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New antenna design could help detect faint cosmological signals

This could revolutionise our ability to detect the faint signals of Cosmological Recombination Radiation (CRR)

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Image credit: PIB

In an intriguing development, scientists at the Raman Research Institute (RRI) in Bangalore, India, have developed a novel antenna design that could revolutionise our ability to detect the faint signals of Cosmological Recombination Radiation (CRR).

These signals, which are crucial for understanding the thermal and ionization history of the Universe, have so far remained undetected due to their elusive nature. The newly designed antenna is capable of measuring signals in the 2.5 to 4 Gigahertz (GHz) frequency range, which is optimal for detecting CRR, a signal that is approximately one billion times fainter than the Cosmic Microwave Background (CMB).

As per available sources, the universe is approximately 13.8 billion years old, and in its earliest stages, it was extremely hot and dense. During this time, the Universe was composed of a plasma of free electrons, protons, and light nuclei such as helium and lithium. The radiation coexisting with this matter has been detected today as the CMB, which holds vital information about the early cosmological and astrophysical processes.

One such process, known as the Epoch of Recombination, marks the transition from a fully ionized primordial plasma to mostly neutral hydrogen and helium atoms. This transition emitted photons, creating the Cosmological Recombination Radiation (CRR), which distorts the underlying CMB spectrum. Detecting these faint CRR signals would provide a wealth of information about the Universe’s early ionization and thermal history and could even offer the first experimental measurements of helium abundance before it was synthesized in the cores of stars.

However, detecting CRR is a significant challenge because these signals are extremely weak—about nine orders of magnitude fainter than the CMB. To address this, scientists need highly sensitive instruments that can isolate these signals from the vast cosmic noise surrounding them.

To this end, researchers from RRI, including Mayuri Rao and Keerthipriya Sathish, along with Debdeep Sarkar from the Indian Institute of Science (IISc), have developed an innovative ground-based broadband antenna designed to detect signals as faint as one part in 10,000. Their design is capable of making sky measurements in the 2.5 to 4 GHz range, the frequency band most suitable for CRR detection.

According to Keerthipriya Sathish, the lead author of the study, “For the sky measurements we plan to perform, this broadband antenna offers the highest sensitivity compared to other antennas designed for the same bandwidth. The antenna’s frequency-independent performance across a wide range and its smooth frequency response are features that set it apart from conventional designs.”

The antenna is compact and lightweight, weighing just 150 grams, with a square shape measuring 14 cm by 14 cm.

The proposed antenna is a dual-polarized dipole antenna with a unique four-arm structure shaped like a fantail. This design ensures that the antenna maintains the same radiation pattern across its entire operational bandwidth, with a mere 1% variation in its characteristics. This is crucial for distinguishing spectral distortions from galactic foregrounds. The antenna’s custom design allows it to “stare” at the same patch of sky throughout its full operational range of 1.5 GHz (from 2.5 to 4 GHz), which is key to separating the CRR signals from other cosmic noise.

The antenna is compact and lightweight, weighing just 150 grams, with a square shape measuring 14 cm by 14 cm. It is made using a low-loss dielectric flat substrate on which the antenna is etched in copper, while the bottom features an aluminum ground plate. Between these plates lies a radio-transparent foam layer that houses the antenna’s connectors and receiver base.

With a sensitivity of around 30 millikelvin (mK) across the 2.5-4 GHz frequency range, the antenna is capable of detecting tiny temperature variations in the sky. Even before being scaled to a full array, this antenna design is expected to provide valuable first scientific results when integrated with a custom receiver. One of the anticipated experiments is to study an excess radiation reported at 3.3 GHz, which has been speculated to result from exotic phenomena, including dark matter annihilation. These early tests will help refine the antenna’s performance and guide future design improvements aimed at achieving the sensitivity required for CRR detection.

The researchers plan to deploy an array of these antennas in radio-quiet areas, where radio frequency interference is minimal or absent. The antenna’s design is straightforward and can be easily fabricated using methods similar to those employed in Printed Circuit Board (PCB) manufacturing, ensuring high machining accuracy and consistency for scaling up to multiple-element arrays. The antenna is portable, making it easy to deploy in remote locations for scientific observations.

