Investigating the dynamical history of the interstellar object ’Oumuamua

Dybczyński, Piotr A.; Królikowska, Małgorzata

doi:10.1051/0004-6361/201732309

Cited by 24 publications

(27 citation statements)

References 28 publications

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“…Some authors have attempted to identify the star or association from which 1I/'Oumuamua originated, but these studies generally do not take into account the errors in stellar positions, which is the most important source of uncertainty (Dybczyński & Królikowska 2018). Other caveats are that young stellar associations are dispersed over 10's of pc (Gaidos 2018), and that given the typical interstellar distance between encounters, large perpendicular displacements can be produced, making it difficult to predict the result of successive stellar encounters (Zhang 2018).…”

Section: Resulting Mass Densitymentioning

confidence: 99%

Origin of 1I/’Oumuamua. I. An Ejected Protoplanetary Disk Object?

Moro‐Martín

2018

ApJ

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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 whether 1I/'Oumuamua could be representative of this background population of ejected objects. The purpose of the study of its origin is that it could provide information about the building blocks of planets in a size range that remains elusive to observations, helping to constrain planet formation models. We compare the mass density of interstellar objects inferred from its detection to that expected from planetesimal disks under two scenarios: circumstellar disks around single stars and wide binaries, and circumbinary disks around tight binaries. Our study makes use of a detailed study of the PanSTARRS survey volume; takes into account that the contribution from each star to the population of interstellar planetesimals depends on stellar mass, binarity, and planet presence; and explores a wide range of possible size distributions for the ejected planetesimals, based on solar system models and observations of its small-body population. We find that 1I/'Oumuamua is unlikely to be representative of a population of isotropically distributed objects, favoring the scenario that it originated from the planetesimal disk of a young nearby star whose remnants are highly anisotropic. Finally, we compare the fluxes of meteorites and micrometeorites observed on Earth to those inferred from this population of interstellar objects, concluding that it is unlikely that one of these objects is already part of the collected meteorite samples.

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Section: Resulting Mass Densitymentioning

confidence: 99%

Origin of 1I/’Oumuamua. I. An Ejected Protoplanetary Disk Object?

Moro‐Martín

2018

ApJ

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“…N-body effects. Dybczyński & Królikowska (2018) took into account the gravitational interactions of 57 stars in their study of the possible origin of 'Oumuamua (discussed in the next section), although they neglected the (more significant) uncertainties in the stellar astrometry and radial velocities. We explicitly tested the effects of including the gravity of the closest 100 closest encounters to 'Oumuamua (identified from the orbital integration with solution 2 k=2), on the orbits of both 'Oumuamua and the stars.…”

Section: Interaction With a Second Starmentioning

confidence: 99%

“…The difference of about 0.4 • between the purely gravitational solution JPL 13 and 2 k=2 (Figure 1) corresponds to a difference of 0.35 pc after a journey of 50 pc (for linear motions). Dybczyński & Królikowska (2018) compiled data from Simbad, which was mostly TGAS and Hipparcos astrometry, and RAVE-DR4 (Kordopatis et al 2013) and RAVE-DR5 (Kunder et al 2017) radial velocities. They found HIP 3757 to be the closest encounter, with t enc = −0.118 Myr, d enc = 0.0044 pc, v enc = 185 km s −1 , but they sensibly disregarded this as a likely home for 'Oumuamua due to the large encounter velocity.…”

Section: Comparison To Previous Searchesmentioning

confidence: 99%

“…Various attempts have been make to link the trajectory of 'Oumuamua to a star in the vicinity of the solar neighborhood. These studies propagated 'Oumuamua's trajectory out of the solar system on the assumption that this was purely gravitational, then integrated its orbit and those of nearby stars to look for close, low-velocity encounters (Dybczyński & Królikowska 2018;Feng & Jones 2018;Portegies Zwart et al 2018;Zhang 2018;Zuluaga et al 2018). None of them identified a good candidate.…”

Section: Introductionmentioning

confidence: 99%

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Plausible Home Stars of the Interstellar Object ‘Oumuamua Found in Gaia DR2

