DMPP-9 b

Astrophysical Synthesis & Habitability Characterization

DMPP-9 b is a confirmed sub-neptune exoplanet orbiting the star DMPP-9, located approximately 357.3 light-years (109.54 parsecs) from the Solar System. First announced in 2026 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 3.89 Earth radii (0.35 Jupiter radii) and has a measured mass of 14.43 Earth masses. Combining its mass and radius yields a mean bulk density of 1.35 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.95 g⊕ (9.32 m/s²), and an escape velocity of 21.5 km/s.

In its orbital architecture around DMPP-9, DMPP-9 b completes one full revolution every 12.733 Earth days at a semi-major axis of 0.1097 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 93.7 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.25, swinging from 0.0823 AU at periapsis out to 0.1371 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.

⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 996 K (+723°C / +1333°F) and receiving 176.60 S⊕ (~240,354 W/m²), DMPP-9 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star DMPP-9 is classified as a stellar host with an effective photospheric temperature of 6,092 K, a radius of 1.26 R☉, a mass of 1.1 M☉, an estimated bolometric luminosity of 1.962 L☉. From Earth, DMPP-9 shines at apparent V-band magnitude 9.22 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere.

Discovery Facility: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).