Related papers: A Dormant Captured Oort Cloud Comet Awakens: (1891…

The detached object Sedna is likely at the inner edge of the Oort cloud, more precisely the inner Oort cloud (IOC). Until recently it was the sole member of this population. The recent discovery of the detached object 2012 VP113 has…

Recently the ROSINA mass spectrometer suite on board the European Space Agency's Rosetta spacecraft discovered an abundant amount of molecular oxygen, O2, in the coma of Jupiter family comet 67P/Churyumov-Gerasimenko of O2/H2O =…

We performed a monitoring observation of a Jupiter-Family comet, 17P/Holmes, during its 2014 perihelion passage to investigate its secular change in activity. The comet has drawn the attention of astronomers since its historic outburst in…

The Oort cloud (OC) probably formed more than 4$\,$Gyr ago and has been moving with the Sun in the Galaxy since, exposed to external influences, most prominently to the Galactic tide and passing field stars. Theories suggest that other…

We report a new imaging spectroscopic observation of Oort-cloud comet C/2017 K2 (hereafter K2) on its way to perihelion at 2.53 au, around a heliocentric distance where H2O ice begins to play a key role in comet activation. Normalized…

To gain a greater insight into the impending evolution of the physical behavior of comet C/2012 S1, its light curve and orbital properties are compared with those for C/1962 C1 (Seki-Lines) and C/2002 O4 (Hoenig). All three are likely Oort…

Optical observations of the Oort cloud comet C/2017 K2 (PANSTARRS) show that its activity began at large heliocentric distances (up to 35 au), which cannot be explained by either the sublimation or the crystallization of water ice.…

The Oort Cloud remains one of the most poorly explored regions of the Solar System. We propose that its properties can be constrained by studying a population of dust grains produced in collisions of comets in the outer Solar System. We…

Equation of motion for a comet in the Oort cloud is numerically solved. Orbital evolution of the comet under the action of the gravity of the Sun and the Galaxy is presented for various initial conditions. Oscillations of the Sun with…

We present a fully integrated model of comet evolution that couples thermal and compositional processes with dynamical processes continuously, from formation to present-day activity. The combined code takes into account changes in orbital…

We report the discovery of CoRoT 102980178 (R.A.= 06:50:12.10, Dec.= -02:41:21.8, J2000) an Algol-type eclipsing binary system with a pulsating component (oEA). It was identified using a publicly available 55 day long monochromatic…

In some planet formation theories, protoplanets grow gravitationally within a young star's protoplanetary disk, a signature of which may be a localized disturbance in the disk's radial and/or vertical structure. Using time-series…

We present a chronology of the formation and early evolution of the Oort cloud by simulations. These simulations start with the Solar System being born with planets and asteroids in a stellar cluster orbiting the Galactic center. Upon…

At discovery time, C/2017 K2 (PANSTARRS) was the second most distant inbound active comet ever observed. It has been argued that this object is in the process of crossing the inner Solar System for the first time, but other authors have…

I call attention to extraordinary features displayed by the genetically related long-period comet pair of C/1844 Y1 (Great Comet) and C/2019 Y4 (ATLAS). The issue addressed most extensively is the fragmentation and disintegration of the…

Long-period comets observed in our solar system are believed to originate from the Oort cloud, which is estimated to extend from roughly a few thousand to $10^5$ AU from the Sun. Despite many theoretical arguments for its existence, no…

We present numerical simulations to model the production of observable long-period comets (LPCs) from the Oort Cloud, a vast reservoir of icy bodies surrounding the Sun. We show that inner Oort Cloud objects can penetrate Jupiter's orbit…

We utilize serendipitous observations from the Asteroid Terrestrial-impact Last Alert System (ATLAS) and the Zwicky Transient Facility (ZTF) in addition to targeted follow-up observations from the Las Cumbres Observatory (LCO) and Liverpool…

We report the discovery of 2010 GB$_{174}$, a likely new member of the Inner Oort Cloud (IOC). 2010 GB$_{174}$ is one of 91 Trans Neptunian Objects (TNOs) and Centaurs discovered in a 76 deg$^2$ contiguous region imaged as part of the Next…

Since very recently, we acquired knowledge on the existence of comets in extrasolar planetary systems. The formation of comets together with planets around host stars now seems evident. As stars are often born in clusters of interstellar…