The team is already looking ahead, planning further improvements to achieve even greater sensitivity, with a long-term goal of detecting CRR signals at sensitivities as low as one part per billion. With this innovative antenna design, the team hopes to make significant strides toward uncovering the secrets of the early Universe and its formation.

EP Staff is the editorial team at EdPublica, an independent media organisation focused on science, education, environment and public policy. The team produces evidence-based news, features, explainers and analysis on issues that shape society and everyday life.

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Space & Physics

A Dead Star Feeds Off Planet Formed From Its Ashes

It adds to a known coterie of planets now found orbiting dead stars, astronomers are busy studying to spot signs of life.

Karthik Vinod

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Screenshot 2026 10 05 164626 e1791233298442
The accretion of material from an evaporating second-generation giant planet accreting on a white dwarf star | Credit: Snehalata Sahu

A planet orbiting once every 4 days around a white dwarf star HS 0209+0832  – about 270 light years in the direction of the constellation Pisces – is steadily losing its atmosphere to its host star. While many stars in solar systems beyond our own often feed on their planets, this particular star feeds on its own ashes.

The gaseous planet HS 0209+0832 b was discovered in 2024, when the Transiting Exoplanet Survey Satellite, a NASA space telescope, found it orbiting the white dwarf star over the course of four days. The new study followed through with detailed observations from TESS data, NASA’s space-based Far Ultraviolet Spectroscopic Explorer, in addition to the ESO’s mountain-based Very Large Telescope, to study the star’s atmosphere and in turn inferring some chemistry occurring in the planet.

In a study published in the journal Nature Astronomy on Monday and funded by NASA, European Research Council, Fundación Occident and the Instituto de Astrofísica de Canarias, an international team of astronomers have reported imprints of niobium, a heavy element, in the atmosphere of a white dwarf star.

Astronomers predict the transiting young planet around the dead star is supplying that niobium back to its host. The sighting is evidence of a “second generation” planet, one of many candidates identified over several years, manifesting in a myriad different ways from spent gas ejected in the wake of stellar deaths.

It adds to a known coterie of planets now found orbiting dead stars, astronomers are busy studying to spot signs of life.

What are white dwarf stars?

White dwarves are an exotic stars, and are all that’s left off giant stars shedding their large gaseous skin in violent deaths. Our sun is destined one day to transform into a white dwarf, but only after swelling in size some five billion years from now to become a red giant when it will eclipse past the earth’s orbit. It would take several million years after that for the red giant sun to shed its gaseous exterior to become a white dwarf.

Planets if any, found orbiting these dead stars may have likely migrated from the new solar system’s outer reaches. All that’s left off the progenitor star’s past are imprints of light metals and other elements on the white dwarf’s atmosphere. Such planets have previously been spotted orbiting pulsars, a kind of neutron star, back in 1992. In fact, its discovery had marked the first ever detection of any planet orbiting a star beyond our sun.

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In five billion years, our sun will evolve to become a red giant star. Credit: Svitlana Leonidivna Malchenko

Sighting niobium

Elements such as niobium don’t typically form in the core of stars like our sun. Chemical production usually limits to elements lighter than or until iron, with its 26 protons and 30 neutrons. Beyond that, slamming an extra proton or neutron will cause those to split, leaving iron to be the last element to be directly forged.

Niobium, with 41 protons and 52 neutrons, is thought to be born after absorbing slow passing neutrons when the red giant star dies to form a white dwarf star. This niobium hitches a ride along with rest of the contents of the red giant star, farther into the outer reaches of the system after the formation of the white dwarf.

These contents could create a new disc of circumstellar material with dust and gas that could condense one day to form new planets. The “second generation” planet found orbiting the white dwarf star from the new study, could have been born this way.

Alternatively, it may have been a planet in the outskirts like Neptune, migrating inwards, and enriching itself with niobium-rich star material.

Either way, the planet got too close to its host star, which is irradiating its newfound niobium-rich atmosphere, stripping it away and devouring it.

While it’s likely not a candidate planet for life as we know it to be found, it’s discovery can help ascertain how such worlds are formed in the aftermath of a star’s various phases of evolution.

