HIP 29442 c
Astrophysical Synthesis & Habitability Characterization
HIP 29442 c is a confirmed super-earth exoplanet orbiting the star TOI-469, located approximately 222.4 light-years (68.19 parsecs) from the Solar System. First announced in 2023 by Paranal Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 1.551 Earth radii and has a measured mass of 4.5 Earth masses. Combining its mass and radius yields a mean bulk density of 6.65 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 1.87 g⊕ (18.34 m/s²), and an escape velocity of 19.1 km/s.
In its orbital architecture around TOI-469, HIP 29442 c completes one full revolution every 3.538 Earth days at a semi-major axis of 0.04518 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 138.9 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1123 K (+850°C / +1562°F) and receiving 451.00 S⊕ (~613,811 W/m²), HIP 29442 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star TOI-469 is classified as a stellar host with an effective photospheric temperature of 5,289 K, a radius of 0.98 R☉, a mass of 0.901 M☉, an estimated bolometric luminosity of 0.674 L☉. Stellar evolution modeling indicates an estimated stellar age of 11.2 Gyr and a metallicity of [Fe/H] = 0.24 dex (metal-rich relative to the Sun). From Earth, TOI-469 shines at apparent V-band magnitude 9.49 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The TOI-469 system is a multi-planet architecture hosting 3 confirmed worlds, with HIP 29442 c sharing its stellar neighborhood alongside HIP 29442 d, TOI-469.01.
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: Paranal Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | TOI-469 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,289 K |
| Stellar Radius | 0.9800 R☉ |
| Stellar Mass | 0.9010 M☉ |
| Bolometric Luminosity | 0.674 L☉ |
| Metallicity [Fe/H] | 0.240 dex |
| Stellar Age | 11.200 Gyr |
| Apparent Magnitude | V: 9.490 · G: 9.275 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.045180 AU |
| Orbital Period | 3.538 days |
| Mean Orbital Velocity | 138.9 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 86.3000° |
| Mean Bulk Density | 6.65 g/cm³ (19.1 km/s vesc) |
| Insolation Flux | 451.0000 S⊕ (~613,811 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 222.400 LY (68.192 pc) |