Unique Ring found around a Dwarf Planet

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• Astronomers discover a ring around the dwarf planet Quaoar in the Kuiper Belt.

About

• In a recent study done by Bruno Morgado of the Federal University of Rio de Janeiro and Bruno Sicardy of the Paris Observatory, a ring was founded positioned much further away from the planet than is usual.
• The ring lies far away from the Roche limit, a mathematically determined distance beyond which rings aren’t supposed to exist.
• The finding defies theoretical explanations and may force astronomers to rethink the laws governing planetary rings.
• With an estimated radius of 555 km, Quaoar is roughly half the size of Pluto and orbits beyond Neptune.
• The dwarf planet passed in front of four stars, allowing researchers to observe the shadow of the eclipses and the dimming of the starlight before and after the star blinked out, indicating a ring obscuring part of the light

How was the ring discovered?

• Researchers detected the ring using a phenomenon called stellar occultation, which occurs when a bright star passes behind a planet.
• Quaoar is located about 4 billion miles from the Sun and is roughly half the size of Pluto.
• It has a moon called Weywot and is too small and distant to be observed directly.
• Quaoar was observed for three years (2018-2021) using Earth-based and space-based telescopes

What is the Roche limit?

• It is the mathematically determined distance beyond which rings around a celestial body are not supposed to exist.
• It is named after Édouard Roche, a French astronomer who discovered the limit in 1848.
• The Roche limit is applicable to any planet and the celestial bodies around it
• It is the minimum distance at which a celestial body disintegrates and turns into a ring.

What is the Kuiper Belt?

• It is a region in the outer solar system beyond the orbit of Neptune that is home to many small, icy objects.
• It is named after Gerard Kuiper, who first proposed the existence of this region in 1951.
• The Kuiper Belt is believed to be the source of many comets that periodically enter the inner solar system.
• Some of the most famous objects in the Kuiper Belt include Pluto, Eris, Haumea, Makemake, and several others.
• The study of the Kuiper Belt and its objects provides valuable information about the early history and formation of the solar system.

Why is Quaoar’s ring unusual?

• The ring is located 2,500 miles away from Quaoar, which is 1,400 miles further away from the Roche limit than expected.
• According to the researchers, particles of the ring should have come together to form a moon at such a distance.
• The distance between Quaoar and its ring raises questions about how the ring has managed to remain stable.

Possible explanations for Quaoar’s far-out ring

• The researchers suggest that Quaoar’s moon, Weywot, or some other unseen moon contributes gravity that somehow holds the ring stable
• Another potential explanation is that the particles of the ring are colliding with each other in such a way that they are avoiding coalescing into a moon.

Way Ahead

• The discovery of Quaoar’s ring raises the possibility of discovering more rings around smaller planets in the outer solar system
• The findings may prompt a rethinking of planetary ring laws and expand our understanding of planetary ring systems

Source: IE