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Space & Physics

Artemis Accords Reach 76 Countries: What It Means for India

The Artemis Accords now have 76 signatories. With NASA inviting ISRO to its Moon Base programme, India’s role in lunar exploration is expanding.

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Astronaut holding a lunar rock on the Moon with another astronaut in the background, illustrating future lunar exploration.
Representational image of astronauts collecting lunar samples as international missions prepare for a new era of Moon exploration. Image credit: NASA

The Artemis Accords now have 76 signatories, expanding the international framework around the next phase of lunar exploration. For India, the milestone comes weeks after NASA invited the Indian Space Research Organisation (ISRO) to participate in its planned Moon Base programme.

Albania, Croatia, Côte d’Ivoire and San Marino joined the Accords in September, taking participation to 76 countries. NASA says nearly 40% of the world’s nations are now part of the framework, which sets principles for peaceful, transparent and responsible exploration of the Moon, Mars and beyond.

India became the 27th signatory in June 2023. At the India-US Civil Space Joint Working Group meeting in Bengaluru in August, NASA invited ISRO to participate in its Moon Base programme. The two countries also agreed to advance discussions on open scientific-data sharing under the Accords.

Artemis Accords graphic showing the flags of participating countries, including India, with the Moon in the background.
India is among the 76 countries that have signed the Artemis Accords, a framework for peaceful and responsible exploration of the Moon and beyond. Source: NASA

India’s Moon Base opportunity

The invitation does not specify what India will contribute. NASA has said every Artemis Accords signatory can participate through scientific payloads, technology demonstrations, CubeSats and other capabilities. Any specific Indian contribution would require further agreements.

India, however, is developing its own increasingly ambitious lunar programme. ISRO’s Chandrayaan-4 is planned as a lunar sample-return mission, designed to collect samples from the Moon’s polar region and bring them back to Earth. Chandrayaan-5/LUPEX, being developed with Japan’s JAXA, will study lunar polar volatiles in situ.

These missions could give India experience and scientific capabilities relevant to a future international lunar infrastructure.

ISRO Shaping the Data Conversation

Scientific data could be another area of Indian participation. In May 2026, ISRO led an initial Artemis Accords discussion on advancing open-data practices. NASA subsequently held two workshops focused on making lunar scientific data more accessible, interoperable and reproducible across countries.

That is significant as more lunar missions target the same regions. Shared standards could allow researchers to combine observations from different spacecraft instead of treating each mission’s data separately.

Moon – Space Coperation

India-US space cooperation is also expanding into human spaceflight. ISRO’s 2025–26 annual report records that Indian astronaut Shubhanshu Shukla travelled to the International Space Station in June 2025 as part of the Axiom-4 mission and conducted seven microgravity experiments. ISRO also held discussions with NASA on potential cooperation related to Gaganyaan.

The Artemis relationship therefore sits alongside an existing programme of India-US cooperation, including the NASA-ISRO Synthetic Aperture Radar (NISAR) mission.

What Changes for India?

The significance of the 76-country milestone lies in the network developing around it. The Artemis Accords cover scientific-data sharing, interoperability, non-interference between missions, emergency assistance and protection of historically significant lunar sites. NASA says signatories are now working through technical meetings and workshops to put these principles into practice.

For India, that creates several possible avenues: contributing technology or science to NASA’s Moon Base effort, sharing lunar data, and working with a growing group of countries on standards for increasingly crowded lunar operations. What India’s specific contribution to the Moon Base remains undecided. But with Chandrayaan-4, LUPEX and its human-spaceflight programme advancing alongside deeper NASA cooperation, India is entering the next phase of lunar exploration with its own capabilities already taking shape.

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JWST Finds Water Around a Dying Star Near the Milky Way’s Black Hole

A dying star near the Milky Way’s central black hole is shedding water, gas and dust into one of the galaxy’s most extreme environments.

