All posts tagged: Cosmology

Student astronomer discovers rare white dwarf star feeding on a red dwarf companion

Student astronomer discovers rare white dwarf star feeding on a red dwarf companion

Published by Jenni Sidey

ASKAP J1745-5051 did not look like an easy answer to anything. It flashed radio waves every 1.4 hours, then went quiet for stretches. Then it lit up again with a pattern astronomers had trouble classifying. That odd behavior has now helped pin down one of astronomy’s stranger new mysteries. In a study published in Nature Astronomy, an international team reports that ASKAP J1745-5051 is a compact binary system. In this system, a white dwarf is pulling material from a low-mass red dwarf companion. The finding offers some of the strongest evidence yet that at least some long-period radio transients come from white dwarf binaries. Previously, many had suspected they came from slowly spinning neutron stars. The system was first spotted in an untargeted search for circularly polarized radio sources with the Australian Square Kilometre Array Pathfinder, or ASKAP. Additionally, follow-up observations with MeerKAT sharpened its position. Astronomers matched it to a faint optical source in Gaia data. What they found next changed the story. Artist’s impression of the white dwarf binary ASKAP J1745-5051. The smaller, …

Deep-space water reservoir contains trillions of times more water than all Earth’s oceans combined

Deep-space water reservoir contains trillions of times more water than all Earth’s oceans combined

Published by Jenni Sidey

A cloud of water larger than anything ever seen in space has turned up around one of the brightest objects in the early universe. The reservoir surrounds the quasar APM 08279+5255, a blazing source powered by a supermassive black hole more than 12 billion light-years from Earth. The scale is hard to grasp. Astronomers estimated that the water there equals about 140 trillion times the volume of Earth’s oceans. It is also the most distant water reservoir ever detected, placing it in a period when the universe was far younger than it is today. That alone made the finding unusual. What made it more revealing was the setting. The water is not sitting quietly in a cold cloud. It exists in a harsh, energized region around a black hole with a mass about 20 billion times that of the sun. The quasar’s total energy output matches roughly a thousand trillion suns, flooding nearby gas with radiation. “The environment around this quasar is very unique in that it’s producing this huge mass of water,” said Matt …

New analysis reveals why Ganymede has a magnetic field when other moons do not

New analysis reveals why Ganymede has a magnetic field when other moons do not

Published by Jenni Sidey

Ganymede has long looked like a contradiction in orbit. Jupiter’s largest moon is the only moon known to generate its own magnetic field, a trait more commonly associated with planets like Earth and Mercury. But that magnetic shield points to a liquid, churning metal core, and by many formation models, Ganymede should have started out too cold to build one. A new analysis argues that both ideas may be true, at least in part. Instead of forming a metallic core near the beginning of the solar system and slowly cooling ever since, Ganymede may have begun cold and then warmed over billions of years. In that picture, metal inside the moon melted late, sank inward, and may still be feeding the core today. The result is a different kind of dynamo, the deep planetary engine that creates magnetic fields. Possible thermal evolution of Ganymede’s interior based on assumed initial temperatures. (CREDIT: Science Advances) “For decades, studies have progressed in parallel with conflicting assumptions about how Ganymede formed and evolved,” Kevin Trinh lead author from Arizona …

Mars’ atmosphere is changing how scientists see unmagnetized planets

Mars’ atmosphere is changing how scientists see unmagnetized planets

Published by Jenni Sidey

Mars does not have Earth’s kind of magnetic shield, so it has often been treated as the solar system’s more exposed world. It is a planet left to take the sun’s blows with far less protection. But during a violent solar storm in December 2023, NASA’s MAVEN spacecraft caught Mars doing something scientists did not expect to see so clearly. Instead, it appeared to shove plasma aside inside its own atmosphere. The observations offer the first direct evidence that a process called the Zwan-Wolf effect can happen within the ionosphere of an unmagnetized planet. Until now, that effect had largely been associated with places such as Earth’s magnetosphere. This is where a strong internal magnetic field helps redirect the solar wind before it can plunge too deeply toward the planet. The new work, led by West Virginia University planetary scientist Christopher Fowler, shows that Mars can produce a similar response even without a global dipole magnetic field. Therefore, the finding broadens the picture of how space weather shapes worlds across the solar system, including Venus, …

Astronomers can now measure newborn planet mass from dusty stellar rings

Astronomers can now measure newborn planet mass from dusty stellar rings

Published by Jenni Sidey

A bright ring of dust circling a young star can look calm from far away. In reality, it may mark one of the messiest moments in planetary birth, where gas, pebbles, and gravity are still fighting over what kind of solar system will emerge. These disks, the swirling bands of gas and dust around young stars, are where planets form. Modern observatories such as the Atacama Large Millimeter/submillimeter Array, or ALMA, have revealed that many of them contain sharply defined rings and gaps. Astronomers have long suspected that some of those structures are the work of hidden planets, but turning those patterns into reliable planet measurements has remained difficult. “These bright rings are not just beautiful structures – they are essentially planetary fingerprints,” said lead author Amena Faruqi, a PhD student in the Astronomy and Astrophysics Group at the University of Warwick. Simulation of a planet embedded in a protoplanetary disc, causing disc material to pile up in a ring exterior to its orbit. (CREDIT: Amena Faruqi / University of Warwick) “We’ve long understood that …

