相关论文: Magnitude and size distribution of long-period com…

We report on narrowband photometry and extensive imaging observations of comet C/Lulin (2007 N3) obtained at Lowell Observatory during 2008 and 2009. Enhanced CN images revealed a double corkscrew morphology with two near-polar jets…

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…

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,…

We present photometry on 23 Jupiter Family Comets (JFCs) observed at large heliocentric distance, primarily using the 2.5m Isaac Newton Telescope (INT). Snap-shot images were taken of 17 comets, of which 5 were not detected, 3 were active…

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 present a study of the three forbidden oxygen lines [OI] located in the optical region (i.e., 5577.339 \r{A} (the green line), 6300.304 \r{A} and 6363.776 \r{A} (the two red lines)) in order to better understand the production of these…

Currently, we have only limited means to probe the presence of planets at large orbital separations. Foreman-Mackey et al. searched for long-period transiting planets in the Kepler light curves using an automated pipeline. Here, we apply…

The distribution of solar system absolute magnitudes ($H$) for the near-Earth asteroids (NEAs) observable near opposition -- i.e. Amors, Apollos, and Atens ($A^3$) -- is derived from the set of ALL currently known NEAs. The result is based…

According to Munoz-Gutierrez et al. (2015) the orbit of comet 1P/Halley is chaotic with a surprisingly small Lyapunov time scale of order its orbital period. In this work we analyse the origin of chaos in Halley's orbit and the growth of…

We run simulations to determine the expected distribution of orbital elements of nearly isotropic comets (NICs) in the outer solar system, assuming that these comets originate in the Oort Cloud at thousands of AU and are perturbed into the…

Comet C/2006 W3 (Christensen) was observed in November 2009 at 3.3 AU from the Sun with Herschel. The PACS instrument acquired images of the dust coma in 70- and 160-micrometers filters, and spectra covering several H2O rotational lines.…

The apparent source region (or regions) of long-period comets as well as the definition of the dynamically new comet are still open questions.The aim of this investigation is to look for the apparent source of selected long period comets…

We identified a new ultra-distant comet C/2019 E3 (ATLAS) exhibiting preperihelion cometary activity at heliocentric distances $\gtrsim\!20$ au, making it the fourth member of this population after C/2010 U3 (Boattini), C/2014 UN$_{271}$…

Activity of most comets near the Sun is dominated by sublimation of frozen water, the most abundant ice in comets. Some comets, however, are active well beyond the water-ice sublimation limit of ~3 AU. Three bodies dominate the…

The solar system's Oort cloud can be perturbed by the Galactic tide and by individual passing stars. These perturbations can inject Oort cloud objects into the inner parts of the solar system, where they may be observed as the long-period…

Results are presented from the first cometary observations using the Atacama Large Millimeter/Submillimeter Array (ALMA), including measurements of the spatially-resolved distributions of HCN, HNC, H$_2$CO and dust within the comae of two…

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…

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…

Eleven years after its perihelion, comet C/1995 O1 (Hale-Bopp) is still active. Between October 20--22, 2007, we detected a diffuse coma of 180x10^3$km in diameter with a slight elongation toward N/S direction. The integrated brightness was…

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…