Astronomers Confirm Third Super-Earth Orbiting Orange Dwarf HD 176986

In February 2026, an international coalition of researchers announced the discovery of a third exoplanet within the planetary system of the orange dwarf HD 176986, officially designated as HD 176986 d. This stellar neighborhood was already recognized for hosting two "super-Earth" class planets, making the new find a significant addition to the system's known architecture. The comprehensive details of this celestial discovery were formally released on January 28, 2026, by a dedicated group of scientists operating out of the Teide Observatory, located in the Canary Islands, Spain.

To achieve this breakthrough, researchers utilized the high-precision HARPS and HARPS-N spectrographs as part of the Rocky Planets in Equatorial Stars (RoPES) initiative. The HARPS-N instrument is integrated into the 3.58-meter Telescopio Nazionale Galileo at the Roque de los Muchachos Observatory, serving as the northern counterpart to the original HARPS instrument located at the 3.6-meter ESO telescope in La Silla, Chile. The Teide Observatory, which is overseen by the Instituto de Astrofísica de Canarias, remains one of the world's premier locations for advanced astronomical observation and deep-space research.

Situated approximately 91 light-years from Earth, the HD 176986 system centers around a K2.5V spectral class star. This orange dwarf is notably smaller and less massive than our Sun, possessing roughly 79% of the solar mass and an estimated age of 4.3 billion years. With an effective surface temperature of 4931 Kelvin, stars of this K-type are particularly intriguing to astrobiologists. They emit significantly less harmful ionizing radiation than G-type stars like our Sun and enjoy a much longer lifespan on the main sequence, providing a stable environment for potential planetary development and the study of rocky worlds.

The newly identified planet, HD 176986 d, is categorized as a super-Earth with a calculated minimum mass approximately 6.76 times that of Earth. It completes a full orbit around its host star every 61.38 Earth days at an orbital distance of 0.28 astronomical units (AU). Scientists have estimated its equilibrium temperature to be around 90°C (363 Kelvin). While this temperature makes HD 176986 d too hot to be considered a primary candidate for habitability, the entire system functions as a vital astrophysical laboratory for understanding how planets form and evolve outside our solar system.

The research also provided refined characteristics for the two previously known planets in the system. HD 176986 b features a short orbital period of 6.49 days, a minimum mass of 5.36 Earth masses, and a scorching equilibrium temperature of 694°C (767 K). Meanwhile, the more massive HD 176986 c orbits every 16.81 days with a minimum mass of at least 9.75 Earth masses and a temperature of 285°C (558 K). This breakthrough was made possible by an extensive data set spanning 330 nights of observation over more than 18 years, allowing astronomers to pinpoint planets with longer orbital periods and providing essential comparative data for the evolution of planets around low-mass stars.