Comets and Asteroids – Page 6 – My WordPress Site

Optical image of comet C/2025 A6 obtained on 21st October 2025 (18:35–18:50, UTC+8) with the 70-cm UCASST telescope. The image combines 5-min exposures in each of the R, V, and B filters and shows a coma with an apparent diameter of ∼8–10 arcmin. The telescope is equipped with a 2048×2048 detector with a pixel size of 13.5 µm, providing a field of view of about 20.8'×20.8', at the time of the observation, 1′ corresponds to a projected scale of ∼25,700 km at the comet. -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy

From Emission To Absorption: The FAST Observation Of The OH 18-cm Lines From The Comet C2025/A6

by Keith CowingDecember 29, 2025December 29, 2025

NanoSIMS ratio and ion images (top images) of a region containing a 17O-rich presolar silicate grain (arrows). The elemental maps and spectra from SEM-EDX analysis confirm the grain is a ferromagnesian silicate. -- Nature Astronomy via PubMed

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Comets and Asteroids, Imaging & Spectroscopy, Meteorites & Asteroids, Missions & Hardware, Sample Return

The Variety And Origin Of Materials Accreted By Bennu’s Parent Asteroid

by Keith CowingDecember 24, 2025December 24, 2025

The distribution of the ∼ 74 million hits from this survey across drift rate. Note the peak of hits around 0 Hz/s (expected because most RFI transmitters are in the same reference frame as the telescope, i.e., on the ground). After the drift rate cut, the count of hits is much more even across the restricted drift rate range. Note that the sawtooth pattern seen across drift rate is a known artifact in the current development version of bliss, caused by an overestimation of SNR for high-bandwidth (≳ 10 Hz wide) hits close to integer multiples of the unit drift rate. It causes increased amounts of false positives close to these drift rates but does not cause false negatives (for more details, see Jacobson-Bell et al. 2025). -- astro-ph.EP

Astrochemistry, Astrogeology, Astronomy & Telescopes, Comets and Asteroids, Imaging & Spectroscopy, Interstellar, SETI & Technosignatures

A Search For Radio Technosignatures From Interstellar Object 3I/ATLAS With The Allen Telescope Array

by Keith CowingDecember 23, 2025December 23, 2025

Radio spectrograms from our ATA observations. The diagonal stripe at the center is visible in observations of 3I/ATLAS as well as in off-target observations - characteristics expected from local (human) sources of interference - and hence can be rejected as a candidate technosignature (image: Sheikh et al. 2025).

Astronomy & Telescopes, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Intelligence & Language, Interstellar, SETI & Technosignatures

Breakthrough Listen Observations Of Interstellar Object 3I/ATLAS

by Keith CowingDecember 22, 2025December 22, 2025

South Africa’s MeerKAT telescope. Credit: South African Radio Astronomy Observatory (SARAO).

Astrochemistry, Astrogeology, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Interstellar, SETI & Technosignatures

South African Telescope Detects Natural Radio Emission – And No Signal Of Technological Origin – From Interstellar Visitor 3I/ATLAS

by Keith CowingDecember 21, 2025December 21, 2025

This composite Hubble Space Telescope image shows the debris ring and dust clouds cs1 and cs2 around the star Fomalhaut. Fomalhaut itself is masked out to allow the fainter features to be seen. Its location is marked by the white star. Image: NASA, ESA, Paul Kalas (UC Berkeley); Image Processing: Joseph DePasquale (STScI)

Astrogeology, Astronomy & Telescopes, Comets and Asteroids, Exoplanets, -moons, -comets, Fomalhaut, Imaging & Spectroscopy, Stellar Cartography

Hubble Sees Asteroids Colliding at Nearby Star for First Time

by Keith CowingDecember 19, 2025December 19, 2025

The Southwest Research Institute-led Ultraviolet Spectrograph (UVS) aboard NASA’s Europa Clipper spacecraft made valuable observations of the interstellar comet 3I/ATLAS during a period when it was difficult to observe from Mars- and Earth-based vantage points, viewing its two tails from between their downstream directions. -- Southwest Research Institute

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Comets and Asteroids, Imaging & Spectroscopy, Interstellar

Europa Clipper Instrument Uniquely Observed Interstellar Comet 3I/ATLAS

by Keith CowingDecember 18, 2025December 19, 2025

A looming planetary impact -- Astrobiology.com

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Comets and Asteroids, Extinction events, Habitable Zones, Impact events

Planetary Impacts: Friend Or Foe?

by Keith CowingDecember 17, 2025December 17, 2025

The continuum-subtracted spectra showing emission lines from Ni (dotted red), Fe (dashed green), and CN (solid blue). -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy

University of Hawaii 88-inch Telescope Observations of the Interstellar Comet 3I/ATLAS: Spectrophotometric Blue-Sensitive Spectral Time Series Spanning Two Months from Discovery

by Keith CowingDecember 14, 2025December 14, 2025

XMM-Newton observed the comet with its European Photon Imaging Camera (EPIC)-pn camera ESA/XMM-Newton/C. Lisse, S. Cabot & the XMM ISO Team larger image

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Interstellar

XMM-Newton Sees Interstellar Comet 3I/ATLAS in X-ray Light

by Keith CowingDecember 13, 2025December 13, 2025