The natural history of ‘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 with the limited time window within which observations were possible, constrained the information available on its dynamics and physical state. Here we review our knowledge and find that in all cases, the observations are consistent with a purely natural origin for `Oumuamua. We discuss how the observed characteristics of `Oumuamua are explained by our extensive knowledge of natural minor bodies in our Solar System and our current knowledge of the evolution of planetary systems. We highlight several areas requiring further investigation.

[1]  Dimitri Veras,et al.  Post-main-sequence planetary system evolution , 2016, Royal Society Open Science.

[2]  C. Moutou,et al.  The HARPS search for southern extra-solar planets , 2004, Astronomy & Astrophysics.

[3]  Mikael Granvik,et al.  REALISTIC DETECTABILITY OF CLOSE INTERSTELLAR COMETS , 2011, 1607.08162.

[4]  J. M. Moore,et al.  Overview of initial results from the reconnaissance flyby of a Kuiper Belt planetesimal: 2014 MU69 , 2019 .

[5]  David Jewitt,et al.  Project Pan-STARRS and the Outer Solar System , 2003 .

[6]  Larry Denneau,et al.  An Observational Upper Limit on the Interstellar Number Density of Asteroids and Comets , 2017, 1702.02237.

[7]  Matthias Hahn,et al.  The Nucleus of comet 67P/Churyumov–Gerasimenko – Part I: The global view – nucleus mass, mass-loss, porosity, and implications , 2018, Monthly Notices of the Royal Astronomical Society.

[8]  Andrew A. West,et al.  THE BROWN DWARF KINEMATICS PROJECT (BDKP). IV. RADIAL VELOCITIES OF 85 LATE-M AND L DWARFS WITH MagE , 2015, 1507.00057.

[9]  Fabo Feng,et al.  ‘Oumuamua as a Messenger from the Local Association , 2017, 1711.08800.

[10]  Andrew J. Connolly,et al.  APO Time-resolved Color Photometry of Highly Elongated Interstellar Object 1I/‘Oumuamua , 2017, 1711.04927.

[11]  Qicheng Zhang,et al.  Prospects for Backtracing 1I/‘Oumuamua and Future Interstellar Objects , 2017, 1712.08059.

[12]  R. Paul Butler,et al.  A New Planet around an M Dwarf: Revealing a Correlation between Exoplanets and Stellar Mass , 2007, 0707.2409.

[13]  H. Boussier,et al.  The extraordinary composition of the blue comet C/2016 R2 (PanSTARRS) , 2018, Astronomy & Astrophysics.

[14]  Edwin L. Turner,et al.  WILL THE LARGE SYNOPTIC SURVEY TELESCOPE DETECT EXTRA-SOLAR PLANETESIMALS ENTERING THE SOLAR SYSTEM? , 2009, 0908.3948.

[15]  Luca Ricci,et al.  The Disk Substructures at High Angular Resolution Project (DSHARP). VII. The Planet–Disk Interactions Interpretation , 2018, The Astrophysical Journal.

[16]  T. Joseph W. Lazio,et al.  Search for OH 18 cm Radio Emission from 1I/2017 U1 with the Green Bank Telescope , 2018, 1803.10187.

[17]  Peter H. Schultz,et al.  COMETARY VOLATILES AND THE ORIGIN OF COMETS , 2012 .

[18]  Eric Gaidos,et al.  What and whence 1I/`Oumuamua: a contact binary from the debris of a young planetary system? , 2017, 1712.06721.

[19]  David E. Trilling,et al.  Implications for Planetary System Formation from Interstellar Object 1I/2017 U1 (‘Oumuamua) , 2017, 1711.01344.

[20]  Sean N. Raymond,et al.  PLANET–PLANET SCATTERING IN PLANETESIMAL DISKS. II. PREDICTIONS FOR OUTER EXTRASOLAR PLANETARY SYSTEMS , 2010, 1001.3409.

[21]  Marco Micheli,et al.  Detection of radiation pressure acting on 2009 BD , 2011, 1106.0564.

