Gliese 876 is a red dwarf located about 15 light-years from Earth in the Aquarius constellation. It is a main sequence red dwarf that is very cool and dim (M3.5 V). After Gliese 1061, YZ Ceti, Tau Ceti, and Luyten’s Star, it is one of the closest known stars to the Sun confirmed to have a planetary system with more than two planets; as of 2018, four extrasolar planets have been discovered to orbit the star. In comparison to our Sun, Sol, this star may have one-third the mass, 36 to 39 percent of its diameter, and slightly more than a thousandth (around 0.0016) of its visual luminosity.
Gliese 876 is a star system in the Aquarius Constellation’s UPP Sector of the Outer Veil. The orbital properties of the planets are also noteworthy in the planetary system. It is the only known system of orbital companions to exhibit a near-triple conjunction, a rare phenomenon known as Laplace resonance. The system is made up of the same-named red dwarf, which is located approximately 15.30 light-years (4.69 parsecs) Coreward-Spinward from the Sol System. It is also the first extrasolar system with measured coplanarity around a normal star. Planets b and c, which are located in the system’s habitable zone, are giant planets thought to be analogous to Jupiter.
Distance and visibility
Gliese 876 is a relatively close neighbor to the Solar System. According to Hipparcos satellite astrometric measurements, the star has a parallax of 213.28 milliarcseconds, corresponding to a distance of 4.69 parsecs (15.3 ly). Despite its proximity to Earth, the star is so dim that it is invisible to the naked eye and can only be seen through a telescope.
Gliese 876 also has an inner planet with a mass half that of Jupiter, according to previous ground-based observations. The system’s inner gas planet appears as a bright star-like object close to the red dwarf. Despite its close proximity to Earth, the red dwarf star is only one-third the mass of our Sun and cannot be seen with the naked eye.
Stellar characteristics
Gliese 876 is a red dwarf that has a planet about twice the mass of Jupiter orbiting it. Gliese 876, as a red dwarf, is much less massive than the Sun: estimates suggest it has only 32% of the Sun’s mass. Gliese 876’s surface temperature is lower than that of the Sun, and the star has a smaller radius. These factors combine to make the star only 1.24 percent as bright as the Sun, with the majority of this occurring at infrared wavelengths.
The formation of diatomic molecules in cool stars’ atmospheres makes the spectrum extremely complex, making estimating their age and metallicity difficult. It is estimated that Gliese 876 has a slightly lower abundance of heavy elements than the Sun based on fitting the observed spectrum to model spectra (around 75 percent the solar abundance of iron). The relatively high eccentricity of the planet’s orbit serves as another reminder that our own solar system is not always representative of planetary systems in general.
The star’s age is estimated to be between 6.5 and 9.9 billion years old based on chromospheric activity, depending on the theoretical model used. However, its membership in the young disk population suggests that the star is less than 5 billion years old, but the star’s long rotational period suggests that it is at least 100 million years old. Gliese 876, like many low-mass stars, is a variable star. It has the variable star designation IL Aquarii and is a BY Draconis variable. Its brightness varies by about 0.04 magnitudes. Large starspots moving in and out of view as the star rotates are thought to cause this type of variability. Gliese 876 emits X-rays in the same way that most Red Dwarfs do.
