Related papers: The Interstellar Interlopers
2I/Borisov is the first-ever observed interstellar comet (and the second detected interstellar object). It was discovered on 30 August 2019 and has a heliocentric orbital eccentricity of ~ 3.35, corresponding to a hyperbolic orbit that is…
Outer satellites of the planets have distant, eccentric orbits that can be highly inclined or even retrograde relative to the equatorial planes of their planets. These irregular orbits cannot have formed by circumplanetary accretion and are…
In studies of the oldest solar system bodies - comets and asteroids - it is their fragments - meteoroids - that provide the most accessible planetary material for detailed laboratory analysis in the form of dust particles or meteorites.…
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…
There exists a number of astronomical spectral phenomena that have remained unidentified after decades of extensive observations. The diffuse interstellar bands, the 220 nm feature, unidentified infrared emission bands, extended red…
We present a three-year series of observations at 24 microns with the Spitzer Space Telescope of the interstellar material in a 200 x 200 arcmin square area centered on Cassiopeia A. Interstellar dust heated by the outward light pulse from…
We study the destruction and modification of icy interstellar objects by cosmic rays and gas collisions. Using the cosmic-ray flux measured in the local interstellar medium as well as inferred from gamma-ray observations at the different…
Different pieces of observational evidence suggest the existence of disks around isolated neutron stars. Such disks could be formed from supernova fallback when neutron stars are born in core-collapse supernova explosions. Efforts have been…
Most observed extrasolar planets have masses similar to, but orbits very different from, the gas giants of our solar system. Many are much closer to their parent stars than would have been expected and their orbits are often rather…
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…
We explore what may be learned by close encounters between extrasolar minor bodies like `Oumuamua and the Sun. These encounters may yield strong constraints on the bulk composition and possible origin of `Oumuamua-like objects. We find that…
Stellar occultations have been used to search for Kuiper Belt and Oort Cloud objects. We propose a search for interstellar objects based on the characteristic durations ($\sim 0.1 \mathrm{s}$) of their stellar occultation signals and high…
We propose that interstellar extreme scattering events, usually observed as pulsar scintillations, may be caused by a coherent agent rather than the usually assumed turbulence of $\rm H_2$ clouds. We find that the penetration of a flux of…
Observations of the first interstellar minor object 1I/2017 'Oumuamua did not reveal direct signs of outgassing that would have been natural if it had volatile-rich composition. However, a recent measurement by Micheli et al (2018) of a…
We describe the structural and kinematic properties of the first compact stellar systems discovered by the AIMSS project. These spectroscopically confirmed objects have sizes ($\sim$6 $<$ R$_{\rm e}$ [pc] $<$ 500) and masses…
3I/ATLAS, the third discovered interstellar object, has a heliocentric speed of 58 km/s and exhibits cometary activity. To constrain the origin of 3I/ATLAS and its past dynamical evolution, we propagate the orbits of 3I/ATLAS and nearby…
The unusual morphology of the Andromeda Spiral (Messier 31, the closest spiral galaxy to the Milky Way) has long been an enigma. Although regarded for decades as showing little evidence of a violent history, M~31 has a well-known outer ring…
The recent discovery by Pan-STARRS1 of 1I/2017 U1 (`Oumuamua), on an unbound and hyperbolic orbit, offers a rare opportunity to explore the planetary formation processes of other stars, and the effect of the interstellar environment on a…
Although the existence of a faint background of starlight in the core of the Coma cluster has been well established (1,2), its origin is uncertain. This vast sea of stars could have formed outside the galaxies, using gas left over from the…
We explore the origin of a population of distant companions (~1000 - 5000 AU) to Class I protostellar sources recently found by Connelley and co-workers, who noted that the companion fraction diminished as the sources evolved. Here we…