Related papers: Volatile-rich comets ejected early on during Solar…
Observations of comet C/2016 R2 (PanSTARRS) have revealed exceptionally bright emission bands of N$_2^+$, the strongest ever observed in a comet spectrum. Alternatively, it appears to be poor in CN compared to other comets, and remarkably…
We report on imaging and spectroscopic observations of comet C/2016~R2 (Pan-STARRS) obtained with the 0.8\,m and 2.7\,m telescopes of McDonald Observatory in November and December 2017 respectively. The comet was at a heliocentric distance…
Since 1950 when Oort published his paper on the structure of the cloud of comets it is believed that stars passing near this hypothetical cometary reservoir play an important role in the dynamical evolution of long period comets and…
In June 2021 the discovery of an unusual comet C/2014 UN271 Bernardinelli-Bernstein has been announced. Its cometary activity beyond Uranus orbit also has refreshed interest in similar objects, including C/2017K2 PanSTARRS. Another…
Context. Natural interstellar objects do not form isolated in deep space, but escape their natal planetary systems. Early removal from their home star systems via close flybys with still-forming planets could be the dominant ejection…
Distant long-period comet C/2017 K2 has been outside the planetary region of the solar system for 3 Myr, negating the possibility that heat retained from the previous perihelion could be responsible for its activity. This inbound comet is…
Based on the occurrence rates implied by the discoveries of 1I/`Oumuamua and 2I/Borisov, the forthcoming Rubin Observatory Legacy Survey of Space and Time (LSST) should detect $\ge1$ interstellar objects every year (Hoover et al. 2021). We…
Comets spend most of their lives at large distances from any star, during which time their interior compositions remain relatively unaltered. Cometary observations can therefore provide direct insight into the chemistry that occurred during…
Interstellar comets offer direct samples of volatiles from distant protoplanetary disks. 2I/Borisov is the first notably active interstellar comet discovered in our solar system[1]. Comets are condensed samples of the gas, ice, and dust…
CO and CO$_2$ are the two dominant carbon-bearing molecules in comae and have major roles in driving activity. Their relative abundances also provide strong observational constraints to models of solar system formation and evolution but…
Hypervolatile species such as carbon monoxide (CO) and molecular nitrogen (N2) have been detected in comets, and could be used to constrain comet formation temperature conditions if their presence is due to freeze-out and/or entrapment.…
We report a new imaging spectroscopic observation of Oort-cloud comet C/2017 K2 (hereafter K2) on its way to perihelion at 2.53 au, around a heliocentric distance where H2O ice begins to play a key role in comet activation. Normalized…
We present new, ice species-specific New Horizons/Alice upper gas coma production limits from the 01 Jan 2019 MU69/Arrokoth flyby of Gladstone et al. (2021) and use them to make predictions about the rarity of majority hypervolatile (CO,…
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, and 23 at a heliocentric distance…
We present observations showing in-bound long-period comet C/2017 K2 (PANSTARRS) to be active at record heliocentric distance. Nucleus temperatures are too low (60 K to 70 K) either for water ice to sublimate or for amorphous ice to…
Low-mass protostars are the extrasolar analogues of the natal Solar System. Sophisticated physicochemical models are used to simulate the formation of two protoplanetary discs from the initial prestellar phase, one dominated by viscous…
The presence of numerous complex organic molecules (COMs; defined as those containing six or more atoms) around protostars shows that star formation is accompanied by an increase of molecular complexity. These COMs may be part of the…
Comets provide a valuable window into the chemical and physical conditions at the time of their formation in the young solar system. We seek insights into where and when these objects formed by comparing the range of abundances observed for…
Observations of comets and asteroids show that the Solar Nebula that spawned our planetary system was rich in water and organic molecules. Bombardment brought these organics to the young Earth's surface, seeding its early chemistry. Unlike…
Context: CO is an abundant species in comets, creating CO$^+$ ion with emission lines that can be observed in the optical spectral range. A good modeling of its fluorescence spectrum is important for a better measurement of the CO$^+$…