Comets and Asteroids Archives

Combined white light image of 3I/ATLAS, created by median stacking white light images produced by collapsing in wavelength individual data cubes. The field of view displayed is 40 arcsec x 40 arcsec . Intensities are in units of 10-20 ergs−1 cm−2. Countours are over plotted. Snapshot of a new interstellar comet: 3I/ATLAS has a red and featureless spectrum, MRAS

Astrochemistry, Astrogeology, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Comets and Asteroids, Imaging & Spectroscopy, Interstellar, Press Release

University Of Canterbury Team Led Study Of Interstellar Comet 3I/ATLAS

by Keith CowingDecember 30, 2025December 30, 2025

The comet 3I/ATLAS, discovered by an international team in July this year, is only the third interstellar object ever found in the history of astronomy. It is the first that […]

A)–(D). Spectrally integrated flux maps for HCN, CO, CH3OH, and CS in K2. Contour intervals in each map are given in multiples of the rms noise. The rms noise (σ, mJy beam−1 km s−1 ) is indicated in the upper left corner of each panel. Sizes and orientations of the synthesized beam (Table 1) are indicated in the lower left corner of each panel. The comet’s observer-centered illumination (ϕ ∼ 25◦ ), as well as the direction of the Sun and dust trail, are indicated in the lower right. The black cross indicates the position of the peak continuum flux. A spectrum extracted from a 10′′ diameter aperture centered on the nucleus is shown in the upper right. Contours are in 10σ increments for HCN and 5σ increments for CO, CH3OH, and CS. -- astro-ph.EP

Astrochemistry, Astrogeology, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Status Report

The Evolution in Coma Molecular Composition of Comet C/2017 K2 (PanSTARRS) Across the H2O Sublimation Zone: ALMA Imaging of an H2O-Dominated Coma

by Keith CowingDecember 29, 2025December 29, 2025

We report a survey of molecular emission from cometary volatiles using the Atacama Large Millimeter/Submillimeter Array (ALMA) toward comet C/2017 K2 (PanSTARRS) carried out on UT 2022 September 21, 22, […]

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, Status Report

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

We observed comet C/2025 A6 with FAST telescope equipped with the ultra-wideband receiver from 23rd October to 8th November 2025 and detected the OH 18-cm lines for the first time.

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, Status Report

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

by Keith CowingDecember 24, 2025December 24, 2025

The first bodies to form in the Solar System acquired their materials from stars, the presolar molecular cloud and the protoplanetary disk.

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, Status Report

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

by Keith CowingDecember 23, 2025December 23, 2025

In 2025 July, the third-ever interstellar object, 3I/ATLAS, was discovered on its ingress into the Solar System. Similar to the NASA Voyager missions sent in 1977, science probes by extraterrestrial […]

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, Status Report

Breakthrough Listen Observations Of Interstellar Object 3I/ATLAS

by Keith CowingDecember 22, 2025December 22, 2025

The interstellar object 3I/ATLAS was discovered on July 1, 2025. There is currently no evidence to suggest that it is anything other than a natural astrophysical object. However, given the […]

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

Astrochemistry, Astrogeology, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Interstellar, Press Release, 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

Since its discovery on 1 July 2025 by the Asteroid Terrestrial-impact Last Alert System (ATLAS), the object known as 3I/ATLAS has captured the popular imagination, being only the third known […]

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, Press Release, Stellar Cartography

Hubble Sees Asteroids Colliding at Nearby Star for First Time

by Keith CowingDecember 19, 2025December 19, 2025

Like a game of cosmic bumper cars, scientists think the early days of our solar system were a time of violent turmoil, with planetesimals, asteroids, and comets smashing together and […]