We present high-resolution imaging observations of interstellar comet 2I/Borisov (formerly
C/2019 Q4) obtained using the Hubble Space Telescope. Scattering from the comet is …

We present a study of interstellar comet 2I/2019 Q4 (Borisov) using both preperihelion and
postperihelion observations spanning late September 2019 through late January 2020. The …

We present a high-resolution observation of the distant comet C/2014 UN 271 (Bernardinelli–
Bernstein) using the Hubble Space Telescope on 2022 January 8. The signal of the nucleus …

Recent observations show activity in long-period comet C/2017 K2 at heliocentric distances
beyond the orbit of Uranus. With this as motivation, we constructed a simple model that takes …

Context. We analyze the results of our comprehensive observations of the high-perihelion
comet C/2014 B1 (Schwartz) with stable disk-shaped coma and jets in order to study its …

We processed images taken with the Hubble Space Telescope (HST) to investigate any
morphological features in the inner coma suggestive of a peculiar activity on the nucleus of …

Agglomerated debris particles are realistic model cosmic dust particles that reproduce their
highly irregular and fluffy morphology. We compute the absolute magnitude of these model …

The analysis of photometrical observations of comet 29P/Schwassmann–Wachmann 1 is
presented. The broadband observations were carried out for 15 nights from 2012 to 2019 at …

A morphological and photometric analysis of the naked-eye long-period comet C/2022 E3
(ZTF) before perihelion is presented in this study. The observation images taken by the …

Hyperactive comet activity typically becomes evident beyond the frost line (∼ 3–4 au) where
it becomes too cold for water-ice to sublimate. If carbon monoxide (CO) and carbon dioxide …