GJ 740 b
Astrophysical Synthesis & Habitability Characterization
GJ 740 b is a confirmed super-earth exoplanet orbiting the star GJ 740, located approximately 36.2 light-years (11.1 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 1.53 Earth radii and has a measured mass of 2.96 Earth masses. Combining its mass and radius yields a mean bulk density of 4.56 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.26 g⊕ (12.36 m/s²), and an escape velocity of 15.6 km/s.
In its orbital architecture around GJ 740, GJ 740 b completes one full revolution every 2.378 Earth days at a semi-major axis of 0.029 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 132.7 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.24 carries the world between 0.022 AU at periapsis and 0.036 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 829 K (+556°C / +1033°F) and receiving 79.00 S⊕ (~107,519 W/m²), GJ 740 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star GJ 740 is classified as a low-mass red dwarf of spectral type M1.0 V with an effective photospheric temperature of 3,913 K, a radius of 0.56 R☉, a mass of 0.58 M☉, an estimated bolometric luminosity of 0.066 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.08 dex (metal-rich relative to the Sun). From Earth, GJ 740 shines at apparent V-band magnitude 9.22 (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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | GJ 740 |
| Spectral Type | M1.0 V |
| Effective Temp (Teff) | 3,913 K |
| Stellar Radius | 0.5600 R☉ |
| Stellar Mass | 0.5800 M☉ |
| Bolometric Luminosity | 0.066 L☉ |
| Metallicity [Fe/H] | 0.080 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 9.220 · G: 8.456 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.029000 AU |
| Orbital Period | 2.378 days |
| Mean Orbital Velocity | 132.7 km/s |
| Orbital Eccentricity (e) | 0.24000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 4.56 g/cm³ (15.6 km/s vesc) |
| Insolation Flux | 79.0000 S⊕ (~107,519 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 36.200 LY (11.102 pc) |