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JWST infrared view of the densely populated region around the Milky Way’s central black hole, filled with stars, glowing gas and dust.
A dense field of stars, gas and dust surrounds the centre of the Milky Way in this infrared view from the James Webb Space Telescope. The region includes the environment around Sagittarius A* and nearby stars such as IRS 3. Image credit: ESA/Webb, NASA & CSA, F. Peißker, J. Lu, F. Yusef-Zadeh, N. B. Sabha, C. Chan

A dying star nearing the end of its life is shedding material into space just 0.55 light-years from the Milky Way’s central black hole. And somehow, some of that material is holding on. New observations from the James Webb Space Telescope have revealed water and oxygen-rich dust surrounding IRS 3, an evolved star living remarkably close to Sagittarius A*, the supermassive black hole at the heart of our galaxy.

The finding gives astronomers a rare view of what happens when an ordinary stage of stellar evolution unfolds in an anything-but-ordinary neighbourhood.

A Dying Star Beside a Black Hole

IRS 3 is an asymptotic giant branch (AGB) star, a late stage in the life of stars like this one. As such stars age, they swell, cool and lose material through powerful stellar winds. IRS 3 is doing exactly that. Gas and dust are streaming away from the star, creating a large envelope around it.

The star sits only about 0.55 light-years from Sagittarius A*. That may sound distant, but on the scale of the Galactic Centre it is remarkably close. Earth is about 26,000 light-years away from the same black hole.

Multi-panel views zooming from the Milky Way’s centre to dying star IRS 3 and Sagittarius A*, comparing visible and infrared observations including JWST’s detailed view.
A series of observations zooms from the Milky Way’s central region to IRS 3, the dying star located about 0.55 light-years from Sagittarius A*. The JWST infrared view reveals the crowded environment around the star and the Milky Way’s central black hole. Image credit: ESA/Webb, NASA & CSA, F. Peißker, J. Lu, F. Yusef-Zadeh, N. B. Sabha, C. Chan

Around Sagittarius A* is a crowded, energetic environment filled with intense radiation, dense gas and powerful gravitational forces. Astronomers have long wondered how stars manage to evolve and shed material there. IRS 3 is offering an answer.

Webb Finds Water in the Stellar Outflow

NASA‘s James Webb Space Telescope looked at IRS 3 using its Mid-Infrared Instrument, or MIRI. Infrared observations are particularly useful here because the dust surrounding the star glows strongly at these wavelengths.

The observations revealed oxygen-rich dust in the star’s envelope. They also produced the first detection of water in this material. This does not mean Webb found a pool, cloud or droplets of water. The water exists as molecules mixed into the hot gas and dust surrounding the star.

That distinction matters because molecules can be vulnerable in the harsh environment around the Galactic Centre. Radiation can break them apart, while the conditions around a supermassive black hole can affect the material being expelled by nearby stars. Yet water molecules are present around IRS 3.

The Star is Feeding Its Surroundings

IRS 3 is losing material rapidly as it approaches the end of its life. Researchers estimate that the star is shedding roughly the mass of Earth every 18 days. That enormous outflow is important beyond IRS 3 itself.

When evolved stars lose their outer layers, they return material to the space between stars. The gas carries elements produced during the star’s lifetime, while newly formed dust becomes part of the reservoir from which future cosmic structures can emerge. IRS 3 is therefore caught in a familiar cycle of stellar life: a star is dying, but the material it releases can become part of something else.

What makes this case unusual is that the recycling process is happening almost next door to a supermassive black hole.

How Much Can Survive Here?

The observation does not mean that the black hole has little influence on its surroundings. Sagittarius A* still creates an extreme environment, and the researchers are interested precisely because IRS 3 shows that stellar material can persist within it.

“Galactic centres are among the most extreme environments,” said Florian Peißker of the University of Cologne, the study’s lead author to media. With Webb, researchers can now examine the material around stars such as IRS 3 in much greater detail and ask how stellar winds, dust formation and molecular chemistry behave so close to a black hole. The answer emerging from IRS 3 is intriguing: the environment may be extreme, but it does not necessarily shut down the chemistry of a dying star.

For IRS 3, the end of its stellar life is already underway. Its outer layers are drifting away into the Galactic Centre, carrying dust, molecules and the chemical ingredients of future cosmic systems with them. Even in the shadow of the Milky Way’s central black hole, a dying star is still leaving something behind.

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