jupiter masses). Combining its mass and radius yields a mean bulk density of 6.71 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 15.33 g⊕ (150.34 m/s²), and an escape velocity of 155.5 km/s.
In its orbital architecture around HD 137496, HD 137496 c completes one full revolution every 479.9 Earth days (1.31Julian years) at a semi-major axis of 1.2163 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 27.6 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.477, swinging from 0.6361 AU at periapsis out to 1.7965 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 370 K (+97°C / +207°F) and receiving 1.57 S⊕ (~2,139 W/m²), HD 137496 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 137496 is classified as a solar-type yellow star of spectral type G with an effective photospheric temperature of 5,799 K, a radius of 1.59 R☉, a mass of 1.04 M☉, an estimated bolometric luminosity of 2.565 L☉. Stellar evolution modeling indicates an estimated stellar age of 8.3 Gyr and a metallicity of [Fe/H] = -0.03 dex (near-solar heavy-element abundance). From Earth, HD 137496 shines at apparent V-band magnitude 9.899 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The HD 137496 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 137496 c sharing its stellar neighborhood alongside HD 137496 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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 137496 |
| Spectral Type | G |
| Effective Temp (Teff) | 5,799 K |
| Stellar Radius | 1.5900 R☉ |
| Stellar Mass | 1.0400 M☉ |
| Bolometric Luminosity | 2.565 L☉ |
| Metallicity [Fe/H] | -0.030 dex |
| Stellar Age | 8.300 Gyr |
| Apparent Magnitude | V: 9.899 · G: 9.772 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.216300 AU |
| Orbital Period | 479.9 days |
| Mean Orbital Velocity | 27.6 km/s |
| Orbital Eccentricity (e) | 0.47700 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 6.71 g/cm³ (155.5 km/s vesc) |
| Insolation Flux | 1.5713 S⊕ (~2,139 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 506.600 LY (155.317 pc) |