Ross 176 b
Astrophysical Synthesis & Habitability Characterization
Ross 176 b is a confirmed super-earth exoplanet orbiting the star Ross 176, located approximately 151.5 light-years (46.45 parsecs) from the Solar System. First announced in 2025 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.0879% across the stellar disk), this world measures 1.84 Earth radii and has a measured mass of 4.57 Earth masses. Combining its mass and radius yields a mean bulk density of 4.05 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.35 g⊕ (13.24 m/s²), and an escape velocity of 17.6 km/s.
In its orbital architecture around Ross 176, Ross 176 b completes one full revolution every 5.007 Earth days at a semi-major axis of 0.0464 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 100.8 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.25, swinging from 0.0348 AU at periapsis out to 0.058 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 682 K (+409°C / +768°F) and receiving 36.20 S⊕ (~49,268 W/m²), Ross 176 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Ross 176 is classified as an orange K-type star of spectral type K7 V with an effective photospheric temperature of 4,041 K, a radius of 0.569 R☉, a mass of 0.577 M☉, an estimated bolometric luminosity of 0.077 L☉. Stellar evolution modeling indicates an estimated stellar age of 3 Gyr and a metallicity of [Fe/H] = -0.19 dex (metal-poor relative to the Sun). From Earth, Ross 176 shines at apparent V-band magnitude 11.524 (faint and requiring research-grade or CCD telescopic photometry) 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: Transiting Exoplanet Survey Satellite (TESS) · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | Ross 176 |
| Spectral Type | K7 V |
| Effective Temp (Teff) | 4,041 K |
| Stellar Radius | 0.5690 R☉ |
| Stellar Mass | 0.5770 M☉ |
| Bolometric Luminosity | 0.077 L☉ |
| Metallicity [Fe/H] | -0.190 dex |
| Stellar Age | 3.000 Gyr |
| Apparent Magnitude | V: 11.524 · G: 11.272 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.046400 AU |
| Orbital Period | 5.007 days |
| Mean Orbital Velocity | 100.8 km/s |
| Orbital Eccentricity (e) | 0.25000 |
| Orbital Inclination (i) | 89.4200° |
| Mean Bulk Density | 4.05 g/cm³ (17.6 km/s vesc) |
| Insolation Flux | 36.2000 S⊕ (~49,268 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 151.500 LY (46.449 pc) |