PDKEEPAAA（229762）2007 UK $_{126}$ 2014年11月15日多弦恒星掩星结果
Results from the 2014 November 15th multi-chord stellar occultation by the TNO (229762) 2007 UK$_{126}$
Gustavo Benedetti-Rossi, Bruno Sicardy, Marc W. Buie, Jose L. Ortiz, Roberto Vieira-Martins, John M. Keller, Felipe Braga-Ribas, Julio I. B. Camargo, Marcelo As… 展开作者
Gustavo Benedetti-Rossi, Bruno Sicardy, Marc W. Buie, Jose L. Ortiz, Roberto Vieira-Martins, John M. Keller, Felipe Braga-Ribas, Julio I. B. Camargo, Marcelo Assafin, Nicolas Morales, Rene Duffard, Alex Dias-Oliveira, Pablo Santos-Sanz, Josselin Desmars, Altair R. Gomes-Junior, Rodrigo Leiva, Jerry Bardecker, Jim K. Jr. Bean, Aart M. Olsen, Daniel W. Ruby, Red Sumner, Audrey Thirouin, Marco A. Gomez-Munoz, Leonel Gutierrez, Larry Wasserman, David Charbonneau, Jonathan Irwin, Stephen Levine, Brian Skiff
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40 pages, 5 figures, 4 tables. Accepted for publication in the The Astronomical Journal (Aug. 1, 2016)
We present results derived from the first multi-chord stellar occultation by the trans-Neptunian object (229762) 2007 UK$_{126}$, observed on 2014 November 15. The event was observed by the Research and Education Collaborative Occultation Network (RECON) project and International Occultation Timing Association (IOTA) collaborators throughout the United States. Use of two different data analysis methods obtain a satisfactory fit to seven chords, yelding an elliptical fit to the chords with an equatorial radius of $R=338_{-10} ^{+15}$ km and equivalent radius of $R_{eq}=319_{-7} ^{+14}$ km. A circular fit also gives a radius of $R=324_{-23} ^{+30}$ km. Assuming that the object is a Maclaurin spheroid with indeterminate aspect angle, and using two published absolute magnitudes for the body, we derive possible ranges for geometric albedo between $p_{V}=0.159_{-0.013} ^{+0.007}$ and $p_{R}=0.189_{-0.015}^{+0.009}$, and for the body oblateness between $ε=0.105_{-0.040} ^{+0.050}$ and $ε=0.118_{-0.048} ^{+0.055}$. For a nominal rotational period of 11.05 h, an upper limit for density of $ρ=1740$ kg~m$^{-3}$ is estimated for the body.
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 v…
Investigating the formation of small Solar System objects using stellar occultations by satellites: present, future and its use to update satellite orbits
Transneptunian objects (TNOs) are a source of invaluable information to access the history and evolution of the outer solar system. However, observing these faint objects is a difficult task. As a consequence, important properties such as size and albedo are known for only a small fraction of them. Now, with the results from deep sky surveys and the Gaia space mission, a new exciting era is within reach as accurate predictions of stellar occultations by numerous distant small solar system bodies become available. From them, diameters with kilometer accuracies can be determined. Albedos, in tur…
Within our international program to obtain accurate physical properties of trans-Neptunian objects (TNOs) we predicted a stellar occultation by the TNO (38628) Huya of the star Gaia DR2 4352760586390566400 (mG = 11.5 mag.) for March 18, 2019. After an extensive observational campaign, we updated the prediction and it turned out to be favorable to central Europe. Therefore, we mobilized half a hundred professional and amateur astronomers, and the occultation was finally detected from 21 telescopes located at 18 sites. This makes the Huya event one of the best ever observed stellar occultation b…
We present results from three world-wide campaigns that resulted in the detections of two single-chord and one multi-chord stellar occultations by the Plutino object (84922) 2003~VS$_2$. From the single-chord occultations in 2013 and 2014 we obtained accurate astrometric positions for the object, while from the multi-chord occultation on November 7th, 2014, we obtained the parameters of the best-fitting ellipse to the limb of the body at the time of occultation. We also obtained short-term photometry data for the body in order to derive its rotational phase during the occultation. The rotation…