[22]  S. F. Green,et al.  Rotation of cometary nuclei: new light curves and an update of the ensemble properties of Jupiter-family comets , 2017, 1707.02133.

[23]  Zdenek Sekanina,et al.  Preperihelion Outbursts and Disintegration of Comet C/2017 S3 (Pan-STARRS) , 2018 .

[24]  A. Morbidelli,et al.  Origin and Evolution of Short-period Comets , 2017, 1706.07447.

[25]  Susanne Pfalzner,et al.  SHORT DISSIPATION TIMES OF PROTO-PLANETARY DISKS: AN ARTIFACT OF SELECTION EFFECTS? , 2014 .

[26]  K. J. Meech,et al.  Plausible Home Stars of the Interstellar Object ‘Oumuamua Found in Gaia DR2 , 2018, The Astronomical Journal.

[27]  J. Kawaguchi,et al.  The Rubble-Pile Asteroid Itokawa as Observed by Hayabusa , 2006, Science.

[28]  R. Rafikov,et al.  1I/2017 ’Oumuamua-like Interstellar Asteroids as Possible Messengers from Dead Stars , 2018, The Astrophysical Journal.

[29]  Aaron Do,et al.  Interstellar Interlopers: Number Density and Origin of ‘Oumuamua-like Objects , 2018, 1801.02821.

[30]  Abraham Loeb,et al.  Could Solar Radiation Pressure Explain ‘Oumuamua’s Peculiar Acceleration? , 2018, The Astrophysical Journal.

[31]  Marcello Fulchignoni,et al.  An analysis of the amplitude-phase relationship among asteroids , 1990 .

[32]  Anders Johansen,et al.  Initial mass function of planetesimals formed by the streaming instability , 2016, 1611.02285.

[33]  Y. Medvedev,et al.  Dust bombardment can explain the extremely elongated shape of 1I/’Oumuamua and the lack of interstellar objects , 2018, Monthly Notices of the Royal Astronomical Society: Letters.

[34]  Shu-ichiro Inutsuka,et al.  Collisional elongation: Possible origin of extremely elongated shape of 1I/‘Oumuamua , 2019, Icarus.

[35]  G. Gilmore,et al.  The distribution of low-mass stars in the Galactic disc , 1993 .

[36]  J. S. Dohnanyi Collisional model of asteroids and their debris , 1969 .

[37]  David Jewitt,et al.  Densities of Solar System Objects from Their Rotational Light Curves , 2007 .

[38]  Alessandro Morbidelli,et al.  Accretion of Uranus and Neptune from inward-migrating planetary embryos blocked by Jupiter and Saturn , 2015, 1506.03029.

[39]  Ralf Kotulla,et al.  Interstellar Interloper 1I/2017 U1: Observations from the NOT and WIYN Telescopes , 2017, 1711.05687.

[40]  Gregory Laughlin,et al.  The Feasibility and Benefits of In Situ Exploration of ‘Oumuamua-like Objects , 2018, 1803.07022.

[41]  Z. Sekanina,et al.  Comet Bowell /1980b/ - An active-looking dormant object , 1982 .

[42]  Larry Denneau,et al.  A brief visit from a red and extremely elongated interstellar asteroid , 2017, Nature.

[43]  Robert Jedicke,et al.  Spectroscopy and thermal modelling of the first interstellar object 1I/2017 U1 ‘Oumuamua , 2017, Nature Astronomy.

[44]  A. Moro-Mart'in,et al.  Could 1I/’Oumuamua be an Icy Fractal Aggregate? , 2019, The Astrophysical Journal.

[45]  Thomas A. McGlynn,et al.  On the Nondetection of Extrasolar Comets , 1989 .

[46]  Akihiko Fukui,et al.  THE EXOPLANET MASS-RATIO FUNCTION FROM THE MOA-II SURVEY: DISCOVERY OF A BREAK AND LIKELY PEAK AT A NEPTUNE MASS , 2016 .

