Related papers: Coma composition and profiles of comet 12P/Pons-Br…

We present optical and near-infrared (NIR) observations of the outbursting, Halley-type comet 12P/Pons-Brooks. Three NIR spectra were obtained during two outbursts in October and November 2023, with the 3-meter Infrared Telescope Facility…

{The multiple outburst events of comet 12P/Pons-Brooks during its 2024 apparition offer a unique window into highly-active volatile releasing processes not observable during quiescent periods. We performed radio observations of comet…

Comet 12P/Pons-Brooks is a periodic comet with an orbital period of approximately 71 years. Because of the period duration, aphelion of 35.3 au, and highly inclined orbit (74.2 deg), it is classified as a Halley-type comet. In this work, we…

During its most recent return, comet 12P/Pons-Brooks experienced 14 well-documented outbursts, observed between June 13, 2023, and April 2024, at heliocentric distances ranging from $4.26\,$au to $0.85\,$au. After perihelion, two additional…

Although the optical cometary database is extensive, the radio database is limited. The 18-cm OH maser observations of comets allow us to determine (i) the production rate of OH ($Q_{\rm{OH}}$) and (ii) the water expansion velocity, for…

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…

We present optical observations of Halley type comet 12P/Pons-Brooks on its approach to perihelion. The comet was active even in the first observations at about 8 au. Starting at 4 au, 12P exhibited an extraordinary series of outbursts, in…

We present multi-epoch optical spectroscopy of the interstellar comet 3I/ATLAS obtained between December 2025 and January 2026 (heliocentric distances 1.8-3.3 au), yielding post-perihelion production rates and mixing ratios for CN, C$_3$,…

We report on our extensive photometry and imaging of Comet 46P/Wirtanen during its 2018/19 apparition and use these data to constrain modeling of Wirtanen's activity. Narrowband photometry was obtained on nine epochs from 2018 October…

Water ice is a fundamental building material of comets and other bodies in the outer solar system. Yet, the properties of cometary water ice are challenging to study, due to its volatility and the typical distances at which comets are…

We present the results of imaging photometric and long-slit spectroscopic observations of comet 2P/Encke performed at the heliocentric distance 0.56 au, geocentric distance 0.65 au, and phase angle 109.2 deg on November 4, 2013 and at 1.05…

Comet 12P/Pons-Brooks is an intermediate-period comet (orbital period around 71 years) comparable to 1P/Halley. The comet was seen first in 1812, and then again in 1883 and 1954. The comet was recovered in 2020 an will pass its perihelion…

We report results from broadband visible images of comet C/2012 S1 (ISON) obtained with the Hubble Space Telescope Wide Field Camera 3 on 2013 April 10. C/ISON's coma brightness follows a 1/{\rho} (where {\rho} is the projected distance…

We obtained extensive narrowband photoelectric photometry of Comet 21P/Giacobini-Zinner with observations spanning 33 years. The original data from 1985 (Schleicher et al. 1987) were re-reduced and are presented along with data from three…

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…

Jupiter Family Comets (JFCs), having orbital period less than 20 years, provide us with an opportunity to observe their activity and analyse the homogeneity in their coma composition over multiple apparitions. Comet 46P/Wirtanen with its…

Based on long-slit infrared spectroscopic observations, it has been suggested that half of the carbon monoxide present in the atmosphere of comet C/1995 O1 (Hale-Bopp) close to perihelion was released by a distributed source in the coma,…

Comet C/2017 K2 (Pan-STARRS) provided a rare opportunity to investigate the evolution of coma composition and outgassing patterns over a transitional heliocentric distance (Rh) range where activity drivers in comets are thought to change…

Observations of the CO J(1-0) 115 GHz and J(2-1) 230 GHz lines in comet C/1995 O1 (Hale-Bopp) were performed with the IRAM Plateau de Bure interferometer on 11 March, 1997. The observations were conducted in both single-dish (ON-OFF) and…

The coma of comet C/2016 R2 (PanSTARRS) is one of the most chemically peculiar ever observed, in particular due to its extremely high CO/H2O and N2+/H2O ratios}, and unusual trace volatile abundances. However, the complex shape of its CO…