Related papers: A Comet Active Beyond the Crystallization Zone

We present IRTF/SpeX and NEOWISE observations of the dynamically new comet C/2013 US$_{10}$ (Catalina), hereafter US10, from 5.8 au inbound, to near perihelion at 1.3 au, and back to 5.0 au outbound. We detect water ice in the coma of US10,…

We present the analysis of the polarimetric and spectral data obtained for the dynamically new comet C/2012\,J1 (Catalina) when it was at a distance of 3.17~AU from the Sun. The observations were made at the prime focus of the 6-m BTA…

Recent observations of the long period comet C/2016 R2 (PanSTARRS) indicate an unusually high N2/CO abundance ratio, typically larger than 0.05, and at least 2-3 times higher than the one measured in 67P/Churyumov-Gerasimenko. Another…

29P/Schwassmann-Wachmann 1 is a distant Centaur/comet, showing persistent CO-driven activity and frequent outbursts. We used the Herschel space observatory in 2010, 2011, and 2013 to observe H$_2$O and NH$_3$ and to image the dust coma.…

We observed the new Long Period Comet C/2024 E1 (Wierzchos), inbound at 7 au from the Sun, using the NIRSpec integral field unit on JWST. The spectrum shows absorption features due to water ice in the coma and evidence for CO$_2$ driven…

Centaurs are small bodies orbiting in the giant planet region which were scattered inwards from their source populations beyond Neptune. Some members of the population display comet-like activity during their transition through the solar…

Our goal was to characterize the distant gaseous and dust activity of comet C\2012 S1 (ISON), inbound, from observations of H2O, CO and the dust coma in the far-infrared and submillimeter domains. In this paper, we report observations…

Jupiter co-orbital comets have orbits that are not long-term stable. They may experience flybys with Jupiter close enough to trigger tidal disruptions like the one suffered by comet Shoemaker-Levy 9. Our aim was to study the activity and…

We report VLT spectroscopy of the interstellar comet 3I/ATLAS (C/2025~N1) from $r_{\rm h}\!\simeq\!4.4$ to $2.85$~au using X-shooter (300--550\,nm, $R\!\simeq\!3000$) and UVES (optical, $R\!\simeq\!35k-80k$). The coma is dust-dominated with…

We aim to shed light on the physical properties and kinematics of the molecular material in the nucleus of one of the closest type 2 active galaxies. To this end, we obtained high angular resolution ALMA observations of the nucleus of the…

The detection of Interstellar Objects passing through the Solar System offers the promise of constraining the physical and chemical processes involved in planetary formation in other extrasolar systems. While the effect of outgassing by…

Centaurs are minor planets thought to have originated in the outer Solar System region known as the Kuiper Belt. Active Centaurs enigmatically display comet-like features (e.g., tails, comae) even though they orbit in the gas giant region…

Most Kreutz family sungrazing comets are discovered only days before perihelion, severely limiting observational opportunities to study their physical nature and decay. Kreutz sungrazer C/2024 S1 (ATLAS) was discovered a month before…

On 2007 October 29 the outbursting comet 17P/Holmes passed within 0.79 arcsec of a background star. We recorded the event using optical, narrowband photometry and detect a 3% to 4% dip in stellar brightness bracketing the time of closest…

We present initial results from observations and numerical analyses aimed at characterizing main-belt comet P/2012 T1 (PANSTARRS). Optical monitoring observations were made between October 2012 and February 2013 using the University of…

Long-period comet C/2018 F4 (PANSTARRS) was observed to show duplicity of its inner region in 2020 September, suggestive of a splitting event. We here present analyses of our observations of the comet taken from the LOOK project and the…

We examine the development of the active asteroid 311P/PANSTARRS (formerly, 2013 P5) in the period from 2013 September to 2014 February using high resolution images from the Hubble Space Telescope. This multi-tailed object is characterized…

We present analysis of observations of CO2 and OI emission in three comets to measure the CO2 abundance and evaluate the possibility of employing observations of OI emission in comets as a proxy for CO2. We obtained NIR imaging sensitive to…

We present polarization images of Comet ISON (C/2012 S1) taken with the Hubble Space Telescope (HST) on UTC 2013 May 8 (rh = 3.81 AU, Delta = 4.34 AU), when the phase angle was alpha = 12.16 degrees. This phase angle is approximately…

The image of comet 2I/Borisov taken by the Hubble Space Telescope on October 12 shows a fan-like feature in the inner coma, which extends over a few arcseconds from the nuclear condensation, its axis pointing a little west of the north. It…