AstroSat, India’s first multi-wavelength space-based observatory, has made a groundbreaking discovery. It has detected bright sub-second X-ray bursts from a new and unique neutron star with an ultrahigh magnetic field, otherwise known as a magnetar. This discovery was facilitated by the timing and spectral analysis performed using two onboard instruments of AstroSat: the Large Area X-Ray Proportional Counter (LAXPC) and Soft X-Ray telescope (SXT).
Understanding Magnetars
Magnetars are neutron stars characterized by their ultra-strong magnetic fields, which are much stronger than the Earth’s. The high-energy electromagnetic radiation emitted by these stars results from the decay of their powerful magnetic fields. They demonstrate strong temporal variability, including a slow rotation, rapid spin-down, and bright but short bursts that can last for months.
One such magnetar, SGR J1830-0645, was discovered in October 2020 by NASA’s Swift spacecraft. This magnetar is relatively young at about 24,000 years old and is an isolated neutron star.
What Are Neutron Stars?
A neutron star is a dense and compact stellar object that forms from the remnants of a massive star’s core following a supernova explosion. These stars are some of the densest objects known in the universe, containing an immense mass within a relatively small size. The existence of neutron stars was first suggested by the discovery of pulsars in 1967, which are neutron stars that emit pulses of radiation once per rotation.
The AstroSat Mission
AstroSat is the first dedicated Indian astronomy mission designed to study celestial sources in X-ray, optical, and UV spectral bands simultaneously. The mission was launched in September 2015 aboard PSLV-C30 from the Satish Dhawan Space Centre in Sriharikota. The Mission Operations Center at ISTRAC Bengaluru is responsible for operating AstroSat.
Significant Observations by AstroSat
AstroSat’s major scientific contributions include detecting stars forming in gas streams, offering insights into the behavior of galaxy clusters. It discovered over 75,000 young stars within the Andromeda Galaxy’s bulge, marking a first-of-its-kind discovery. Furthermore, black holes in a binary system were observed spinning almost as fast as possible by the LAXPC and SXT payloads.
UPSC Civil Services Examination: Previous Year Questions (PYQs)
A question in the 2019 UPSC Civil Services Examination asked about the significance of scientists observing the merger of giant ‘blackholes’ billions of light-years away from the Earth. The options given were detection of ‘Higgs boson particles’, detection of ‘Gravitational waves’, confirmation of intergalactic space travel through ‘wormhole’, and understanding ‘singularity’. The correct answer was detection of ‘Gravitational waves’.
This article has demonstrated that AstroSat, India’s first multi-wavelength space observatory, has significantly contributed to our understanding of the universe by detecting notable celestial phenomena, including the existence of magnetars.
Last Modified: February 22, 2024