HD 144899 b
Astrophysical Synthesis & Habitability Characterization
HD 144899 b is a confirmed sub-neptune exoplanet orbiting the star HD 144899, located approximately 377.2 light-years (115.67 parsecs) from the Solar System. First announced in 2022 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 4.77 Earth radii (0.43 Jupiter radii) and has a measured mass of 20.341 Earth masses. Combining its mass and radius yields a mean bulk density of 1.03 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.89 g⊕ (8.73 m/s²), and an escape velocity of 23.1 km/s.
In its orbital architecture around HD 144899, HD 144899 b completes one full revolution every 40.439 Earth days at a semi-major axis of 0.242 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 65.1 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.821, swinging from 0.0433 AU at periapsis out to 0.4407 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 771 K (+498°C / +928°F) and receiving 58.84 S⊕ (~80,085 W/m²), HD 144899 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 144899 is classified as a stellar host with an effective photospheric temperature of 6,126 K, a radius of 1.648 R☉, a mass of 1.16 M☉, an estimated bolometric luminosity of 3.432 L☉. From Earth, HD 144899 shines at apparent V-band magnitude 8.97 (accessible to binoculars and small amateur telescopes) in the Southern 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 | HD 144899 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,126 K |
| Stellar Radius | 1.6480 R☉ |
| Stellar Mass | 1.1600 M☉ |
| Bolometric Luminosity | 3.432 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | — |
| Apparent Magnitude | V: 8.970 · G: 8.813 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.242000 AU |
| Orbital Period | 40.439 days |
| Mean Orbital Velocity | 65.1 km/s |
| Orbital Eccentricity (e) | 0.82100 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.03 g/cm³ (23.1 km/s vesc) |
| Insolation Flux | 58.8430 S⊕ (~80,085 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 377.200 LY (115.665 pc) |