[47]  Michael Mommert,et al.  Constraints on the Density and Internal Strength of 1I/’Oumuamua , 2018, 1803.09864.

[48]  Susanne Pfalzner,et al.  Cluster dynamics largely shapes protoplanetary disc sizes , 2016 .

[49]  Sean N. Raymond,et al.  Implications of the interstellar object 1I/'Oumuamua for planetary dynamics and planetesimal formation , 2017, 1711.09599.

[50]  W. C. Danchi,et al.  Incidence of debris discs around FGK stars in the solar neighbourhood , 2016, 1605.05837.

[51]  Rixin Li,et al.  Evidence for Universality in the Initial Planetesimal Mass Function , 2017, 1705.03889.

[52]  Davide Farnocchia,et al.  Non-gravitational acceleration in the trajectory of 1I/2017 U1 (‘Oumuamua) , 2018, Nature.

[53]  R. Rafikov,et al.  Spin Evolution and Cometary Interpretation of the Interstellar Minor Object 1I/2017 ’Oumuamua , 2018, The Astrophysical Journal.

[54]  M. Wyatt,et al.  Evolution of Debris Disks , 2008 .

[55]  Abraham Loeb Six Strange Facts About`Oumuamua , 2018 .

[56]  K. Ulaczyk,et al.  One or more bound planets per Milky Way star from microlensing observations , 2012, Nature.

[57]  Munetaka Ueno,et al.  AKARI NEAR-INFRARED SPECTROSCOPIC SURVEY FOR CO2 IN 18 COMETS , 2012 .

[58]  Lori M. Feaga,et al.  On the Rotation Period and Shape of the Hyperbolic Asteroid 1I/‘Oumuamua (2017 U1) from Its Lightcurve , 2017, 1711.01402.

[59]  Jorge I. Zuluaga,et al.  A General Method for Assessing the Origin of Interstellar Small Bodies: The Case of 1I/2017 U1 (‘Oumuamua) , 2017, 1711.09397.

[60]  Karen J. Meech,et al.  Using Cometary Activity to Trace the Physical and Chemical Evolution of Cometary Nuclei , 2004 .

[61]  B. Moore,et al.  The fate of planetesimal discs in young open clusters: implications for 1I/’Oumuamua, the Kuiper belt, the Oort cloud, and more , 2019, Monthly Notices of the Royal Astronomical Society.

[62]  Qicheng Zhang,et al.  1I/2017 U1 (‘Oumuamua) is Hot: Imaging, Spectroscopy, and Search of Meteor Activity , 2017, 1711.02320.

[63]  Sebastian Kurowski,et al.  Tumbling motion of 1I/‘Oumuamua and its implications for the body’s distant past , 2018, Nature Astronomy.

[64]  Matthew Holman,et al.  Long-Term Stability of Planets in Binary Systems , 1996 .

[65]  Arik W. Mitschang,et al.  The velocity ellipsoid in the Galactic disc using Gaia DR1 , 2017, 1710.08479.

[66]  Philippe Lamy,et al.  Physical Properties of the Nucleus of Comet 2P/Encke , 2000 .

[67]  David G. Schleicher,et al.  THE EXTREMELY ANOMALOUS MOLECULAR ABUNDANCES OF COMET 96P/MACHHOLZ 1 FROM NARROWBAND PHOTOMETRY , 2008 .

[68]  U. Fink,et al.  Comet Yanaka (1988r): A New Class of Carbon-Poor Comet , 1991, Science.

[69]  Petr Pravec,et al.  The asteroid lightcurve database , 2009 .

[70]  G. Domokos,et al.  FORMATION OF SHARP EDGES AND PLANAR AREAS OF ASTEROIDS BY POLYHEDRAL ABRASION , 2009, 0904.4423.

[71]  Michael Marsset,et al.  Col-OSSOS: Colors of the Interstellar Planetesimal 1I/‘Oumuamua , 2017, 1711.06214.

