Comet C/2018 V1 (Machholz-Fujikawa-Iwamoto): dislodged from the Oort Cloud or coming from interstellar space?

Abstract: The chance discovery of the first interstellar minor body, 1I/2017 U1 (`Oumuamua), indicates that we may have been visited by such objects in the past and that these events may repeat in the future. Unfortunately, minor bodies following nearly parabolic or hyperbolic paths tend to receive little attention: over 3/4 of those known have data-arcs shorter than 30 d and, consistently, rather uncertain orbit determinations. This fact suggests that we may have observed interstellar interlopers in the past, but failed to recognize them as such due to insufficient data. Early identification of promising candidates by using N-body simulations may help in improving this situation, triggering follow-up observations before they leave the Solar system. Here, we use this technique to investigate the pre- and post-perihelion dynamical evolution of the slightly hyperbolic comet C/2018 V1 (Machholz-Fujikawa-Iwamoto) to understand its origin and relevance within the context of known parabolic and hyperbolic minor bodies. Based on the available data, our calculations suggest that although C/2018 V1 may be a former member of the Oort Cloud, an origin beyond the Solar system cannot be excluded. If extrasolar, it might have entered the Solar system from interstellar space at low relative velocity with respect to the Sun. The practical feasibility of this alternative scenario has been assessed within the kinematic context of the stellar neighbourhood of the Sun, using data from Gaia second data release, and two robust solar sibling candidates have been identified. Our results suggest that comets coming from interstellar space at low heliocentric velocities may not be rare.

• The paper utilizes N-body simulations and observational data to analyze the trajectory of Comet C/2018 V1 and investigate its possible origins.
• Statistical analysis suggests approximately a 73% likelihood that Comet C/2018 V1 has an extrasolar origin, consistent with kinematic analogues among neighboring stars.
• The findings imply a non-negligible frequency of low-velocity interstellar objects visiting the Solar system, potentially influencing future missions like ESA's Comet Interceptor.

An Analytical Overview of the Origins of Comet C/2018 V1 (Machholz-Fujikawa-Iwamoto)

The provisional identification of comet C/2018 V1 (Machholz-Fujikawa-Iwamoto) as either a dislodged member of the Oort Cloud or an interstellar interloper is a point of significant scholarly interest. The paper by de la Fuente Marcos and de la Fuente Marcos leverages $N$-body simulations to explore the dynamical evolution of this slightly hyperbolic comet, providing insights into its possible origins and character.

The authors utilize observational data, astronomical databases, and mathematical models to analyze the trajectory and velocity profile of C/2018 V1. They posit that early identification, supported by robust simulations, can improve our ability to discern interstellar objects from those native to our Solar system. Such differentiation is predicated on observing nearly hyperbolic or parabolic paths, where historical datasets are often limited or with insufficient data-arc length for precise orbital determination.

Methodology and Data

The authors employ numerical simulations and JPL's Small-Body Database (SBDB) to examine the trajectory of C/2018 V1, with a particular focus on its pre- and post-perihelion evolution. They assess the possibility of both an Oort Cloud detachment and an interstellar origin through heliocentric and barycentric orbital analyses. The Gaia mission's second data release further enhances this investigation by providing an astrometric and photometric context within which C/2018 V1's path can be compared against neighboring stars' kinematic properties.

Findings and Outcome

Based on their simulations, the authors suggest that C/2018 V1 may not be linked to any known cometary groups. Notably, its path is distinctly separate from well-documented sungrazer clusters, such as those belonging to the Kreutz family. Statistical analyses reveal that there is approximately a 73% likelihood that C/2018 V1 had an extrasolar origin, having entered the Solar system at a relatively low heliocentric velocity. This assertion is bolstered by identifying multiple kinematic analogues to C/2018 V1 among neighboring stars, indicating that its velocity profile is consistent with known solar siblings or nearby stellar bodies.

Implications

The paper’s implications suggest a non-negligible frequency of interstellar bodies visiting the Solar system at low velocities. Such findings may influence the design and focus of future observational campaigns and missions, including ESA's Comet Interceptor project, which aims to directly explore interstellar objects. The confirmation of interstellar origins for comets like C/2018 V1 could revolutionize our understanding of Solar system dynamics and the distribution of planetary materials across star systems.

Future Directions

Looking forward, further investigation with more refined observational capabilities and atmospheric spectroscopy could verify C/2018 V1’s origins. In particular, an isotopic analysis could establish whether its composition is typical or anomalous relative to Solar system comets. Advanced simulation techniques and extensive data from ongoing and future surveys will be crucial in categorizing such interstellar visits, potentially revealing more about the nature of object exchange between our Solar system and nearby stellar environments. The pursuit of understanding these dynamics not only offers a glimpse into our own celestial neighborhood but also into the broader mechanisms of planetary and stellar formation.