A stellar occultation by the extreme large-perihelion trans-Neptunian object (541132) Leleākūhonua (also known by the provisional designation of 2015 TG387) was predicted by the Lucky Star project and observed with the Research and Education Collaborative Occultation Network on 2018 October 20 UT. A single detection and a nearby nondetection provide constraints for the size and albedo. When a circular profile is assumed, the radius is $r={110}_{-10}^{+14}$ km, corresponding to a geometric albedo ${p}_{V}={0.21}_{-0.05}^{+0.03}$, for an adopted absolute magnitude of H V = 5.6, typical of other …
Physical Characterization of Asteroid (16583) Oersted Combining Stellar Occultation and Photometric Data
Charles University, Faculty of Mathematics and Physics, Institute of Astronomy（查理大学数学物理学院天体物理研究所）；Université Côte d’Azur, CNRS-Lagrange, Observatoire de la Côte d’Azur（蔚蓝海岸大学法国国家科学研究中心拉格朗日实验室蔚蓝海岸天文台）；School of Physics and Astronomy, University of Leicester（莱斯特大学物理与天文学院）；Department of Physics, The Catholic University of America（美国天主教大学物理系）；Astrophysics Science Division, NASA Goddard Space Flight Center（NASA戈达德太空飞行中心天体物理学科学部）；Center for Research and Exploration in Space Science and Technology, NASA/GSFC（NASA/戈达德太空飞行中心空间科学与技术研究探索中心）；SETI Institute, Carl Sagan Center（SETI研究所卡尔·萨根中心）；Unistellar
We report six stellar occultations by (Saturn IX) Phoebe, an irregular satellite of Saturn, obtained between mid-2017 and mid-2019. The 2017 July 06 event is the first stellar occultation by an irregular satellite ever observed. The occultation chords were compared to a 3D shape model of the satellite obtained from Cassini observations. The rotation period available in the literature led to a sub-observer point at the moment of the observed occultations where the chords could not fit the 3D model. A procedure was developed to identify the correct sub-observer longitude. It allowed us to obtain…
Trans-Neptunian objects (TNOs) and Centaurs are remnants of our planetary system formation, and their physical properties have invaluable information for evolutionary theories. Stellar occultation is a ground-based method for studying these small bodies and has presented exciting results. These observations can provide precise profiles of the involved body, allowing an accurate determination of its size and shape. The goal is to show that even single-chord detections of TNOs allow us to measure their milliarcsecond astrometric positions in the reference frame of the Gaia second data release (D…
A stellar occultation by Vanth, a satellite of (90482) Orcus
South African Astronomical Observatory（南非天文台）；Massachusetts Institute of Technology（麻省理工学院）；Lowell Observatory（洛厄尔天文台）；University of Cape Town（开普敦大学）；Universität Stuttgart（斯图加特大学）；Deutsches SOFIA Institut, Universität Stuttgart（德国SOFIA研究所，斯图加特大学）；SOFIA Science Center, NASA Ames Research Center（NASA艾姆斯研究中心SOFIA科学中心）；Las Cumbres Observatory（拉斯坎布雷斯天文台）
Within our program of physical characterization of trans-Neptunian objects and centaurs, we predicted a stellar occultation by the centaur (54598) Bienor to occur on January 11, 2019, with good observability potential. We obtained high accuracy astrometric data to refine the prediction, resulting in a shadow path favorable for the Iberian Peninsula. This encouraged us to carry out an occultation observation campaign that resulted in five positive detections from four observing sites. This is the fourth centaur for which a multichord (more than two chords) stellar occultation has been observed …
