Study of the Plutino Object (208996) 2003 AZ<sub>84</sub> from Stellar Occultations: Size, Shape, and Topographic Features

Dias-Oliveira, A.; Sicardy, B.; Ortiz, J. L.; Braga-Ribas, F.; Leiva, Rodrigo; Vieira-Martins, R.; Benedetti-Rossi, G.; Camargo, J. I. B.; Assafin, M.; Gomes-Júnior, A. R.; Baug, Tapas; Chandrasekhar, T.; Desmars, J.; Duffárd, R.; Santos-Sanz, P.; Ergang, Z.; Ganesh, S.; Ikari, Y.; Irawati, P.; Jain, Jithesh; Liying, Zhu; Richichi, A.; Shengbang, Qian; Behrend, R.; Benkhaldoun, Z.; Brosch, Noah; Daassou, A.; Frappa, Eric; Gal‐Yam, A.; García-Lozano, Rubén; Gillon, M.; Jehin, Emmanuël; Kaspi, S.; Klotz, A.; Lecacheux, J.; Mahasena, P.; Manfroid, Jean; Manulis, I.; Maury, A.; Mohan, V.; Morales, N.; Ofek, E. O.; Rinner, C.; Sharma, A.; Sposetti, S.; Tanga, P.; Thirouin, A.; Vachier, F.; Widemann, Thomas; Asai, Ayumi; Watanabe, Hayato; Watanabe, Hitoshi; Owada, M.; Yamamura, H.; Hayamizu, Tsutomu; Bradshaw, J.; Kerr, S.; Tomioka, H.; Andersson, S.; Dangl, G.; Haymes, T.; Naves, R.; Wortmann, G.

doi:10.3847/1538-3881/aa74e9

Cited by 36 publications

(13 citation statements)

References 26 publications

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“…Considering this, we also plot all known objects. The observed population is taken from the Minor Planet Center (on 10th October 2017), with measured radii from occulations (Elliot et al 2010;Sicardy et al 2011;Braga-Ribas et al 2013;Alvarez-Candal et al 2014;Dias-Oliveira et al 2017;Schindler et al 2017), direct imaging (Nimmo et al 2017), thermal modelling (Lim et al 2010;Müller et al 2010;Mommert et al 2012;Pál et al 2012;Santos-Sanz et al 2012;Vilenius et al 2012;Fornasier et al 2013;Lellouch et al 2013;Vilenius et al 2014), or by assuming albedos of (D/250 km) 2 + 6 % per Fraser et al (2014), in that order of priority. Masses for objects with satellites were taken from Benecchi et al (2010); Brown (2013); Brown & Schaller (2007); Carry et al (2011);Fraser et al (2013); Grundy et al (2007Grundy et al ( , 2008Grundy et al ( , 2009Grundy et al ( , 2011Grundy et al ( , 2012Grundy et al ( , 2015; Kovalenko et al (2017); Margot et al (2004); Parker et al (2011); Ragozzine & Brown (2009);Sheppard, Ragozzine & Trujillo (2012); Stansberry et al (2012); Stern et al (2015); Veillet et al (2002).…”

Section: Observations and Our Inferences Of The Pastmentioning

confidence: 99%

Limits on the number of primordial Scattered disc objects at Pluto mass and higher from the absence of their dynamical signatures on the present-day trans-Neptunian Populations

Shannon

Dawson

2018

Monthly Notices of the Royal Astronomical Society

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Today, Pluto and Eris are the largest and most massive Trans-Neptunian Objects respectively. They are believed to be the last remnants of a population of planetesimals that has been reduced by > 99% since the time of its formation. This reduction implies a primordial population of hundreds or thousands of Pluto-mass objects, and a mass-number distribution that could have extended to hundreds of Lunas, dozens of Mars, and several Earths. Such lost protoplanets would have left signatures in the dynamics of the present-day Trans-Neptunian Populations, and we statistically limit their primordial number by considering the survival of ultra-wide binary TNOs, the Cold Classical Kuiper belt, and the resonant population. We find that if the primordial mass-number distribution extended to masses greater than Pluto ∼ 10 −3 M ⊕ , it must have turned downwards to be no more top-heavy than roughly equal mass per log size, a significant deviation from the distribution observed between 10 −5 M ⊕ and 10 −3 M ⊕ . We compare these limits to the predicted mass-number distribution of various planetesimal and proto-planet growth models. The limits derived here provide a test for future models of planetesimal formation.

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Section: Observations and Our Inferences Of The Pastmentioning

confidence: 99%

Limits on the number of primordial Scattered disc objects at Pluto mass and higher from the absence of their dynamical signatures on the present-day trans-Neptunian Populations

Shannon

Dawson

2018

Monthly Notices of the Royal Astronomical Society

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“…Although young, this field of work is quickly evolving and it is an essential one if we want to adequately characterize and understand the physical properties of the TNO population as a whole. This is because stellar occultations can provide extremely relevant information such as very accurate sizes and shapes, better than any other technique can do (except for spacecraft visits, which Besides, shapes derived from the occultations can be used to determine densities under the assumption of hydrostatic equilibrium of a homogeneous body, provided that the spin rate is known and some constraint on the spin axis orientation is used (Sicardy et al 2011, Braga-Ribas et al 2013, Benedetti-Rossi 2016, Schindler et al 2017, Dias-Oliveira et al 2017. Nevertheless, at least for the case of Haumea this approach fails to derive the actual density ).…”

Section: Introductionmentioning

confidence: 99%

Stellar occultations by Trans-Neptunian objects: From predictions to observations and prospects for the future

