Related papers: Comet Machholz (C/2004 Q2): morphological structur…
C/2017 K2 (PANSTARRS) is an Oort cloud comet previously observed to be active at heliocentric distances r>20 au on what is likely its first passage through the inner solar system. We observed the comet on 2021 March 19-20 at r=6.82 au…
We present high angular resolution Submillimeter Array observations ofthe outbursting Jupiter family comet 17P/Holmes on 2007 October 26-29, achieving a spatial resolution of 2.5", or ~3000 km at the comet distance. The observations…
An analysis is presented for the photometric data on comet C/2013 A1 (Siding Spring) from observations at a large heliocentric distance (near 4.1 AU). Comet C/2013 A1 (Siding Spring) displays intense activity despite the relatively large…
Comet 103P/Hartley 2 made a close approach to the Earth in October 2010. It was the target of an extensive observing campaign and was visited by the Deep Impact spacecraft (mission EPOXI). We present observations of HCN and CH3OH emission…
Comet C/2017 K2 (PANSTARRS) was discovered by the Pan-STARRS1 (PS1) Survey on 2017 May 21 at a distance 16.09 au from the Sun, the second most distant discovery of an active comet. Pre-discovery images in the PS1 archive back to 2014 and…
Comet 17P/Holmes underwent the largest cometary outburst in recorded history on UT 2007 Oct. 23, releasing massive quantities of dust and gas. We used the Canada-France-Hawaii telescope to obtain wide-field images of 17P/Holmes on 15 dates…
We report observations of color in the inner coma of Comet C/2013 UQ4 (Catalina) with the broadband B and R filters. We find significant temporal variations of the color slope, ranging from -12.67 $\pm$ 8.16 \% per 0.1~$\mu$m up to $35.09…
We present a photometric and dynamical study of comet C/2010 U3 (Boattini), which was seen active in prediscovery data as early as 2005 November at a new inbound record heliocentric distance $r_{\rm H} = 25.8$ au. Two outburst events around…
We present new lightcurve measurements of Comet 10P/Tempel 2 carried out with Lowell Observatory's Discovery Channel Telescope in early 2013 when the comet was at aphelion. These data represent some of the first science obtained with this…
Photometric and spectroscopic observations of five nearly parabolic comets with eccentricity larger than 0.99 at heliocentric distances greater than 4 AU were performed. No molecular emission was observed for any studied comet and the…
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 an analysis of thermal emission from comet 162P/Siding Spring (P/2004 TU12) measured during its discovery apparition in 2004 December. The comet showed no dust coma at this time, so we have sampled emission from the comet's…
Samarasinha & Mueller (2013) related changes of cometary rotation to other physical parameters for four Jupiter family comets defining a parameter $X$, which is approximately constant within a factor of two irrespective of the active…
Comets, during their journeys into the inner solar system, deliver volatile gases, organics, and particulates into their comae that provide crucial information for assessing the physico-chemical conditions in the outer disk from which they…
We studied C/2025 D1 (Groeller), a long-period comet with an unprecedented perihelion distance of 14.1 au, using archival observations. The data reveals that it had been active at inbound heliocentric distances $r_{\rm H} \gtrsim 20$ au.…
We present recent observations of main-belt comet P/2010 R2 (La Sagra) obtained using the Gemini North telescope on five nights in late 2011 and early 2013 during portions of the object's orbit when dust emission was expected to be minimal…
We present follow-up observations of comet 17/P Holmes after its extreme outburst in brightness, which occurred end of October 2007. We obtained 58 V-band images of the comet between October 2007 and February 2008, using the…
A photometric method is described for accurately quantifying the brightness of short-period comets far from perihelion. The method utilizes the Sloan Digital Sky Survey Catalog (Data Release 7) as a homogeneous source of reference star…
The rotations of cometary nuclei are known to change in response to outgassing torques. The nucleus of comet 41P/Tuttle-Giacobini-Kresak exhibited particularly dramatic rotational changes when near perihelion in 2017 April. Here, we use…
In this study, the dust loss of comet C/2023 A3 (Tsuchinshan-ATLAS) is investigated through the analysis of archival images. By measuring the surface brightness profile of the coma, we determined that the comet maintained nearly in a steady…