PSR B1257+12 d
Astrophysical Synthesis & Habitability Characterization
PSR B1257+12 d is a confirmed super-earth exoplanet orbiting the star PSR B1257+12, located approximately 1956.9 light-years (600 parsecs) from the Solar System. First announced in 1992 by Arecibo Observatory using the Pulsar Timing detection technique, this world measures 1.8 Earth radii and has a measured mass of 3.9 Earth masses. Combining its mass and radius yields a mean bulk density of 3.69 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.2 g⊕ (11.77 m/s²), and an escape velocity of 16.5 km/s.
In its orbital architecture around PSR B1257+12, PSR B1257+12 d completes one full revolution every 98.211 Earth days at a semi-major axis of 0.46 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 51 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.0264 (ranging from 0.4479 AU at periapsis to 0.4721 AU at apoapsis), the planet experiences minimal orbital distance variation.
ℹ️ Thermal & Atmospheric Regime: Current photometric and spectroscopic constraints for PSR B1257+12 d place it outside the conservative habitable zone definition pending further atmospheric characterization.
The host star PSR B1257+12 is classified as a stellar host with a mass of 1.4 M☉. Stellar evolution modeling indicates an estimated stellar age of 3 Gyr. The PSR B1257+12 system is a multi-planet architecture hosting 3 confirmed worlds, with PSR B1257+12 d sharing its stellar neighborhood alongside PSR B1257+12 b, PSR B1257+12 c.
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: Arecibo Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | PSR B1257+12 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | — |
| Stellar Radius | — |
| Stellar Mass | 1.4000 M☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | 3.000 Gyr |
| Apparent Magnitude | — |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.460000 AU |
| Orbital Period | 98.211 days |
| Mean Orbital Velocity | 51 km/s |
| Orbital Eccentricity (e) | 0.02640 |
| Orbital Inclination (i) | 47.0000° |
| Mean Bulk Density | 3.69 g/cm³ (16.5 km/s vesc) |
| Insolation Flux | — |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1956.900 LY (600.000 pc) |