On the Rotation Period and Shape of the Hyperbolic Asteroid 1I/‘Oumuamua (2017 U1) from Its Lightcurve

Knight, Matthew M.; Protopapa, S.; Kelley, Michael S. P.; Farnham, T. L.; Bauer, J. M.; Bodewits, Dennis; Feaga, Lori M.; Sunshine, J. M.

doi:10.3847/2041-8213/aa9d81

Cited by 63 publications

(55 citation statements)

References 22 publications

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“…Shepard et al 2017). With the observed dimensions of a cylinder of 25 × 230 m (Knight et al 2017), we arrive at a mass of m 1.2 × 10 9 kg. A hypothetical young Solar system could then have ejected 3.3 × 10 16 objects during its early evolution, leading to a mean density of ∼ 3.9 × 10 15 pc −3 , exceeding our observational estimate by a factor of ∼ 6.…”

Section: Origin From the Oort Cloud Of Another Starmentioning

confidence: 88%

The origin of interstellar asteroidal objects like 1I/2017 U1 ‘Oumuamua

Zwart

Torres

Pelupessy

et al. 2018

Monthly Notices of the Royal Astronomical Society: Letters

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We study the origin of the interstellar object 1I/2017 U1 'Oumuamua by juxtaposing estimates based on the observations with simulations. We speculate that objects like 'Oumuamua are formed in the debris disc as left over from the star and planet formation process, and subsequently liberated. The liberation process is mediated either by interaction with other stars in the parental star-cluster, by resonant interactions within the planetesimal disc or by the relatively sudden mass loss when the host star becomes a compact object. Integrating 'Oumuamua backward in time in the Galactic potential together with stars from the Gaia-TGAS catalogue we find that about 1.3 Myr ago 'Oumuamua passed the nearby star HIP 17288 within a mean distance of 1.3 pc. By comparing nearby observed L-dwarfs with simulations of the Galaxy we conclude that the kinematics of 'Oumuamua is consistent with relatively young objects of 1.1-1.7 Gyr. We just met 'Oumuamua by chance, and with a derived mean Galactic density of ∼ 3 × 10 5 similarly sized objects within 100 au from the Sun or ∼ 10 14 per cubic parsec we expect about 2 to 12 such visitors per year within 1 au from the Sun.

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Section: Origin From the Oort Cloud Of Another Starmentioning

confidence: 88%

The origin of interstellar asteroidal objects like 1I/2017 U1 ‘Oumuamua

Zwart

Torres

Pelupessy

et al. 2018

Monthly Notices of the Royal Astronomical Society: Letters

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“…The discovery of the second-ever interstellar object comet 2I/Borisov on 2019 August 30, (MPEC 2019-R106) presents a unique opportunity to contrast planetesimal formation in our Solar System with formation processes in other stellar systems-in a way not possible with the first interstellar object found, 1I/'Oumuamua. ʻOumuamua, is red with a pronounced elongation (Meech et al, 2017;Knight et al, 2017;Ye et al, 2018;Trilling et al, 2018) with an assumed low, but undetermined, visible (< 0.15) and infrared (< 0.2) albedo Trilling et al, 2018) in a non-principal axis ("tumbling") rotational state (Drahus et al, 2018;Fraser et al, 2018, Belton et al, 2018, and strong evidence for nongravitational acceleration (Micheli et al, 2018). No gas emissions were detected from 'Oumuamua: chemical analyses were limited to observing its surface reflectivity and are consistent with an outer Solar System body with appreciable organic content.…”

