Astronomers capture most distant star ever seen
Washington: American astronomers have captured the most distant normal star ever observed, some 9 billion light years from Earth, thanks to a rare cosmic alignment.
The study, published on Monday online in the journal Nature Astronomy, revealed the discovery of a star called Icarus, magnified by gravitational lensing by over 2,000 times, reported Xinhua.
Astronomers routinely study galaxies much farther away, visible because they glow with the brightness of billions of stars. They also managed to study supernova, often brighter than the galaxy in which it sits.
However, for a distance of about 100 million light years, the stars in these galaxies are impossible to make out individually.
But a phenomenon called gravitational lensing, the bending of light by massive galaxy clusters in the line of sight, can magnify the distant universe and make dim, far away objects visible.
The single star was discovered in NASA Hubble Space Telescope images taken in late April of 2016 and as recently as April 2017.
"You can see individual galaxies out there, but this star is at least 100 times farther away than the next individual star we can study, except for supernova explosions," said Patrick Kelly at the University of Minnesota, Twin Cities, the paper's first author.
These observations can provide a rare look at how stars evolve, especially the most luminous ones.
"For the first time ever we're seeing an individual normal star - not a supernova, not a gamma ray burst, but a single stable star - at a distance of nine billion light years," said Alex Filippenko, a professor of astronomy at UC Berkeley and one of many co-authors of the report.
The B-type star Icarus is much larger, more massive, hotter and possibly hundreds of thousands of times intrinsically brighter than our Sun.
According to the researchers, an extended lens, like a galaxy cluster, can only magnify a background object up to 50 times, but smaller objects can magnify much more.
A single star in a foreground lens, if precisely aligned with a background star, can magnify the background star thousands of times.
In this case, a star about the size of our sun briefly passed directly through the line of sight between the distant star Icarus and Hubble, boosting its brightness significantly.
Also, if the alignment was perfect, that single star within the cluster turned the light from the distant star into an "Einstein ring": a halo of light created when light from the distant star bends around all sides of the lensing star.
The ring is too small to discern from this distance, but the effect made the star easily visible by magnifying its apparent brightness.
The astronomers predict that Icarus will be magnified many times over the next decade as cluster stars move around, perhaps increasing its brightness as much as 10,000 times.
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India, US trade team to start three-day talks from Dec 10: Sources
New Delhi (PTI): India and the United States will commence three-day talks on the first phase of their proposed bilateral trade agreement here from December 10, sources said.
The visit is crucial as India and the US are working to finalise the first tranche of the pact.
"The three-day talks will start on December 10. It will conclude on December 12, and it is not a formal round of talks," said one of the sources.
The US team will be led by Deputy United States Trade Representative (USTR) Rick Switzer.
This visit of the US officials marks their second trip since the imposition of a 25 per cent tariff and an additional 25 per cent penalty on Indian goods entering the American market due to the purchase of Russian crude oil.
On September 16, the US officials last visited India.
On September 22, Commerce and Industry Minister Piyush Goyal also led an official delegation to the US for trade talks. Goyal had also visited Washington in May.
While the USA's chief negotiator for the pact is Assistant US Trade Representative for South and Central Asia Brendan Lynch, the Indian side is led by Joint Secretary in the Department of Commerce Darpan Jain.
The talks are also important as Commerce Secretary Rajesh Agrawal has recently stated that India is hopeful of reaching a framework trade deal with the US this year itself, which should address the tariff issue to the benefit of Indian exporters.
While noting that the Bilateral Trade Agreement (BTA) will take time, Agrawal has added that India is engaged in protracted negotiations with the US on a framework trade deal that will address the reciprocal tariff challenge faced by Indian exporters.
India and the US are having two parallel negotiations -- one on a framework trade deal to address tariffs and another on a comprehensive trade deal.
In February, leaders of the two countries directed officials to negotiate an agreement.
It was planned to conclude the first tranche of the pact by the fall of 2025. So far, six rounds of negotiations have been held. The agreement aims to more than double bilateral trade to USD 500 billion by 2030, from the current USD 191 billion.
The US remained India's largest trading partner for the fourth consecutive year in 2024-25, with bilateral trade valued at USD 131.84 billion (USD 86.5 billion exports).
The US accounts for about 18 per cent of India's total goods exports, 6.22 per cent of its imports, and 10.73 per cent of its total merchandise trade.
According to exporters, the agreement is important as India's merchandise exports to the US declined for the second consecutive month in October, falling by 8.58 per cent to USD 6.3 billion due to the hefty tariffs imposed by Washington.
