相关论文: Millimetre continuum observations of comet C/2009 …

The results of the photometric observations of comet C/2009 P1 (Garradd) performed at the 60-cm Zeiss-600 telescope of the Terskol observatory have been analyzed. During the observations, the comet was at the heliocentric and geocentric…

We used the UltraViolet-Optical Telescope on board Swift to observe the dynamically young comet C/2009 P1 (Garradd) from a heliocentric distance of 3.5 AU pre-perihelion until 4.0 AU outbound. At 3.5 AU pre-perihelion, comet Garradd had one…

We present a study of the newly-discovered main-belt comet P/2008 R1 (Garradd), an object with the dynamical characteristics of an asteroid and the physical characteristics of a comet. Photometry sets a limit to the effective radius of the…

We present the results of photometry, linear spectropolarimetry, and imaging circular polarimetry ofcomet C/2009 P1 (Garradd) performed at the 6-m telescope BTA of the Special Astrophysical Observatory(Russia) equipped by the multi-mode…

We present observations of the main-belt comet 259P/Garradd, previously known as P/2008 R1 (Garradd), obtained in 2011 and 2012 using the Gemini North Telescope on Mauna Kea in Hawaii, and the SOAR Telescope at Cerro Pachon in Chile, with…

We present the optical imaging polarimetric observations of comet C/2009 P1(Garradd) at three different phase angles e.g., 28.2$^\circ$, 28.1$^\circ$ and 21.6$^\circ$. The observations were carried out using IUCAA Faint Object Spectrograph…

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…

The recently announced Oort-cloud comet C/2014 UN271 (Bernardinelli-Bernstein) is remarkable in at least three respects: (i) it was discovered inbound as far as ~29 au from the Sun (with prediscovery images up to ~34 au); (ii) it showed…

Little is known about the physical properties of cometary nuclei. Apart from space mission targets, measuring the thermal emission of a nucleus is one of the few means to derive its size, independently of its albedo, and to constrain some…

Comet 17P/Holmes underwent a dramatic outburst in October 2007, caused by the sudden fragmentation of its nucleus and the production of a large quantity of grains scattering sunlight. We report on 90 GHz continuum observations carried out…

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 present observations of main-belt comet 259P/Garradd from four months prior to its 2017 perihelion passage to five months after perihelion using the Gemini North and South telescopes. The object was confirmed to be active during this…

The High Resolution Instrument Infrared Spectrometer (HRI-IR) onboard the Deep Impact Flyby spacecraft detected H2O, CO2, and CO in the coma of the dynamically young Oort cloud comet C/2009 P1 (Garradd) post-perihelion at a heliocentric…

The D/H ratio in cometary water is believed to be an important indicator of the conditions under which icy planetesimals formed and can provide clues to the contribution of comets to the delivery of water and other volatiles to Earth.…

We report mid-IR interferometric measurements with \sim 10 mas resolution, which resolve the warm (T = 285 +25 / -50 K) thermal emission at the center of NGC 4151. Using pairs of VLT 8.2 m telescopes with MIDI and by comparing the data to a…

Possibilities of measuring the size of nuclei of comets hidden by dust clouds are discussed. To this end, the dust cloud should be irradiated with a flow of rods accelerated in a linear mass accelerator to the velocity six kilometers per…

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…

We present analysis of high spectral resolution NIR spectra of CO and H$_2$O in comet C/2009 P1 (Garradd) taken during its 2011-2012 apparition with the CSHELL instrument on NASA's Infrared Telescope Facility (IRTF). We also present…

Spectrophotometric monitoring of distant comet C/2002 VQ94 (LINEAR) was performed with the 6-m telescope of SAO RAS and with the 2.5-m Nordic Optical Telescope between 2008 and 2013. During this period the comet was on the outbound segment…

A sequence of events, dominated by two outbursts and ending with the preperihelion disintegration of comet C/2017 S3, is examined. The onset times of the outbursts are determined with high accuracy from the light curve of the nuclear…