Ortiz

Sicardy

Camargo

et al. 2020

The Trans-Neptunian Solar System

113

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In terms of scientific output, the best way to study solar system bodies is sending spacecraft to make in-situ measurements or to observe at close distance. Probably, the second best means to learn about important physical properties of solar system objects is through stellar occultations. By combining occultation observations from several sites, size and shape can be derived with kilometric accuracy. Also, atmospheric properties can be derived if the body has an atmosphere. Furthermore, the technique can detect rings and even satellites (although rarely) around the main body. Except for the very special cases of Pluto and Charon, stellar occultations by Transneptunian Objects (TNOs) had never been observed until October 2009. This was because the ephemeris of the TNOs have much larger uncertainties than their angular diameters (typically of the order of ~10 milliarcsecond) and also because stellar catalogs were not accurate to the milliarcsecond level. Despite the difficulties, at the time of this writing, 43 occultations by 22 different Trans-Neptunian Objects, and 17 occultations by 5 Centaurs have been detected thanks to the efforts of several teams. Due to the complications of accurately predicting and observing these events, most of the successes have been achieved through wide international collaboration, which is a key issue to succeed in observing stellar occultations by TNOs. Multichord occultations are typically detected at a rate of ~3 per year on average, whereas the majority of the observed occultations are single-chord detections, which means that only one site detects the occultation. In these cases, no tight constraints on size and shape can be derived from those observations alone. Here we review most of the aspects involved in the complex process to successfully observe occultations, and present some of the lessons learned. There are good prospects for the future if we take advantage of the stellar catalog from the Gaia Data Release 2 and if we take advantage of dedicated observational programs of TNOs, to improve their orbits to the required level of accuracy, which is a critical aspect. All this, in combination with large and optimized telescope networks may allow an increase in the success rate and scientific output of the occultation technique applied to TNOs, in the short-term future.are extremely expensive, complex and require a lot of time). Size and shape are basic physical parameters that must be accurately known if we want to fully characterize a body, and are the first step toward deriving accurate densities. We need to know densities if we aim to determine internal compositions and make first guesses on the internal structure of solar system bodies (Carry et al. 2012).On the other hand, once size and shape are correctly determined for a solar system body, combining this information with accurate brightness measurements allows deriving accurate geometric albedos, which are also an important piece of information to properly interpret many of the visible light observations of the TNOs,...

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“…Stellar occultations provide by far the most accurate method, whereby multiple chords with kilometric accuracy, combined with lightcurve information, may yield three-dimensional shapes and even topography (e.g. Dias-Oliveira et al, 2017). For objects with known mass (i.e.…”

Section: Introductionmentioning

confidence: 99%

The thermal emission of Centaurs and trans-Neptunian objects at millimeter wavelengths from ALMA observations

Lellouch

Moreno

Müller

et al. 2017

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The sensitivity of ALMA makes it possible to detect thermal mm/submm emission from small and/or distant Solar System bodies at the sub-mJy level. While the measured fluxes are primarily sensitive to the objects' diameters, deriving precise sizes is somewhat hampered by the uncertain effective emissivity at these wavelengths. Following the work of Brown and Butler (2017) who presented ALMA data for four TNOs with satellites, we report on ALMA 233 GHz (1.29 mm) flux measurements of four Centaurs (2002 GZ 32 , Bienor, Chiron, Chariklo) and two TNOs (Huya and Makemake), sampling a range of size, albedo and composition. These thermal fluxes are combined with previously published fluxes in the mid/far-infrared in order to derive their relative emissivity at radio (mm/submm) wavelengths, using NEATM and thermophysical models. We reassess earlier thermal measurements of these and other objects -including Pluto/Charon and Varuna -exploring in particular effects due to non-spherical shape and varying apparent pole orientation whenever information is available, and show that these effects can be key for reconciling previous diameter determinations and correctly estimating the spectral emissivities. We also evaluate the possible contribution to thermal fluxes of established (Chariklo) or claimed (Chiron) ring systems. For Chariklo, the rings do not impact the diameter determinations by more than ∼5 %; for Chiron, invoking a ring system does not help in improving the consistency between the numerous past size measurements. As a general conclusion, all the objects, except Makemake, have radio emissivities significantly lower than unity. Although the emissivity values show diversity, we do not find any significant trend with physical parameters such as diameter, composition, beaming factor, albedo, or color, but we suggest that the emissivity could be correlated with grain size. The mean relative radio emissivity is found to be 0.70±0.13, a value that we recommend for the analysis of further mm/submm data.

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Study of the Plutino Object (208996) 2003 AZ₈₄ from Stellar Occultations: Size, Shape, and Topographic Features

Cited by 36 publications

References 26 publications

Limits on the number of primordial Scattered disc objects at Pluto mass and higher from the absence of their dynamical signatures on the present-day trans-Neptunian Populations

Limits on the number of primordial Scattered disc objects at Pluto mass and higher from the absence of their dynamical signatures on the present-day trans-Neptunian Populations

Stellar occultations by Trans-Neptunian objects: From predictions to observations and prospects for the future

The thermal emission of Centaurs and trans-Neptunian objects at millimeter wavelengths from ALMA observations

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Study of the Plutino Object (208996) 2003 AZ84 from Stellar Occultations: Size, Shape, and Topographic Features

Cited by 36 publications

References 26 publications

Limits on the number of primordial Scattered disc objects at Pluto mass and higher from the absence of their dynamical signatures on the present-day trans-Neptunian Populations

Limits on the number of primordial Scattered disc objects at Pluto mass and higher from the absence of their dynamical signatures on the present-day trans-Neptunian Populations

Stellar occultations by Trans-Neptunian objects: From predictions to observations and prospects for the future

The thermal emission of Centaurs and trans-Neptunian objects at millimeter wavelengths from ALMA observations

Contact Info

Product

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Study of the Plutino Object (208996) 2003 AZ₈₄ from Stellar Occultations: Size, Shape, and Topographic Features