On 28th January 2018, the large Trans-Neptunian Object (TNO) 2002TC302 occulted a m$_v= $15.3 star with ID 130957813463146112 in the Gaia DR2 stellar catalog. 12 positive occultation chords were obtained from Italy, France, Slovenia and Switzerland. Also, 4 negative detections were obtained near the north and south limbs. This represents the best observed stellar occultation by a TNO other than Pluto, in terms of the number of chords published thus far. From the 12 chords, an accurate elliptical fit to the instantaneous projection of the body, compatible with the near misses, can be obtained. …
We present results from the first recorded stellar occultation by the large trans-Neptunian object (174567) Varda that was observed on September 10$^{\rm th}$, 2018. Varda belongs to the high-inclination dynamically excited population, and has a satellite, Ilmarë, which is half the size of Varda. We determine the size and albedo of Varda and constrain its 3D shape and density. Thirteen different sites in the USA monitored the event, five of which detected an occultation by the main body. A best-fitting ellipse to the occultation chords provides the instantaneous limb of the body, from which th…
Constraining the size, shape, and albedo of the large Trans-Neptunian Object (28978) Ixion with multi-chord stellar occultations
Instituto de Astrofísica de Andalucía, IAA-CSIC（安达卢西亚天体物理研究所）；LIRA, CNRS UMR8254, Observatoire de Paris（巴黎天文台）；Federal University of Technology – Paraná (PPGFA/UTFPR)（巴拉那联邦技术大学）；Laboratório Interinstitucional de e-Astronomia (LIneA)（跨机构电子天文学实验室）；Observatório Nacional (MCTI)（国家天文台）；LTE, Observatoire de Paris, Université PSL, Sorbonne Université, Université de Lille, LNE, CNRS（巴黎天文台）；Türkiye National Observatories, TUG（土耳其国家天文台）；The Scientific and Technological Research Council of Türkiye (TÜBİTAK)（土耳其科学与技术研究委员会）；naXys, Department of Mathematics, University of Namur（南纳慕尔大学）；Federal University of Rio de Janeiro - Observatory of Valongo（里约热内卢联邦大学瓦隆戈天文台）；Instituto de Física, Universidade Federal de Uberlândia（乌贝兰迪亚联邦大学物理研究所）；UNESP – São Paulo State University, Grupo de Dinâmica Orbital e Planetologia（圣保罗州立大学）；Institut Polytechnique des Sciences Avancées (IPSA)（高级科学理工学院）；Deutsches Zentrum für Astrophysik (DZA)（德国天体物理学中心）；Florida Space Institute, University of Central Florida（中佛罗里达大学佛罗里达太空研究所）；Department of Space Sciences and Technologies, Akdeniz University（安塔利亚大学空间科学与技术系）；Trans-Tasman Occultation Alliance (TTOA)（跨塔斯曼掩食联盟）；Institute of Astronomy and Astrophysics, University of Tübingen（蒂宾根大学天体物理学与天文学研究所）
The trans-Neptunian object (119951) 2002 KX14 revealed via multiple stellar occultations
Instituto de Astrofísica de Andalucía – Consejo Superior de Investigaciones Científicas (IAA-CSIC)（安达卢西亚天体物理研究所 - 西班牙国家研究委员会）；Florida Space Institute（佛罗里达空间研究所）；Federal University of Technology - Paraná (UTFPR/PPGFA)（巴拉那联邦技术大学）；Laboratório Interinstitucional de e-Astronomia (LIneA/INCT do e-Universo)（跨机构电子天文学实验室）；Observatoire de Paris, Université PSL, Sorbonne Université, Université de Lille, LNE,CNRS（巴黎天文台，PSL大学，索邦大学，里尔大学，法国国家科学研究中心）
Equilibrium figure of Haumea and possible detection by stellar occultation
Université Paris Cité, CNRS, Institut de Physique du Globe de Paris（巴黎西大、法国国家科学研究中心、巴黎地球物理研究所）；Sorbonne Université, Observatoire de Paris, Université PSL, CNRS, Laboratoire Temps Espace（索邦大学、巴黎天文台、巴黎文理研究大学、法国国家科学研究中心、时空实验室）；Université de Lyon, CNRS, ENS Lyon, Laboratoire de Géologie de Lyon Terre - Planètes - Environnement（里昂大学、法国国家科学研究中心、里昂高等师范学校、里昂地质实验室地球-行星-环境）；Jet Propulsion Laboratory, California Institute of Technology（喷气推进实验室、加州理工学院）
Context: Occultations of stars by asteroids are an efficient method to study the properties of minor bodies, and can be exploited as tools to derive very precise asteroid astrometry relative to the target star. With the availability of stellar astrometry thanks to the ESA mission Gaia, the frequency of good predictions and the quality of the astrometry have been strongly enhanced. Aims: Our goal is to evaluate the astrometric performance of a systematic exploitation of stellar occultations, with a homogeneous data set and a given instrument setup. As a reference instrument, we adopt the exampl…