Section: Introductionmentioning

confidence: 99%

Carbon Chain Depletion of 2I/Borisov

Kareta¹,

Andrews²,

Noonan³

et al. 2020

ApJL

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The composition of comets in the Solar System come in multiple groups thought to encode information about their formation in different regions of the outer protosolar disk. The recent discovery of the second interstellar object, 2I/Borisov, allows for spectroscopic investigations into its gas content and a preliminary classification of it within the Solar System comet taxonomies to test the applicability of planetesimal formation models to other stellar systems. We present spectroscopic and imaging observations from 2019 September 20th through October 26th from the Bok, MMT, and LBT telescopes. We identify CN in the comet's spectrum and set precise upper limits on the abundance of C2 on all dates. We use a Haser model to convert our integrated fluxes to production rates and find Q(CN) = 5.0 +/-2.0 * 10^24 mol/s on September 20 th and Q(CN) = (1.1 -1.9) * 10^24 mols/s on later dates, both consistent with contemporaneous observations. We set our lowest upper limit on a C2 production rate, Q(C2) < 1.6 10^23 mols/s on October 10th. The measured ratio upper limit for that date Q(C2)/Q(CN) < 0.095 indicates that 2I/Borisov is strongly in the (carbon chain) 'depleted' taxonomic group. The only comparable Solar System comets have detected ratios near this limit, making 2I/Borisov statistically likely to be more depleted than any known comet. Most 'depleted' comets are Jupiter Family Comets, perhaps indicating a similarity in formation conditions between the most depleted of the JFCs and 2I/Borisov. More work is needed to understand the applicability of our knowledge of Solar System comet taxonomies onto interstellar objects and we discuss future work that could help to clarify the usefulness of the approach.

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“…Spectroscopic results [12,13,[17][18][19][20][21] indicate that the object is reddish, with a distribution similar to Trans-Neptunian objects [18,19,21]. The rapidly changing albedo has also lead to the assumption that the object is rotating and is highly elongated [19,22,23] with estimated dimensions of 230m x 35m x 35m [21]. The axis ratio of ≥ 6.3 .…”

Section: Introductionmentioning

confidence: 99%

Project Lyra: Sending a spacecraft to 1I/’Oumuamua (former A/2017 U1), the interstellar asteroid

Hein¹,

Perakis²,

Eubanks³

et al. 2019

Acta Astronautica

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The first definitely interstellar object 1I/'Oumuamua (previously A/2017 U1) observed in our solar system provides the opportunity to directly study material from other star systems. Can such objects be intercepted? The challenge of reaching the object within a reasonable timeframe is formidable due to its high heliocentric hyperbolic excess velocity of about 26 km/s; much faster than any vehicle yet launched. This paper presents a high-level analysis of potential near-term options for a mission to 1I/'Oumuamua and potential similar objects. Launching a spacecraft to 1I/'Oumuamua in a reasonable timeframe of 5-10 years requires a hyperbolic solar system excess velocity between 33 to 76 km/s for mission durations between 30 to 5 years. Different mission durations and their velocity requirements are explored with respect to the launch date, assuming direct impulsive transfer to the intercept trajectory. For missions using a powered Jupiter flyby combined with a solar Oberth maneuver using solid rocket boosters and Parker Solar Probe heatshield technology, a Falcon Heavy-class launcher would be able to launch a spacecraft of dozens of kilograms towards 1I/'Oumuamua, if launched in 2021. An additional Saturn flyby would allow for the launch of a New Horizons-class spacecraft. Further technology options are outlined, ranging from electric propulsion, and more advanced options such as laser electric propulsion, and solar and laser sails. To maximize science return decelerating the spacecraft at 'Oumuamua is highly desirable, due to the minimal science return from a hyper-velocity encounter. Electric and magnetic sails could be used for this purpose. It is concluded that although reaching the object is challenging, there seem to be feasible options based on current and nearterm technology.

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On the Rotation Period and Shape of the Hyperbolic Asteroid 1I/‘Oumuamua (2017 U1) from Its Lightcurve

Cited by 63 publications

References 22 publications

The origin of interstellar asteroidal objects like 1I/2017 U1 ‘Oumuamua

The origin of interstellar asteroidal objects like 1I/2017 U1 ‘Oumuamua

Carbon Chain Depletion of 2I/Borisov

Project Lyra: Sending a spacecraft to 1I/’Oumuamua (former A/2017 U1), the interstellar asteroid

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