Search Publications
The extent of formation of organic molecules in the comae of comets showing relatively high activity
Acharyya, Kinsuk; Ahmed, Sana
Comets are a rich reservoir of complex organic molecules. Ground and space-based observatories have recently greatly enhanced the cometary molecular inventory. Although these molecules' origin is believed to be the cometary nucleus, they can be partially synthesized in the coma. We studied organic molecules' nucleus versus coma origins for various…
Surface activity of H2 2
Tenishev, Valeriy; Fougere, Nicolas; Combi, Michael +3 more
On November 4, 2010, the EPOXI extended the mission of the Deep Impact spacecraft, flew by comet 103P/Hartley 2, and made a series of spectral images in both the infrared and the visible. The High-Resolution Instrument Infrared Spectrometer (HRI-IR) observed the comet and its surrounding coma, enabling maps in the light of the infrared emissions o…
Measurement of D/H and 13C/12C ratios in methane ice on Eris and Makemake: Evidence for internal activity
Lunine, J. I.; Emery, J. P.; Hammel, H. B. +13 more
James Webb Space Telescope's NIRSpec infrared imaging spectrometer observed the outer solar system dwarf planets Eris and Makemake in reflected sunlight at wavelengths spanning 1 through 5 µm. Both objects have high albedo surfaces that are rich in methane ice, with a texture that permits long optical path lengths through the ice for solar p…
Sublimation and infrared spectral properties of ammonium cyanide
Gerakines, Perry A.; Yarnall, Yukiko Y.; Hudson, Reggie L.
The ammonium ion (NH4+) has been suggested to be present in interstellar ices and has been observed on the surfaces of planetary bodies using infrared (IR) spectroscopy as the primary means of identification. Evidence for several ammonium salts has also been found in the dust and surface ices of comet 67P/Churyumov-Gerasimenk…
First holistic modelling of meteoroid ablation and fragmentation: A case study of the Orionids recorded by the Canadian Automated Meteor Observatory
Vida, Denis; Brown, Peter G.; Campbell-Brown, Margaret +1 more
18 mm-sized Orionid meteoroids were captured in 2019 and 2020 by the Canadian Automated Observatory's mirror tracking system. Meteor position measurements were made to an accuracy of ∼1m and the meteors were tracked to a limiting magnitude of about + 7 . 5 at the faintest point. The trajectory estimation shows the intrinsic physical dispersion of …
Comets, sliding of surface dust on illuminated surfaces
Kossacki, Konrad J.; Wesołowski, Marcin; Mikołajków, Tomasz +1 more
In our paper we presented the results of our laboratory experiments dealing with the formation and sliding of the desiccated nonvolatile granular material down the samples of potential cometary analogs. The studied samples were composed of porous aggregates containing water ice, quartz sand and charcoal. Their surfaces were initially free of desic…
New gravity field of comet 67P/C-G based on Rosetta's Doppler and optical data
Marty, Jean-Charles; Jorda, Laurent; Le Maistre, Sebastien +3 more
The gravity field of a celestial body gives valuable insights into its fundamental properties such as its density and internal structure. The Doppler data collected by the Radio-Science Investigation (RSI) experiment of the Rosetta mission were previously used to determine the gravity field of comet 67P/Churyumov–Gerasimenko up to degree 2 (Pätzol…
Modeling the plasma composition of 67P/C-G at different heliocentric distances
Ahmed, Sana; Soni, Vikas
The Rosetta spacecraft accompanied the comet 67P/C-G for nearly 2 years, collecting valuable data on the neutral and ion composition of the coma. The Rosetta Plasma Consortium (RPC) provided continuous measurements of the in situ plasma density while ROSINA-COPS monitored the neutral composition. In this work, we aim to estimate the composition of…
Common origin of trapped volatiles in oxidized icy moons and comets
Johnson, Robert E.; Oza, Apurva V.
Following spacecraft encounters with comets 67P/C-G and 1P/Halley, it was surprising that O2, expected to be a very minor species in their comas, was observed to outgas at a few percent abundance during their ice sublimation phases. This challenged the direct connection suggested between comets and material in the interstellar medium (I…
A race against the clock: Constraining the timing of cometary bombardment relative to Earth's growth
Nesvorný, David; Avice, Guillaume; Raymond, Sean N. +3 more
Comets are considered a potential source of inner solar system volatiles, but the timing of this delivery relative to that of Earth's accretion is still poorly understood. Measurements of xenon isotopes in comet 67P/Churyumov-Gerasimenko revealed that comets partly contributed to the Earth's atmosphere. However, there is no conclusive evidence of …