Forty years of solar data finds our Sun is changing from the inside out

Forty years of solar data finds our Sun is changing from the inside out

Published by Jenni Sidey

The Sun’s 11-year cycle still drives flares, aurorae, and geomagnetic storms, but the machinery under that familiar rhythm may be changing in a deeper way. After tracking sound waves inside the Sun for nearly four decades, researchers say its magnetic activity now appears to be packed into a thinner layer just below the visible surface. That matters because the solar cycle is the engine behind the space weather that can interfere with satellites, GPS, communications, and power grids on Earth. The new analysis, published in Monthly Notices of the Royal Astronomical Society, used observations from the Birmingham Solar Oscillations Network, or BiSON, a set of six telescopes around the world that has monitored the Sun since the late 1980s. Instead of focusing only on sunspots or radio emissions, the team listened to the Sun’s internal oscillations, tiny pressure waves known as p modes, to see how the star’s interior has changed from solar cycle 22 through cycle 25. Professor Bill Chaplin of the University of Birmingham, the study’s lead author, said: “The Sun has its …

Astronomers observe six red dwarf stars ‘eating’ Earth-like planets

Astronomers observe six red dwarf stars ‘eating’ Earth-like planets

Published by Jenni Sidey

A young red dwarf can look calm from a distance. But buried in its light may be the chemical remains of a wrecked world. That is the picture emerging from a new analysis of stars in open clusters, where astronomers found some of the clearest evidence yet that certain young stars may swallow nearby rocky planets. The clue is lithium, a fragile element that should vanish early in these small stars, yet in a handful of cases is still sitting in plain view. The stars in question are red dwarfs, the smallest and coolest stars in the universe, and by far the most common. They are dim compared with the Sun, but their interiors run hot enough to destroy lithium soon after they form. That makes any later detection of lithium stand out sharply. “We found that a few of the red dwarf stars we studied contained lithium, a chemical element that should not be there,” lead author Professor Robin Jeffries of Keele University said. “Therefore even a small amount of lithium stands out clearly …

Mercury’s polar water ice may have arrived in one giant impact

Mercury’s polar water ice may have arrived in one giant impact

Published by Jenni Sidey

Mercury’s water ice has always looked like a contradiction. By day, the planet’s surface can soar to about 430 degrees Celsius, hot enough to destroy the idea of stable surface water almost on contact. Mercury also lacks a true atmosphere, leaving it with only a fragile exosphere. This exosphere offers little protection. Yet near its poles, inside craters that never see sunlight, water ice appears to persist. The puzzle has never been whether the cold traps can hold ice. It has been how the ice got there. Additionally, it is why it seems so concentrated. A new modeling study points to a dramatic answer. Instead of building up slowly over immense spans of time, much of Mercury’s polar water may have been delivered in one major impact event. It may have been redistributed across the planet within a single Mercurian solar day. That day is equal to 176 Earth days. That idea is not entirely new. However, what sets this work apart is that the team fully modeled the aftermath of a large Hokusai-like impact. …

The Universe is creating black holes in many different ways

The Universe is creating black holes in many different ways

Published by Jenni Sidey

When black holes collide, they do not all seem to follow the same cosmic script. A sweeping new analysis of the latest gravitational-wave catalog suggests the universe is producing merging black hole pairs through several distinct channels, not one. Some of those systems appear to come from ordinary stellar evolution, while others carry signs of stranger histories, including black holes that may already be the remnants of earlier mergers. The study draws on GWTC-5.0, the newest release from the LIGO-Virgo-KAGRA Collaboration, which includes data through the second part of the fourth observing run. In the population analysis, researchers examined 267 compact binary merger candidates, up from 161 in the previous catalog update. Of those, 259 were classified as binary black hole candidates for black-hole-only population studies. That expanding sample is changing the field’s focus. Instead of treating each signal as a one-off curiosity, researchers can now look for patterns across the population. This newest version of the “Masses in the Stellar Graveyard” plot compares the numbers and masses of black holes and neutron stars discovered …

JWST catches mineral clouds forming and fading on ‘hot Jupiter’ exoplanet

JWST catches mineral clouds forming and fading on ‘hot Jupiter’ exoplanet

Published by Jenni Sidey

WASP-94A b, a hot Jupiter nearly 700 light-years away, builds mineral cloud cover each morning and loses it by evening. This gives astronomers a rare clear view of its atmosphere and shows how cloud cycles can distort what distant worlds seem made of. WASP-94A b spends each day under a strange routine. By morning, one side of the giant planet is wrapped in mineral clouds. By evening, those clouds are gone, burned off or dragged downward. This leaves a clearer view into an atmosphere that had long been blurred by haze-like interference. That daily turnover, detected with the James Webb Space Telescope, gives astronomers one of their sharpest looks yet at how weather works on a hot Jupiter. This is the class of gas giant that orbits perilously close to its star. In addition, it fixes a major problem that had been skewing estimates of what this planet is actually made of. The work, published in Science, focused on WASP-94A b, a gas giant in the constellation Microscopium, nearly 700 light-years from Earth. Researchers found …