Description

Copyright infringement not intended

Picture Courtesy: MSN.COM

Context:

Durham University physicists have discovered stars located in the Dragon Arc galaxy.

About the recent discovery

Physicists at Durham University have identified over 44 previously unknown stars located in a galaxy called Dragon Arc, which is nearly 6.5 billion light-years away.

This is the first time such a large number of individual stars has been discovered at such a distant range.

How were these stars discovered?

The stars were discovered using images captured by the James Webb Space Telescope (JWST).

The images were magnified by a scientific phenomenon called gravitational lensing, which allowed scientists to observe the stars hidden behind Abell 370; a cluster of galaxies located nearly 5 billion light-years away from the Earth in the constellation Cetus.

James Webb Space Telescope (JWST)

Purpose: It is a NASA space observatory that studies the history of the universe, including the formation of stars, galaxies, and planetary systems. It is designed to complement the Hubble and Spitzer space telescopes by observing near- and mid-infrared wavelengths with greater resolution and sensitivity.

Size: JWST is the largest and most complex observatory ever sent into space. It's the size of a tennis court and three stories high.

Mirrors: JWST has four mirrors, including a primary mirror with 18 hexagonal segments that are each 4.3 feet in diameter. The mirror segments are made of beryllium and coated in gold.

Sunshield: JWST has a large sunshield to keep the telescope cold and prevent unwanted infrared light from interfering with observations.

Orbit: JWST orbits the sun at the second Lagrange point (L2), which is 1.5 million kilometers from Earth. This location is useful because it's a gravity well, so less fuel is needed to keep the telescope there. L2 also follows Earth around the sun, which allows for communication and image downloads.

Launch: JWST launched on December 25, 2021 from Kourou, French Guiana. It arrived at its destination in January 2022.

Gravitational Lensing

It is a phenomenon that occurs when a massive object, like a galaxy cluster or black hole, bends light from a more distant object, creating a distorted image.

Gravity is the curvature of spacetime, and massive objects cause spacetime to curve. When light passes through this curved spacetime, it bends, similar to how light passes through a lens.

The distorted image can be a ring or halo of light around the gravitational lens. The image can also be magnified, allowing astronomers to see objects that would otherwise be too far away.

In this case, the Abell 370 galaxy cluster stretched and magnified the light from the Dragon Arc galaxy, revealing the hidden stars.

What makes the stars in the Dragon Arc galaxy special?

The stars discovered are red supergiants, which are hard to observe because they are surrounded by dust that hides them from standard instruments. These stars were formed during "cosmic noon," a period when the universe experienced a peak in star formation.

Must Read Articles:

JAMES WEBB TELESCOPE

Source:

Indian Express

PRACTICE QUESTION

Q.Which one of the following is correct about the “Cosmic noon”:

A) The time when the first stars formed in the universe.

B) The time when the Milky Way galaxy was formed.

C) The period when the universe was dominated by dark energy.

D) The period when star formation was at its peak.

Answer: D

Explanation:

Cosmic noon was a period in the history of the universe when star formation was at its peak, and black holes and galaxies were merging frequently. It occurred about 2–3 billion years after the Big Bang.