We report observations of a stellar occultation by the classical Kuiper belt object (50000) Quaoar occurred on 28 June 2019. A single-chord high-cadence (2 Hz) photometry dataset was obtained with the Tomo-e Gozen CMOS camera mounted on the 1.05 m Schmidt telescope at Kiso Observatory. The obtained ingress and egress data do not show any indication of atmospheric refraction and allow to set new $1σ$ and $3σ$ upper limits of 6 and 16 nbar, respectively, for the surface pressure of a pure methane atmosphere. These upper limits are lower than the saturation vapor pressure of methane at Quaoar's e…
In 2019, the Research and Education Collaborative Occultation Network (RECON) obtained multiple-chord occultation measurements of two centaur objects: 2014 YY$_{49}$ on 2019 January 28 and 2013 NL$_{24}$ on 2019 September 4. RECON is a citizen-science telescope network designed to observe high-uncertainty occultations by outer solar system objects. Adopting circular models for the object profiles, we derive a radius $r=16^{+2}_{-1}$km and a geometric albedo $p_V=0.13^{+0.015}_{-0.024}$ for 2014 YY$_{49}$, and a radius $r=66 ^{+5}_{-5}$km and geometric albedo $p_V = 0.045^{+0.006}_{-0.008}$ for…
We predicted a stellar occultation of the bright star Gaia DR1 4332852996360346368 (UCAC4 385-75921) (m$_{\rm V}$= 14.0 mag) by the centaur 2002 GZ$_{32}$ for 2017 May 20$^{\rm th}$. Our latest shadow path prediction was favourable to a large region in Europe. Observations were arranged in a broad region inside the nominal shadow path. Series of images were obtained with 29 telescopes throughout Europe and from six of them (five in Spain and one in Greece) we detected the occultation. This is the fourth centaur, besides Chariklo, Chiron and Bienor, for which a multi-chord stellar occultation i…
Context. Bright stellar positions are now known with an uncertainty below 1 mas thanks to Gaia DR2. Between 2019-2020, the Galactic plane will be the background of Jupiter. The dense stellar background will lead to an increase in the number of occultations, while the Gaia DR2 catalogue will reduce the prediction uncertainties for the shadow path. Aims. We observed a stellar occultation by the Galilean moon Europa (J2) and propose a campaign for observing stellar occultations for all Galilean moons. Methods. During a predicted period of time, we measured the light flux of the occulted star and …
Probing close-in satellites of Trans-Neptunian Objects through thermal and direct size measurements
Instituto de Astrofísica de Andalucía, IAA-CSIC（安达卢西亚天体物理研究所）；Deutsches Zentrum für Astrophysik (DZA)（德国天体物理学中心）；Max-Planck-Institut für extraterrestrische Physik（马克斯·普朗克地外物理学研究所）
Stellar occultation is a powerful technique that allows the determination of some physical parameters of the occulting object. The result depends on the photometric accuracy, the temporal resolution, and the number of chords obtained. Space telescopes can achieve high photometric accuracy as they are not affected by atmospheric scintillation. Using ESA's CHEOPS space telescope, we observed a stellar occultation by the Transneptunian object (50000) Quaoar. We compare the obtained chord with previous occultations by this object and determine its astrometry with sub-milliarcsecond precision. Also…
We report observations of a stellar occultation by Pluto on 2019 July 17. A single-chord high-speed (time resolution $= 2\,$s) photometry dataset was obtained with a CMOS camera mounted on the Tohoku University 60 cm telescope (Haleakala, Hawaii). The occultation light curve is satisfactorily fitted to an existing Pluto's atmospheric model. We find the lowest pressure value at a reference radius of $r = 1215~{\rm km}$ among those reported after 2012, indicating a possible rapid (approximately $21^{+4}_{-5} \%$ of the previous value) pressure drop between 2016 (the latest reported estimate) and…
Reconciling results of 2019 and 2020 stellar occultations on Pluto's atmosphere. New constraints from both the 5 September 2019 event and consistency analysis
