Three separate astronomical studies have reported findings on a distant neutrino source, a stellar occultation by a metal-rich cloud, and the chemical composition of an exoplanet's atmosphere.
The discoveries were published in Nature Astronomy and other journals, and utilized observatories including the IceCube Neutrino Observatory, the James Clerk Maxwell Telescope (JCMT), the Submillimeter Array (SMA), the Atacama Large Millimeter/submillimeter Array (ALMA), the Gemini North and South telescopes, and the Apache Point Observatory.
Distant Starburst Galaxy Linked to High-Energy Neutrino
A study published in Nature Astronomy identifies the galaxy JCMT0402−0424, nicknamed "Shadow Blaster," as a likely source of the high-energy neutrino event IC 210922A, detected by the IceCube Neutrino Observatory in 2021.
Location and Characteristics
Shadow Blaster is a compact, dusty, star-forming galaxy located approximately 11 billion light-years from Earth. The neutrino has been traveling since the universe was roughly 3 billion years old. The galaxy has an infrared luminosity of about 33 trillion times that of the Sun, magnified by gravitational lensing from a foreground galaxy. Its core is approximately 1,500 light-years across and is compact, with dense concentrations of gas and dust that fuel intense star formation. No evidence of an active supermassive black hole was found.
If confirmed, Shadow Blaster would be the first individual dusty star-forming galaxy directly linked to a high-energy neutrino event.
Detection and Observations
The neutrino alert triggered follow-up observations across the electromagnetic spectrum. No counterpart was detected by gamma-ray, X-ray, or optical telescopes, and no associated supernova, gamma-ray burst, or tidal disruption event was found. An international team led by Yuji Urata used the JCMT and SMA to identify Shadow Blaster as a candidate source. Later observations with ALMA and the Gemini North telescope (using the GMOS and GNIRS instruments) confirmed its properties and measured the foreground gravitational lens.
Significance and Implications
The absence of an active black hole suggests that star formation regions alone can accelerate particles to high energies. Researchers estimate that similar star-forming galaxies may contribute up to approximately 20% of the diffuse neutrino background measured by IceCube. Many such galaxies, however, may be too faint to study without the benefit of gravitational lensing.
"This is the first time a compact, dusty star-forming galaxy has been directly linked to a high-energy neutrino event."
Vaporized Metals Detected in Cloud Obscuring Distant Star
A massive cloud containing vaporized metals was detected causing the star J0705+0612 to dim significantly for nearly nine months. The findings, based on observations made using the Gemini South telescope, provide insight into processes shaping planetary systems after their formation.
Observation Timeline
In September 2024, the star J0705+0612, located 3,000 light-years away and similar to the Sun, became approximately 40 times dimmer. This dimming persisted until May 2025.
Data Analysis
Researchers, led by Nadia Zakamska of Johns Hopkins University, conducted observations using the Gemini South telescope, the Apache Point Observatory 3.5-meter telescope, and the 6.5-meter Magellan Telescopes. Combining these with archival data, the team determined the star was temporarily obscured by a vast, slow-moving cloud of gas and dust. The cloud is estimated to be approximately two billion kilometers from its host star and about 200 million kilometers in diameter.
The data indicate the cloud is gravitationally bound to a secondary object that orbits the star in its outer planetary system. The nature of this object is not currently known, but it must be massive enough to maintain the cloud's cohesion. Estimates place its mass at at least several times that of Jupiter. Potential classifications for the object range from a planet to a brown dwarf or a low-mass star.
Compositional Analysis
The Gemini High-resolution Optical SpecTrograph (GHOST) instrument on Gemini South was used in March 2025. GHOST's observations dispersed the star's light into a spectrum, revealing the chemical elements in the intervening material. The data indicated the presence of multiple metals, or elements heavier than helium. The precision of the spectra allowed for direct measurement of the gas's three-dimensional motion. This is reported as the first instance astronomers have measured the internal gas motions of a disk orbiting a secondary object, detecting dynamic winds composed of gaseous metals, including iron and calcium.
System Characteristics
J0705+0612, despite exhibiting an infrared excess typically associated with young stars, is estimated to be over two billion years old. This suggests the disk is not residual material from the system's initial planet formation. Zakamska has proposed the cloud formed from a collision between two planets in the outer reaches of the star's planetary system.
"This is the first time astronomers have measured the internal gas motions of a disk orbiting a secondary object."
Exoplanet WASP-189b's Atmosphere Found to Mirror Host Star's Composition
Astronomers have reported that the exoplanet WASP-189b shares the same chemical composition as its host star. This finding provides direct observational evidence for a foundational concept in planet formation theory.
Observation and Measurement
Using the Gemini South telescope and its Immersion GRating INfrared Spectrograph (IGRINS), a team led by Jorge Antonio Sanchez achieved a simultaneous measurement of gaseous magnesium and silicon in the planet's atmosphere. This is the first such simultaneous measurement for a planet.
Planet Characteristics
WASP-189b is an ultra-hot Jupiter located approximately 320 light-years away in the Libra constellation. Ultra-hot Jupiters are characterized by temperatures high enough to vaporize rock-forming elements like magnesium and silicon, making them suitable targets for spectroscopic analysis.
Findings and Implications
The observed magnesium-to-silicon ratio in WASP-189b's atmosphere matches that of its host star. This validates the assumption that the ratio of rock-forming elements in a protoplanetary disk, and subsequently the planets formed within it, mirrors the composition of the host star. This assumption, previously based on Solar System measurements, is used for modeling rocky exoplanets.
The confirmed chemical link between stars and their planets allows scientists to infer the composition of exoplanets from their stars. This can help understand conditions necessary for habitability, such as the presence of elements vital for magnetic fields, plate tectonics, and life-sustaining chemical cycles on Earth.
"The confirmed chemical link between stars and their planets allows scientists to infer the composition of exoplanets from their stars."