LP 890-9 b
Astrophysical Synthesis & Habitability Characterization
LP 890-9 b is a confirmed super-earth exoplanet orbiting the star LP 890-9, located approximately 105.8 light-years (32.43 parsecs) from the Solar System. First announced in 2022 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.6049% across the stellar disk), this world measures 1.32 Earth radii and has a measured mass of 13.2 Earth masses. Combining its mass and radius yields a mean bulk density of 31.65 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 7.58 g⊕ (74.33 m/s²), and an escape velocity of 35.4 km/s.
In its orbital architecture around LP 890-9, LP 890-9 b completes one full revolution every 2.73 Earth days at a semi-major axis of 0.01875 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 74.7 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 396 K (+123°C / +253°F) and receiving 4.09 S⊕ (~5,566 W/m²), LP 890-9 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star LP 890-9 is classified as a low-mass red dwarf of spectral type M6 V with an effective photospheric temperature of 2,850 K, a radius of 0.1556 R☉, a mass of 0.118 M☉, an estimated bolometric luminosity of 0.00143 L☉. Stellar evolution modeling indicates an estimated stellar age of 7.2 Gyr and a metallicity of [Fe/H] = -0.028 dex (near-solar heavy-element abundance). From Earth, LP 890-9 shines at apparent V-band magnitude 18 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere. The LP 890-9 system is a multi-planet architecture hosting 2 confirmed worlds, with LP 890-9 b sharing its stellar neighborhood alongside LP 890-9 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: Transiting Exoplanet Survey Satellite (TESS) · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | LP 890-9 |
| Spectral Type | M6 V |
| Effective Temp (Teff) | 2,850 K |
| Stellar Radius | 0.1556 R☉ |
| Stellar Mass | 0.1180 M☉ |
| Bolometric Luminosity | 0.00143 L☉ |
| Metallicity [Fe/H] | -0.028 dex |
| Stellar Age | 7.200 Gyr |
| Apparent Magnitude | V: 18.000 · G: 15.821 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.018750 AU |
| Orbital Period | 2.73 days |
| Mean Orbital Velocity | 74.7 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 89.6700° |
| Mean Bulk Density | 31.65 g/cm³ (35.4 km/s vesc) |
| Insolation Flux | 4.0900 S⊕ (~5,566 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 105.800 LY (32.430 pc) |