[72]  Luca Ricci,et al.  The Disk Substructures at High Angular Resolution Program (DSHARP). VIII. The Rich Ringed Substructures in the AS 209 Disk , 2018, The Astrophysical Journal.

[73]  T. B. Spahr,et al.  ExploreNEOs. V. AVERAGE ALBEDO BY TAXONOMIC COMPLEX IN THE NEAR-EARTH ASTEROID POPULATION , 2011 .

[74]  Adriana Maras,et al.  Space weathering, reddening and gardening of asteroids: A complex problem , 2007 .

[75]  Sean N. Raymond,et al.  Interstellar Object ’Oumuamua as an Extinct Fragment of an Ejected Cometary Planetesimal , 2018, 1803.02840.

[76]  Marco Micheli,et al.  Inner solar system material discovered in the Oort cloud , 2016, Science Advances.

[77]  M. Ćuk,et al.  1I/‘Oumuamua as a Tidal Disruption Fragment from a Binary Star System , 2017, 1712.01823.

[78]  Mohamad Ali-Dib,et al.  Ejection of rocky and icy material from binary star systems: implications for the origin and composition of 1I/‘Oumuamua , 2017, 1712.04435.

[79]  A. Moro-Mart'in,et al.  Origin of 1I/’Oumuamua. II. An Ejected Exo-Oort Cloud Object? , 2018, The Astronomical Journal.

[80]  Petr Pravec,et al.  The tumbling rotational state of 1I/‘Oumuamua , 2017, Nature Astronomy.

[81]  Konstantin Batygin,et al.  On the Anomalous Acceleration of 1I/2017 U1 ‘Oumuamua , 2019, The Astrophysical Journal.

[82]  P. A. Dybczy'nski,et al.  Investigating the dynamical history of the interstellar object 'Oumuamua , 2017, 1711.06618.

[83]  Elizabeth A. Lada,et al.  Disk Frequencies and Lifetimes in Young Clusters , 2001, astro-ph/0104347.

[84]  Simon Portegies Zwart,et al.  The origin of interstellar asteroidal objects like 1I/2017 U1 , 2017, 1711.03558.

[85]  Hans Rickman,et al.  Nongravitational effects and the aging of periodic comets , 1991 .

[86]  H. J. Rocha-Pinto,et al.  A kinematical age for the interstellar object 1I/’Oumuamua , 2018, Monthly Notices of the Royal Astronomical Society.

[87]  S. Debei,et al.  Size-frequency distribution of boulders ≥7 m on comet 67P/Churyumov-Gerasimenko , 2015 .

[88]  Joshua N. Winn,et al.  The Occurrence and Architecture of Exoplanetary Systems , 2014, 1410.4199.

[89]  Sean N. Raymond,et al.  PLANET–PLANET SCATTERING IN PLANETESIMAL DISKS , 2009, 0905.3741.

[90]  Amir Siraj,et al.  ‘Oumuamua's Geometry Could Be More Extreme than Previously Inferred , 2019, Research Notes of the AAS.

[91]  Alessandro Morbidelli,et al.  Coupling dynamical and collisional evolution of small bodies: an application to the early ejection of planetesimals from the Jupiter-Saturn region , 2003 .

[92]  G. Fazio,et al.  Spitzer Observations of Interstellar Object 1I/‘Oumuamua , 2018, The Astronomical Journal.

[93]  Sebastian Kurowski,et al.  The Excited Spin State of 1I/2017 U1 ‘Oumuamua , 2018, 1804.03471.

[94]  J. I. Katz,et al.  Why is interstellar object 1I/2017 U1 (`Oumuamua) rocky, tumbling and possibly very prolate? , 2018, 1802.02273.

[95]  A. Moro-Mart'in,et al.  Origin of 1I/’Oumuamua. I. An Ejected Protoplanetary Disk Object? , 2018, The Astrophysical Journal.

[96]  James A. Kwiecinski,et al.  Effects of tidal torques on 1I/2017 U1 (‘Oumuamua) , 2018, Icarus.