HD 23472 c
Astrophysical Synthesis & Habitability Characterization
HD 23472 c is a confirmed super-earth exoplanet orbiting the star HD 23472, located approximately 127.3 light-years (39.03 parsecs) from the Solar System. First announced in 2019 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.0583% across the stellar disk), this world measures 1.87 Earth radii and has a measured mass of 3.41 Earth masses. Combining its mass and radius yields a mean bulk density of 2.88 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 0.98 g⊕ (9.61 m/s²), and an escape velocity of 15.1 km/s.
In its orbital architecture around HD 23472, HD 23472 c completes one full revolution every 29.797 Earth days at a semi-major axis of 0.1646 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 60.1 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.063 carries the world between 0.1542 AU at periapsis and 0.175 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 467 K (+194°C / +381°F) and receiving 7.96 S⊕ (~10,834 W/m²), HD 23472 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 23472 is classified as an orange K-type star of spectral type K4 V with an effective photospheric temperature of 4,684 K, a radius of 0.71 R☉, a mass of 0.67 M☉, an estimated bolometric luminosity of 0.218 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.2 dex (metal-poor relative to the Sun). From Earth, HD 23472 shines at apparent V-band magnitude 9.73 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The HD 23472 system is a multi-planet architecture hosting 5 confirmed worlds, with HD 23472 c sharing its stellar neighborhood alongside HD 23472 d, HD 23472 e, HD 23472 f, HD 23472 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: Transiting Exoplanet Survey Satellite (TESS) · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 23472 |
| Spectral Type | K4 V |
| Effective Temp (Teff) | 4,684 K |
| Stellar Radius | 0.7100 R☉ |
| Stellar Mass | 0.6700 M☉ |
| Bolometric Luminosity | 0.218 L☉ |
| Metallicity [Fe/H] | -0.200 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 9.730 · G: 9.385 |
| System Architecture | 1 Star, 5 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.164600 AU |
| Orbital Period | 29.797 days |
| Mean Orbital Velocity | 60.1 km/s |
| Orbital Eccentricity (e) | 0.06300 |
| Orbital Inclination (i) | 89.0950° |
| Mean Bulk Density | 2.88 g/cm³ (15.1 km/s vesc) |
| Insolation Flux | 7.9600 S⊕ (~10,834 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 127.300 LY (39.034 pc) |