Mu2 Scorpii b
A directly imaged substellar companion to Mu2 Scorpii.
Last updated
Mu2 Scorpii b is a substellar object orbiting the star Mu2 Scorpii, located about 474 light-years from the Sun in the constellation Scorpius. It was discovered in 2022 via direct imaging and is classified as either a super-Jupiter or a brown dwarf, lying slightly above the deuterium burning limit.
Quick Facts
- Discovery method
- Direct imaging
- Discovery year
- 2022
- Host star
- Mu2 Scorpii (Pipirima)
- Distance
- 474 light-years
- Classification
- Super-Jupiter or brown dwarf
- Status
- Confirmed planet or brown dwarf
Facts from the source article.
Lore & Background
Mu2 Scorpii b was identified in 2022 as one of two substellar objects found around the star Mu2 Scorpii via direct imaging. It is the outer of the two, with an inner candidate also detected.
The object is described as being slightly above the deuterium burning limit, placing it at the boundary between a massive planet and a brown dwarf. The host star, Mu2 Scorpii, is a blue-white B-type subgiant with a mass 9.1 times that of the Sun and a luminosity 2,385 times solar, making it a supernova progenitor. The star is approximately 20 million years old and belongs to the Upper Centaurus–Lupus subgroup of the Scorpius–Centaurus association.
Reader's Guide
Mu2 Scorpii b is notable as one of the few substellar objects discovered through direct imaging, a technique that captures light from the companion itself rather than inferring its presence through stellar wobble or transits. Its discovery around a massive, young B-type star adds to the understanding of planet and brown dwarf formation in high-mass stellar environments. The object's mass, near the deuterium burning limit, makes it a key example for studying the boundary between planets and brown dwarfs.
As part of a system with a second candidate, it also offers a rare opportunity to examine multiple substellar companions around a single star. The star's membership in the Scorpius–Centaurus association provides context for the age and environment of the system. Mu2 Scorpii b's detection in 2022 contributes to the growing census of directly imaged exoplanets and brown dwarfs, which are critical for testing models of atmospheric and orbital evolution.
Frequently Asked Questions
What is Mu2 Scorpii b?
It is a substellar companion orbiting the star Mu2 Scorpii (Pipirima), located roughly 474 light-years away in the constellation Scorpius. Whether it qualifies as a super-Jupiter or a brown dwarf is still debated because its mass sits just above the deuterium-burning threshold.
Is Mu2 Scorpii b a planet or a brown dwarf?
It falls slightly above the deuterium-burning limit, so catalogues variously label it a confirmed super-Jupiter or a brown dwarf depending on which mass boundary is applied.
More in Exoplanets Found by Imaging and Microlensing
Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Mu2 Scorpii (CC BY-SA 4.0).
- Word definitions: the Codexery glossary, each quoted from its Wikipedia article.
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