Gliese 832
A nearby red dwarf with one confirmed Jupiter-like planet.
Gliese 832 (also cataloged as Gl 832 or GJ 832) is a red dwarf star with the spectral classification M2V, situated in the southern constellation Grus. Its apparent visual magnitude of 8.66 makes it invisible without a telescope. The star lies relatively close to our solar system, at a distance of 16.2 light-years, and moves across the sky at a high proper motion of 818.16 milliarcseconds per year. It has just under half the mass and radius of the Sun, a rotation period of about 46 days, and an estimated age of roughly 6 billion years. About 52,920 years ago, it reached its closest approach to the Sun, coming within an estimated 15.71 light-years.
Gliese 832 emits X-rays and experiences strong flare activity, but on average produces less ionizing radiation than the Sun. Only at very short radiation wavelengths (below 50 nanometers) does its output exceed that of the quiet Sun, though it never reaches the levels of the active Sun.
The star hosts one confirmed planet, Gliese 832 b, with a second proposed planet having been ruled out in 2022. As of 2024, no additional planets have been found.
Gliese 832 b is a Jupiter-like planet announced in September 2008. It follows a long-period, near-circular orbit and has a false alarm probability of just 0.05%. The planet induces an astrometric perturbation on its star of at least 0.95 milliarcseconds, making it a good target for astrometric detection. Despite its relatively large angular separation from the star, direct imaging is difficult due to the contrast between star and planet. Two studies in 2023 and one in 2025 detected the planet astrometrically, determining two plausible orbital inclinations and revealing a true mass close to that of Jupiter.
Gliese 832 c was initially reported as a second planet, thought to be a super-Earth with a minimum mass about five times that of Earth. It was announced to orbit within the optimistic habitable zone but outside the conservative habitable zone of its star, at a distance that could allow liquid water on its surface. However, a 2015 study raised doubts because its orbital period was close to the star’s rotation period. In 2022, the planet was refuted when a study showed that the radial velocity signal matched stellar activity rather than a planetary origin.
A 2016 study suggested that additional planets could exist in the region between the two previously thought planet
- type
- Red dwarf star
- spectral_type
- M2V
- constellation
- Grus
- distance_from_Sun
- 16.2 light-years
- apparent_magnitude
- 8.66
- mass
- Just under half the Sun's mass
- radius
- Just under half the Sun's radius
Lore & Background
Gliese 832 is a red dwarf star with a relatively leisurely rotation period of 46 days and an estimated age of roughly 6 billion years. It achieved perihelion some 52,920 years ago, coming within an estimated 15.71 light-years of the Sun. The star emits X-rays and, despite strong flare activity, produces on average less ionizing radiation than the Sun, only exceeding quiet Sun levels at extremely short radiation wavelengths below 50 nm.
In September 2008, a Jupiter-like planet designated Gliese 832 b was announced in a long-period, near-circular orbit, with a false alarm probability of 0.05%. Its existence was later confirmed by astrometric observations in 2023 and 2025, revealing a true mass close to that of Jupiter. A second proposed planet, Gliese 832 c, was announced as a super-Earth in the optimistic habitable zone, but doubts were raised in 2015 and its existence was refuted in 2022, with the radial velocity signal attributed to stellar activity.
As of 2024, no additional planets have been found, and Gliese 832 b remains the only known planet in the system. Radial velocity data set an upper limit of 1.5 Earth masses on any undetected planet with a period up to 100 days. A 2012 Herschel study found that if a cometary disc exists, it is not brighter than a fractional dust luminosity of 10⁻⁵.
Reader's Guide
Gliese 832 is significant as a nearby red dwarf star that hosts a confirmed Jupiter-like planet, Gliese 832 b, which was detected astrometrically and has a true mass close to Jupiter's. The system also illustrates the challenges of exoplanet detection, as the proposed super-Earth Gliese 832 c was later refuted due to confusion with stellar activity. The star's proximity and high proper motion make it a valuable target for studying planetary system formation and dynamics around low-mass stars. Its relatively low ionizing radiation output, despite flare activity, provides context for habitability considerations. The system's legacy includes demonstrating the importance of astrometric confirmation for long-period planets and the need to distinguish stellar signals from planetary ones in radial velocity data. As of 2024, it remains a single-planet system with constraints on additional planets, contributing to the broader understanding of planetary architectures around M dwarfs.
Did You Know?
- Gliese 832 achieved perihelion some 52,920 years ago, coming within 15.71 light-years of the Sun.
- The star has a rotation period of 46 days and is roughly 6 billion years old.
- Gliese 832 b was confirmed astrometrically by two 2023 studies and one 2025 study, revealing a true mass close to Jupiter's.
- The proposed planet Gliese 832 c was refuted in 2022 when its radial velocity signal was attributed to stellar activity.
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