We predicted, observed, and analyzed the multichord stellar occultation of the Second Gaia Data Release (Gaia DR2) source 3449076721168026624 (m$_v$ = 14.1 mag) by the plutino object 2003 VS$_2$ (hereafter, VS$_2$) on 2019 October 22. We also carried out photometric observations to derive the rotational light curve amplitude and rotational phase of VS$_2$ during the stellar occultation. Combining the results and assuming a triaxial shape, we derived the 3D shape of VS$_2$. Out of the 39 observatories involved in the observational campaign, 12 sites reported a positive detection; this makes it …
The centaur (2060) Chiron has exhibited outgassing behaviour and possibly hosts a ring system. On 2011 November 29, Chiron occulted a fairly bright star (R approximately 15 mag) as observed from the 3-m NASA Infrared Telescope Facility (IRTF) on Mauna Kea and the 2-m Faulkes Telescope North (FTN) at Haleakala. Data were taken as visible wavelength images and simultaneous, low-resolution, near-infrared (NIR) spectra. Here, we present a detailed examination of the light-curve features in the optical data and an analysis of the near-infrared spectra. We place a lower limit on the diameter of Chir…
Size, atmospheric, and ring constraints on the large Kuiper belt object (55565) Aya from a stellar occultation
National Astronomical Observatory of Japan（日本国立天文台）；Ishigakijima Astronomical Observatory, Public Relations Center, National Astronomical Observatory of Japan（日本国立天文台石垣岛天文台公共关系中心）；Department of Physics, Kurume University, School of Medicine（久留米大学医学部物理系）；Institute of Astronomy, Graduate School of Science, The University of Tokyo（东京大学理学研究科天文学研究所）；University of Occupational and Environmental Health, Japan（日本职业环境健康大学）；Planetary Exploration Research Center, Chiba Institute of Technology（千叶工业大学行星探索研究中心）；Saga Hoshizora Astronomy Center（佐贺星空天文中心）；Kyoto Sangyo University, Koyama Space Science Institute（京都产业大学小山宇宙科学研究所）
Pluto's atmosphere from the 29 June 2015 ground-based stellar occultation at the time of the New Horizons flyby
我们提出了2015年6月29日从新西兰和澳大利亚观测到的多弦冥王星掩星的结果。这是在美国宇航局新视野号飞越冥王星系统前两周发生的，可以作为地面和空间结果之间的有用比较。我们发现冥王星的大气层仍在膨胀，自2013年以来压力显著增加了5 $\pm$ 2\%，自1988年以来几乎增加了3倍。这一趋势排除了，截至今天，与冥王星从太阳衰退有关的大气崩溃。在新西兰的几个地点观测到了罕见的中心闪光。闪光的形状和幅度与一个厚度约3 km的球形透明大气层相一致，该大气层的底部位于冥王星表面上方约4 km处，平均温度梯度约为5 K km $^{-1}$。我们讨论的可能性，观测到的和建模的闪光之间的小偏差是由当地的地形特征（山脉）沿冥王星的肢体，阻止恒星光。最后，利用两种可能的温度分布，从我们的最深可达水平向下外推到表面的压力分布，我们得到了表面压力的可能范围为11.9-13.7~ $μ$ bar。
Changes in Pluto's Atmosphere Based on Stellar Occultation Data from 2017 to 2023
Planetary Science Institute（行星科学研究所）；Massachusetts Institute of Technology（麻省理工学院）；Lowell Observatory（洛厄尔天文台）；Universität Stuttgart（斯图加特大学）；SOFIA Science Center NASA Ames Research Center（NASA艾姆斯研究中心索菲亚科学中心）；Las Cumbres Observatory（拉斯孔布雷斯天文台）
We present the results from four stellar occultations by (486958) Arrokoth, the flyby target of the New Horizons extended mission. Three of the four efforts led to positive detections of the body, and all constrained the presence of rings and other debris, finding none. Twenty-five mobile stations were deployed for 2017 June 3 and augmented by fixed telescopes. There were no positive detections from this effort. The event on 2017 July 10 was observed by SOFIA with one very short chord. Twenty-four deployed stations on 2017 July 17 resulted in five chords that clearly showed a complicated shape…
Among the four known transneptunian dwarf planets, Haumea is an exotic, very elongated, and fast rotating body. In contrast to the other dwarf planets, its size, shape, albedo, and density are not well constrained. Here we report results of a multi-chord stellar occultation, observed on 2017 January 21. Secondary events observed around the main body are consistent with the presence of a ring of opacity 0.5, width 70 km, and radius 2,287$_{-45}^{+75}$ km. The Centaur Chariklo was the first body other than a giant planet to show a ring system and the Centaur Chiron was later found to possess som…
