Related papers: Comet C/2018 V1 (Machholz-Fujikawa-Iwamoto): dislo…
Context. Natural interstellar objects do not form isolated in deep space, but escape their natal planetary systems. Early removal from their home star systems via close flybys with still-forming planets could be the dominant ejection…
Context: Increasingly, Oort Cloud comets are being discovered at great distances from the Sun and tracked over ever wider ranges of heliocentric distances as observational equipment improves. Aims: To investigate in detail how the original…
Interstellar interlopers are bodies formed outside of the solar system but observed passing through it. The first two identified interlopers, 1I/`Oumuamua and 2I/Borisov, exhibited unexpectedly different physical properties. 1I/`Oumuamua…
The discovery of the first interstellar object passing through the Solar System, 1I/2017 U1 ('Oumuamua), provoked intense and continuing interest from the scientific community and the general public. The faintness of 'Oumuamua, together…
As an Oort Cloud object with a record small perihelion distance of 2.7 Rsun and discovered more than a year before its encounter with the Sun, comet C/2012 S1 is a subject of considerable scientific interest. Its activity along the orbit's…
1I/`Oumuamua is the first of likely many small bodies of extrasolar origin to be found in the solar system. These interstellar objects (ISOs) are hypothesized to have formed in extrasolar planetary systems prior to being ejected into…
We measured the degree of linear polarization P of comet C/2018 V1 (Machholz-Fujikawa-Iwamoto) with the broadband Johnson V filter in mid-November of 2018. Within a radius of \r{ho}=17,000 km of the inner coma, we detected an extremely low…
The phenomenon of 1I/'Oumuamua introduced the interstellar object (ISO) class of celestial body into the astronomical lexicon, those objects with heliocentric speeds clearly in excess of that required to parabolically escape the Solar…
Comet C/2014 UN$_{271}$, alternative designation 'BB' after its discoverers 'Bernardinelli/Bernstein', and commonly referred to as UN$_{271}$, is an extreme case on two fronts, firstly its solar distance on discovery ($>$ 29 au) and…
`Oumuamua (I1 2017) was the first macroscopic ($l\sim100\,{\rm m}$) body observed to traverse the inner solar system on an unbound hyperbolic orbit. Its light curve displayed strong periodic variation, and it showed no hint of a coma or…
1I/`Oumuamua is the first known interstellar small body, probably being only about 100~m in size. Against expectations based on comets, `Oumuamua does not show any activity and has a very elongated figure, and also exhibits undamped…
The low velocity of interstellar asteroid 1I/'Oumuamua with respect to our galaxy's Local Standard of Rest implies it is young. Adopting the young age hypothesis, we assess possible origin systems for this interstellar asteroid and for…
1I/'Oumuamua is the first interstellar interloper to have been detected. Because planetesimal formation and ejection of predominantly icy objects are common by-products of the star and planet formation processes, in this study we address…
A 2000-2017 set of long-period comets with high-quality orbits of perihelion distance <1 AU is used to show that the objects that perish shortly before perihelion are nearly exclusively the Oort Cloud comets, especially those with perihelia…
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…
We present a study of two newly discovered heliocentric hyperbolic objects -- 2017 U7 and 2018 C2. Both are possibly thermally evolved comets. Observations of the latter in 2018 March from Xingming Observatory revealed that it has a color…
Orbital elements of C2011 L4 (PanStarrs) Oort cloud comet, computed by MPC (Minor Planet Center, Minor Planet Electronic Circular 2012-T08), show that the closest approach to the Sun occurred on 2013 March 10th, at about 0.3 A.U., then…
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…
We suggest that the kinematics and properties of interstellar object A/2017 U1 point towards its formation in a protoplanetary disk in the ~45 Myr-old Carina or Columba young stellar associations, and subsequent ejection with a low peculiar…
1I/2017 U1 'Oumuamua is the first interstellar object recorded inside the Solar System. We try to answer the main question: where does it come from? To this aim we searched for close encounters between 'Oumuamua and all nearby stars with…