TOI-1776 b
Astrophysical Synthesis & Habitability Characterization
TOI-1776 b is a confirmed terrestrial exoplanet orbiting the star TOI-1776, located approximately 145.6 light-years (44.65 parsecs) from the Solar System. First announced in 2024 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.0142% across the stellar disk), this world measures 1.216 Earth radii and has a measured mass of 1.4 Earth masses. Combining its mass and radius yields a mean bulk density of 4.29 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 0.95 g⊕ (9.32 m/s²), and an escape velocity of 12 km/s.
In its orbital architecture around TOI-1776, TOI-1776 b completes one full revolution every 2.8 Earth days at a semi-major axis of 0.0378 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 146.9 km/s (compared to Earth's 29.8 km/s). The orbit is modeled as circular (e = 0.00), maintaining a constant stellar distance throughout its year.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1269 K (+996°C / +1825°F) and receiving 560.33 S⊕ (~762,616 W/m²), TOI-1776 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-1776 is classified as a stellar host with an effective photospheric temperature of 5,785 K, a radius of 0.9356 R☉, a mass of 0.9196 M☉, an estimated bolometric luminosity of 0.88 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.1 Gyr and a metallicity of [Fe/H] = -0.193 dex (metal-poor relative to the Sun). From Earth, TOI-1776 shines at apparent V-band magnitude 8.26 (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: Transiting Exoplanet Survey Satellite (TESS) · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | TOI-1776 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,785 K |
| Stellar Radius | 0.9356 R☉ |
| Stellar Mass | 0.9196 M☉ |
| Bolometric Luminosity | 0.88 L☉ |
| Metallicity [Fe/H] | -0.193 dex |
| Stellar Age | 5.100 Gyr |
| Apparent Magnitude | V: 8.260 · G: 8.090 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.037800 AU |
| Orbital Period | 2.8 days |
| Mean Orbital Velocity | 146.9 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 4.29 g/cm³ (12 km/s vesc) |
| Insolation Flux | 560.3349 S⊕ (~762,616 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 145.600 LY (44.647 pc) |