Bailer‐Jones

Farnocchia

Meech

et al. 2018

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The first detected interstellar object 'Oumuamua that passed within 0.25 au of the Sun on 2017 September 9 was presumably ejected from a stellar system. We use its newly determined non-Keplerian trajectory together with the reconstructed Galactic orbits of 7 million stars from Gaia DR2 to identify past close encounters. Such an "encounter" could reveal the home system from which 'Oumuamua was ejected. The closest encounter, at 0.60 pc (0.53-0.67 pc, 90% confidence interval), was with the M2.5 dwarf HIP 3757 at a relative velocity of 24.7 km s −1 , 1 Myr ago. A more distant encounter (1.6 pc) but with a lower encounter (ejection) velocity of 10.7 km s −1 was with the G5 dwarf HD 292249, 3.8 Myr ago. Two more stars have encounter distances and velocities intermediate to these. The encounter parameters are similar across six different non-gravitational trajectories for 'Oumuamua. Ejection of 'Oumuamua by scattering from a giant planet in one of the systems is plausible, but requires a rather unlikely configuration to achieve the high velocities found. A binary star system is more likely to produce the observed velocities. None of the four home candidates have published exoplanets or are known to be binaries. Given that the 7 million stars in Gaia DR2 with 6D phase space information is just a small fraction of all stars for which we can eventually reconstruct orbits, it is a priori unlikely that our current search would find 'Oumuamua's home star system. As 'Oumuamua is expected to pass within 1 pc of about 20 stars and brown dwarfs every Myr, the plausibility of a home system depends also on an appropriate (low) encounter velocity.

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“…This proportion depends on the threshold used to define the JupiterSaturn barrier. Using 15 AU in both cases yields a proportion of "fake" new comets in the observations sample of around 50% (51% for Dybczyński & Królikowska 2011) and (49% for Dybczyński & Królikowska 2015), and from the simulations, this proportion is about 61% in Fouchard et al (2014) and 55% in Fouchard et al (2017). We still refer for historical reason to these comets as the new long-period comets.…”

Section: Observed Samplesmentioning

confidence: 88%

Distribution of long-period comets: comparison between simulations and observations

Fouchard

Rickman

Froeschlé

et al. 2017

A&A

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Aims. This paper is devoted to a comparison between observations and simulations of the so-called Oort spike formed by the "new" observable long-period comets. Methods. The synthetic distributions of observable comets come from the propagation of a huge sample of objects during the age of the solar system that were initially in a proto-Oort cloud, which was flattened around the ecliptic and had perihelia in the region of Uranus and Neptune. For the known new long-period comets, two samples were used, one that is assumed to be complete, and the comets of the other exclusively come from the Warsaw catalog of comets. The original orbital energy of the comets in this catalog is more reliable. Results. Considering comets with a perihelion distance smaller than 4 AU, for which one of our samples of known comets can be assumed to be complete, the comparison shows small but significant differences in the orbital energy distribution and in the proportion of retrograde comets. When we extend the limiting perihelion distance to 10 AU, the observed samples are obviously strongly incomplete. The synthetic distribution shows that the number of observable comets per year and per perihelion distance unit is ∝q 1.09 for q < 4 AU and ∝q 2.13 for 6 < q < 10 AU. The increase for q > 6 AU comes from comets that were already within the Jupiter-Saturn barrier (q < 15 AU) at their previous perihelion passage (which we call creepers and Kaib and Quinn creepers), with original semi-major axes generally smaller than 20 000 AU. Conclusions. To explain the small but significant differences between our synthetic sample and the known comets for a perihelion distance smaller than 4 AU, different hypotheses are proposed: a still erroneous value of the original orbital energy in the observed sample, a higher density of low-mass stars in the actual solar neighborhood, a ninth planet, and obviously the initial population of objects from which the synthetic distributions are derived.

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Investigating the dynamical history of the interstellar object ’Oumuamua

Cited by 24 publications

References 28 publications

Origin of 1I/’Oumuamua. I. An Ejected Protoplanetary Disk Object?

Origin of 1I/’Oumuamua. I. An Ejected Protoplanetary Disk Object?

Plausible Home Stars of the Interstellar Object ‘Oumuamua Found in Gaia DR2

Distribution of long-period comets: comparison between simulations and observations

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