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We analyse the population of near-Earth Long-Period Comets (LPCs) (perihelion distances q < 1.3 AU and orbital periods P > 10^3 yr). We have considered the sample of LPCs discovered during the period 1900-2009 and their estimated absolute…

We present new analyses of the photometric lightcurve of Comet 1P/Halley during its 1985/86 apparition. As part of a world-wide campaign coordinated by the International Halley Watch (IHW), narrowband photometry was obtained with telescopes…

The spectra and images obtained through broadband BVR filters for Jupiter famaly comet P/2011 P1 were analyzed. We observed the comet on November 24, 2011, when its heliocentric distance was 5.43 AU. Two dimensional long slit spectra and…

Interstellar comet 3I/ATLAS has been approaching its 2025 October 29 perihelion while opposite the Sun from Earth, hindering ground-based optical observations over the preceding month. However, this geometry placed the comet within the…

Comet P/2019 LD2 has orbital elements currently resembling those of a Jupiter Trojan, and therefore superficially appears to represent a unique opportunity to study the volatile content and active behavior of a member of this population for…

The quasi-Hilda comets (QHCs), being in unstable 3:2 Jovian mean motion resonance, are considered a major cause of temporary satellite capture (TSC) by Jupiter. Though the QHCs may be escaped Hilda asteroids, their origin and nature have…

We report results of intensive time-resolved imaging photometry and synoptic deep imaging of the comet C/2012 S1 (ISON) performed in February 2013. The data were obtained at the Wise Observatory in Israel (WO), at the Himalayan Chandra…

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 the discovery of a minor planet (2006 SQ372) on an orbit with a perihelion of 24 AU and a semimajor axis of 796 AU. Dynamical simulations show that this is a transient orbit and is unstable on a timescale of 200 Myrs. Falling near…

We observed comet 322P/SOHO 1 (P/1999 R1) from the ground and with the Spitzer Space Telescope when it was between 2.2 and 1.2 AU from the Sun. These are the first observations of any SOHO-discovered periodic comet by a non-solar…

Photometric observations of V597 Pup made in 2008, 9.1 mag below maximum, 4 months after eruption, showed no certain orbital modulation but exhibited a quintuplet of oscillations centred on a period 261.9 s and uniform splitting at a…

(1) We find that comet 107P/WH was active in 1949, 1979, 1992, 2005, and 2009. (2) Its age can be measured. We find T-AGE=4700 comet years, WB-AGE=7800 cy. (3) This is a methuselah comet very near to its dormancy phase, being temporarily…

I investigate whether comet 1P/Halley participates in the 1,151-year planetary quasi-period T* identified in a companion paper (Baiget Orts 2026a, arXiv:2604.03049). Using historical perihelion records spanning 2,225 years (30 apparitions,…

We report the discovery of activity emanating from (18916) 2000 OG44 (alternately designated 1977 SD), a minor planet previously reported to be both an extinct comet or an asteroid on a cometary orbit. We observed 2000 OG44 with a thin tail…

We present a summary of the campaign of remote observations that supported the European Space Agency's Rosetta mission. Telescopes across the globe (and in space) followed comet 67P/Churyumov-Gerasimenko from before Rosetta's arrival until…

We present CCD VR_C observations of 6 distant comets located at heliocentric distances of 3.4--7.2 AU. Time-series data were obtained on three nights in July, 2000 covering 16 hours. Each comet was observed after the perihelion, when a…

We make the following predictions: (1) Comet 67P/Churyumov-Gerasimenko. The Secular Light Curve (SLC) of this comet exhibits a photometric anomaly in magnitude that is present in 1982, 1996, 2002 and 2009. Thus it must be real. We interpret…

The orbital motion of the transiting hot Jupiter TrES-5 b was reported to be perturbed by a planetary companion on a nearby orbit. Such compact systems do not frequently occur in nature, and learning their orbital architecture could shed…

The unique inner-belt asteroid 311P/PANSTARRS (formerly P/2013 P5) is notable for its sporadic, comet-like ejection of dust in nine distinct epochs spread over $\sim$250 days in 2013. This curious behavior has been interpreted as the…

During its two years mission around comet 67P/Churyumov-Gerasimenko, ESA's Rosetta spacecraft had the unique opportunity to follow closely a comet in the most active part of its orbit. Many studies have presented the typical features…