What and Whence 1I/`Oumuamua: A Contact Binary from the Debris of a Young Planetary System?
arXiv:1712.06721 · doi:10.1093/mnras/sty1072
Abstract
The first confirmed interstellar interloper in our Solar System, 1I/`Oumuamua, is likely to be a minor body ejected from another star, but its brief flyby and faintness made it difficult to study. Two remarkable properties are its large (up to 2.5 mag) rotational variability and its motion relative to the Sun before encounter. The former suggests an extremely elongated shape (aspect ratio ~10) and the latter an origin from the protoplanetary disk of a young star in a nearby association. Against expectations, it is also not comet-like. 1I/`Oumuamua's variability can also be explained if it is a contact binary composed of near-equilibrium ellipsoidal components and heterogeneous surfaces, i.e. brighter, dust-mantled inner-facing hemispheres and darker, dust-free outer-facing poles. Such shapes are a plausible outcome of radiation, tides and collisions in systems where planets are clearing planetesimal disks. The probability that 1I/`Oumuamua has the same motion as a young (<~100 Myr) stellar association by coincidence is <1%. If it is young, its detection vs. more numerous, older counterparts could be explained as a selection effect due to darkening of surfaces by Galactic cosmic rays and loss of dust. 1I/`Oumuamua's apparent lack of ices can be explained if ejected rocky planetesimals are characteristically smaller and thus far more numerous than their icy counterparts: the Solar System may currently host several such objects captured by the combined gravity of Jupiter and the Sun.
arXiv commentMNRAS
References in corpus (28)
- Dynamical Outcomes of Planet-Planet Scattering
- Density of asteroids
- Empirical Color Transformations Between SDSS Photometry and Other Photometric Systems
- BANYAN. II. Very Low Mass and Substellar Candidate Members to Nearby, Young Kinematic Groups With Previously Known Signs of Youth
- Milky Way Mass Models for Orbit Calculations
- Formation and Evolution of Planetary Systems (FEPS): Properties of Debris Dust around Solar-type Stars
- Steady-State Size Distributions for Collisional Populations: Analytical Solution with Size-Dependent Strength
- Young Nearby Loose Associations
- An Observational Upper Limit on the Interstellar Number Density of Asteroids and Comets
- Age velocity dispersion relations and heating histories in disc galaxies
- Will the Large Synoptic Survey Telescope detect extra-solar planetesimals entering the solar system?
- Re-examining the membership and origin of the Epsilon Cha association
- Asteroid lightcurves from the Palomar Transient Factory survey: Rotation periods and phase functions from sparse photometry
- The Decay of Debris Disks around Solar-Type Stars
- Implications of the interstellar object 1I/'Oumuamua for planetary dynamics and planetesimal formation
- The Puzzling Mutual Orbit of the Binary Trojan Asteroid (624) Hektor
- Realistic Detectability of Close Interstellar Comets
- Coagulation Calculations of Icy Planet Formation at 15--150 AU: A Correlation Between the Maximum Radius and the Slope of the Size Distribution for Transneptunian Objects
- `Oumuamua as a messenger from the Local Association
- A Correlation Between Circumstellar Disks and Rotation in the Upper Scorpius OB Association
- Effect of rotational disruption on the size-frequency distribution of the Main Belt asteroid population
- Magnitude and size distribution of long-period comets in Earth-crossing or approaching orbits
- A stellar census of the nearby, young 32 Orionis group
- Prospects for Backtracing 1I/`Oumuamua and Future Interstellar Objects
- Astronomical Oxygen Isotopic Evidence for Supernova Enrichment of the Solar System Birth Environment by Propagating Star Formation
- A revised moving cluster distance to the Pleiades open cluster
- Very Low-Mass Stars and Brown Dwarfs in Upper Scorpius using Gaia DR1: Mass Function, Disks and Kinematics
- On the oxygen isotopic composition of the Solar System
Cited by in corpus (16)
- The Natural History of 'Oumuamua
- Spitzer Observations of Interstellar Object 1I/`Oumuamua
- The Feasibility and Benefits of In Situ Exploration of `Oumuamua-like objects
- The Dynamics of Interstellar Asteroids and Comets within the Galaxy: an Assessment of Local Candidate Source Regions for 1I/`Oumuamua and 2I/Borisov
- Origin of 1I/'Oumuamua. I. An ejected protoplanetary disk object?
- 1I/2017 'Oumuamua-like Interstellar Asteroids as Possible Messengers from the Dead Stars
- Constraints on the Occurrence of 'Oumuamua-Like Objects
- Origin of 1I/'Oumuamua. II. An ejected exo-Oort cloud object?
- Destruction of molecular hydrogen ice and Implications for 1I/2017 U1 (`Oumuamua)
- Implications of Captured Interstellar Objects for Panspermia and Extraterrestrial Life
- Assessing the Formation of Solid Hydrogen Objects in Starless Molecular Cloud Cores
- Interstellar Now! Missions to and Sample Returns from Nearby Interstellar Objects
- On the pollution of white dwarfs by exo-Oort cloud comets
- Spinup and Disruption of Interstellar Asteroids by Mechanical Torques, and Implications for 1I/2017 U1 (`Oumuamua)
- Astro2020 Science White Paper: Triggered High-Priority Observations of Dynamic Solar System Phenomena
- Implications of evaporative cooling by H for 1I/`Oumuamua