About C/2023 A3|| Tsuchinshan–ATLAS|| UPSC Current Affairs

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Context

C/2023 A3 (Tsuchinshan–ATLAS) comet will pass perihelion at a distance of 0.39 AU on 27 September 2024, when it could become visible to the naked eye.

Comet C/2023 A3

Also known as Tsuchinshan–ATLAS, it is a long-period comet from the Oort Cloud, discovered independently by two observatories, the Purple Mountain Observatory on 9 January 2023 and the ATLAS project (Asteroid Terrestrial-impact Last Alert System) on 22 February 2023.

Purple Mountain Observatory

The Purple Mountain Observatory, also known as Zijinshan Astronomical Observatory is an astronomical observatory located on the Purple Mountain in the east of Nanjing province, China.

ATLAS

The Asteroid Terrestrial-impact Last Alert System (ATLAS) is a robotic astronomical survey and early warning system optimized for detecting smaller near-Earth objects a few weeks to days before they impact Earth. Funded by NASA, and developed and operated by the University of Hawaii's Institute for Astronomy, the system currently has four 0.5-meter telescopes.

Oort Cloud

The Oort Cloud lies far beyond Pluto and the most distant edges of the Kuiper Belt. While the planets of our solar system orbit in a flat plane, the Oort Cloud is believed to be a giant spherical shell surrounding the Sun, planets and Kuiper Belt Objects. It's like a big, thick bubble around our solar system, made of icy, comet-like objects. The Oort Cloud's icy bodies can be as large as mountains – and sometimes larger.

Read about Kuiper belt: https://www.iasgyan.in/daily-current-affairs/kuiper-belt#:~:text=The%20Kuiper%20Belt%20is%20located,Neptune%20that%20contains%20icy%20objects.

NEO

A near-Earth object (NEO) is an asteroid or comet whose trajectory brings it to within 1.3 astronomical units of the Sun and hence within 0.3 astronomical units, or approximately 45 million kilometres, of the Earth’s orbit

Comparison of comets, asteroids, meteoroids, meteors, and meteorites

Feature	Comet	Asteroid	Meteoroid	Meteor	Meteorite
*Definition*	A small Solar System body made of ice, dust, and rock. When close to the Sun, comets display a visible coma or tail.	Rocky, airless remnants left over from the formation of the Solar System, mostly found in the asteroid belt.	Small rocky or metallic bodies in space, smaller than asteroids.	A meteoroid that enters the Earth's atmosphere and burns up, causing a streak of light.	A piece of a meteoroid that survives the atmospheric entry and impacts Earth’s surface.
*Composition*	Primarily ice, dust, and frozen gases with some organic compounds.	Mainly composed of rock and metals, particularly silicates and nickel-iron.	Composed of rock or metal, typically fragments of asteroids or comets.	The same as meteoroids, but observed as a streak of light due to atmospheric friction.	Similar composition to meteoroids, typically rock or metal.
*Location*	Originate from the Oort Cloud or Kuiper Belt at the edge of the Solar System.	Mostly found in the Asteroid Belt between Mars and Jupiter.	Can be found anywhere in the Solar System, drifting through space.	Found only when entering Earth's atmosphere.	Found on Earth’s surface after impact.
*Visibility*	Visible when they come near the Sun and develop a coma and tail.	Not visible to the naked eye unless large enough and observed with a telescope.	Generally not visible until they enter Earth’s atmosphere (becoming meteors).	Visible as bright streaks of light in the sky, often called "shooting stars".	Not visible unless discovered on the ground post-impact.
*Tail*	Develops a long, glowing tail (plasma and dust) when near the Sun, pointing away from the Sun due to solar wind.	No tail.	No tail.	Appears as a streak of light caused by the object's high-speed entry into the atmosphere.	No tail.
*Size*	Can range from a few hundred meters to tens of kilometers in diameter.	Can range from meters to hundreds of kilometers in diameter.	Typically less than 1 meter in size.	Varies, depending on the size of the meteoroid (usually very small).	Can vary in size from small pebbles to large boulders.
*Orbit*	Often have highly elliptical orbits that bring them close to and far from the Sun.	Most asteroids have circular orbits within the asteroid belt, but some can have more eccentric orbits.	Do not have specific orbits, as they are small fragments.	No fixed orbit, as they are transient in Earth’s atmosphere.	No orbit once on Earth's surface.
*Origin*	Believed to come from the Oort Cloud or Kuiper Belt, far beyond Neptune.	Mostly originate in the Asteroid Belt between Mars and Jupiter.	Often fragments from comets or asteroids.	Derived from meteoroids that enter Earth’s atmosphere.	Derived from meteoroids that survive atmospheric entry and land on Earth.
*Examples*	Halley’s Comet, Comet Neowise	Ceres, Vesta, Pallas	Fragments from comets or asteroids	Perseid meteors, Geminid meteors	The Hoba meteorite, Allende meteorite

Sources:

NDTV

PRACTICE QUESTION

Q:Consider the following statements in reference to Oort Cloud:

1. Oort Cloud is a spherical shell of icy objects surrounding the solar system and its existence has been confirmed through direct observations of its constituent objects.

2. Comets originating from the Oort Cloud are often referred to as long-period comets.

Select the correct statements using the codes given below:

a) 1 only

b) 2 only

c) Both 1 and 2

d) Neither 1 nor 2

Answer: b

Explanation:

Statement 1 is incorrect: While the Oort Cloud is theorized to exist based on observations of long-period comets, it has not been directly observed due to its extreme distance from the Sun and the faintness of its objects. The distance range is also highly uncertain, and 200,000 AU is an upper estimate.

Statement 2 is correct: Long-period comets are thought to originate from the Oort Cloud, and they can have highly elliptical orbits with periods longer than 200 years. Their paths are not confined to the ecliptic plane, and they can come from any direction, making their inclinations highly varied.

C/2023 A3 (TSUCHINSHAN–ATLAS)