Related papers: CN Morphology Studies of Comet 103P/Hartley 2
We imaged Comet 252P/2000 G1 (LINEAR) (hereafter 252P) with the Hubble Space Telescope and both 252P and P/2016 BA$_{14}$ (PanSTARRS) (hereafter BA$_{14}$) with the Discovery Channel Telescope in March and April 2016, surrounding its close…
We report imaging polarimetry of segments B and C of the Jupiter-family Comet 73P/Schwassmann-Wachmann 3 in the I and H bandpasses at solar phase angles of approximately 35 and 85deg. The level of polarization was typical for active comets,…
High-dispersion (l/dl ~ 25,000) infrared spectra of Comet C/2004 Q2 (Machholz) were acquired on Nov. 28-29, 2004, and Jan. 19, 2005 (UT dates) with NIRSPEC at the Keck-2 telescope on Mauna Kea. We detected H2O, CH4, C2H2, C2H6, CO, H2CO,…
Comet 162P/Siding Spring is a large Jupiter-family comet with extensive archival lightcurve data. We report new r-band nucleus lightcurves for this comet, acquired in 2018, 2021 and 2022. With the addition of these lightcurves, the phase…
Rotationally induced mixing with subsequent dredge-up of nucleosynthesized material is discussed as a second parameter of the horizontal branch morphology in globular clusters. CNO abundances have been proposed as tracers of the dredge up…
{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…
Hubble Space Telescope observations of interstellar comet 2I/Borisov near perihelion show the ejection of large (>~100 um) particles at <~9 m/s speeds, with estimated mass-loss rates of ~35 kg/s. The total mass loss from comet Borisov…
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…
Comet C/2020 F3 (NEOWISE) was the brightest comet in the northern hemisphere since C/1995 O1 (Hale-Bopp), providing a unique opportunity to study its composition and spatial distribution of emissions. We conducted narrow-band photometry and…
The aim of this work is to characterize HCN and CH$_3$OH emission from recent comets. We used the Onsala 20-m telescope to search for millimetre transitions of HCN towards a sample of 11 recent and mostly bright comets in the period…
We report on low-spectral resolution observations of comet 9P/Tempel 1 from 1983, 1989, 1994 and 2005 using the 2.7m Harlan J. Smith telescope of McDonald Observatory. This comet was the target of NASA's Deep Impact mission and our…
We report a pre-perihelion survey of volatile emissions from comet D/2021 A1 (Leonard) with the Northern Extended Millimeter Array (NOEMA; UT 2021 Nov. 5, 21, and Dec. 1) and the Atacama Pathfinder Experiment (APEX; UT 2021 Dec. 9-10),…
Spectroscopic and spectropolarimetric observations of the pre-main sequence early-G star HD 141943 were obtained at four observing epochs (in 2006, 2007, 2009 and 2010). The observations were undertaken at the 3.9-m Anglo-Australian…
Aims: Time series of high-resolution spectra of the late B-type star HD 11753 exhibiting HgMn chemical peculiarity are used to study the surface distribution of different chemical elements and their temporal evolution. Methods:…
Comet-type periodic orbits of the circular restricted three-body problem (CR3BP) are periodic solutions that are generated from very large retrograde and direct circular Keplerian motions around the common center of mass of the primaries.…
Even though the orbital motions of most long-period comets are found to comply with the gravitational law, a rapidly increasing minority of these objects is found to display detectable outgassing-driven deviations. The systematic research…
The discovery of the first active interstellar object 2I/Borisov provides an unprecedented opportunity to study planetary formation processes in another planetary system. In particular, spectroscopic observations of 2I allow us to constrain…
The daily sunspot numbers of the whole disk as well as the northern and southern hemispheres from January 1, 1945 to December 31, 2010 are used to investigate the temporal variation of the rotational cycle length through the continuous…
We have analysed the photometric data obtained with the STEREO spacecraft for 558 non-magnetic chemically peculiar (CP) stars to search for rotational and pulsational variability. Applying the Lomb-Scargle and the phase dispersion…
Coronal loops generally trace magnetic lines of force in the upper solar atmosphere. Understanding the loop morphology and its temporal evolution has implications for coronal heating models that rely on plasma heating due to reconnection at…