J/A+A/678/A167ivo://CDS.VizieR/J/A+A/678/A167doi:10.26093/cds/vizier/bc-n6/lbghCDSRommel F.L.Braga-Ribas F.Ortiz J.L.Sicardy B.Santos-Sanz P.,Desmars J.Camargo J.I.B.Vieira-Martins R.Assafin M.Morgado B.E.,Boufleur R.C.Benedetti-Rossi G.Gomes-Junior A.R.,Fernandez-Valenzuela E.Holler B.J.Souami D.Duffard R.Margoti G.,Vara-Lubiano M.Lecacheux J.Plouvier J.L.Morales N.Maury A.,Fabrega J.Ceravolo P.Jehin E.Albanese D.Mariey H.Cikota S.,Ruzdjak D.Cikota A.Szakats R.Baba Aissa D.Gringahcene Z.,Kashuba V.Koshkin N.Zhukov V.Fisek S.Cakir O.Oezer S.,Schnabel C.Schnabel M.Signoret F.Morrone L.Santana-Ros T.,Pereira C.L.Emilio M.Burdanov A.Y.de Wit J.Barkaoui K.Gillon M.,Leto G.Frasca A.Catanzaro G.Zanmar Sanchez R.Tagliaferri U.,Di Sora M.Isopi G.Krugly Y.Slyusarev I.Chiorny V.Mikuz H.,Bacci P.Maestripieri M.Grazia M.D.de la Cueva I.Yuste-Moreno M.,Ciabattari F.Kozhukhov O.M.Serra-Ricart M.Alarcon M.R.Licandro J.,Masi G.Bacci R.Bosch J.M.Behem R.Prost J.-P.Renner S.Conjat M.,Bachini M.Succi G.Stoian L.Juravle A.Carosati D.Gowe B.,Carrillo J.Zheleznyak A.P.Montigiani N.Foster C.R.Mannucci M.,Ruocco N.Cuevas F.Di Marcantonio P.Coretti I.Iafrate G.Baldini V.,Collins M.Pal A.Csak B.Fernandez-Garcia E.Castro-Tirado A.J.,Hudin L.Madiedo J.M.Anghel R.M.Calvo-Fernandez J.F.Valvasori A.,Guido E.Gherase R.M.Kamoun S.Fafet R.Sanchez-Gonzalez M.,Curelaru L.Vintdevara C.D.Danescu C.A.Gout J.-F.Schmitz C.J.,Sota A.Belskaya I.Rodriguez-Marco M.Kilic Y.Frappa E.Klotz A.,Lavayssiere M.Marques Oliveira J.Popescu M.Mammana L.A.,Fernandez-Lajus E.Schmidt M.Hopp U.Komzik R.Pribulla T.Tomko D.,Husarik M.Erece O.Eryilmaz S.Buzzi L.Gaehrken B.Nardiello D.,Hornoch K.Sonbas E.Er H.Burwitz V.Waldemar Sybilski P.Bykowski W.,Mueller T.G.Ogloza W.Goncalves R.Ferreira J.F.Ferreira M.Bento M.,Meister S.Bagiran M.N.Tekes M.Marciniak A.Moravec Z.Delincak P.,Gianni G.Casalnuovo G.B.Boutet M.Sanchez J.Klemt B.Wuensche N.,Burzynski W.Borkowski M.Serrau M.Dangl G.Kloes O.Weber C.,Urbanik M.Rousselot L.Kubanek J.Andre P.Colazo C.Spagnotto J.,Sickafoose A.A.Hueso R.Sanchez-Lavega A.Fisher R.S.Rengstorf A.W.,Perello C.Dascalu M.Altan M.Gazeas K.de Santana T.Sfair R.,Winter O.C.Kalkan S.Canales-Moreno O.Trigo-Rodriguez J.M.Tsamis V.,Tigani K.Sioulas N.Lekkas G.Bertesteanu D.N.Dumitrescu V.,Wilberger A.J.Barnes J.W.Fieber-Beyer S.K.Swaney R.L.Fuentes C.,Mendez R.A.Dumitru B.D.Flynn R.L.Wake D.A.2026-07-01T14:00:55Z2023-10-20T07:46:39ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frsolar-systemasteroidsoccultationobservational-astronomyThe physical characterization of the trans-Neptunian objects is essential for improving our understanding of the solar system's formation and evolution. Stellar occultation is a ground-based technique successfully used to determine some of the TNOs' fundamental physical properties with high precision, such as size and shape. This work aims at constraining the size, shape, and geometric albedo of the dwarf planet candidate (307261) 2002 MS4 through the analysis of nine stellar occultation events. Using multichord detection, we also studied the object's topography by analyzing the obtained limb and the residuals between observed chords and the best-fitted ellipse. We predicted and organized the observational campaigns of nine stellar occultations by 2002 MS4 between 2019 and 2022, resulting in two single-chord events, four double-chord detections, and three events with three to up to sixty-one positive chords. We derived the occultation light curves using differential aperture photometry, from which the star ingress and egress instants were calculated. Using 13 selected chords from the 8 August 2020 event, we determined the global elliptical limb of 2002 MS4. The best-fitted ellipse, combined with the object's rotational information from the literature, constrains the object's size, shape, and albedo. Additionally, we developed a new method to characterize topography features on the object's limb. The global limb has a semi-major axis of 412+/-10km, a semi-minor axis of 385+/-17km, and the position angle of the minor axis is 121{deg}+/-16{deg}. From this instantaneous limb, we obtained 2002 MS4's geometric albedo of p_V_=0.1+/-0.025 using an H_V_=3.63+/-0.05mag and a projected area-equivalent diameter of 796+/-24km. Significant deviations from the fitted ellipse in the northernmost limb are detected from multiple sites highlighting three distinct topographic features: one 11 km depth depression followed by a 25^+4^_-5_km height elevation next to a crater-like depression with an extension of 322+/-39km and 45.1+/-1.5km deep. Our results present an object that is ~138km smaller in diameter than derived from thermal data, possibly indicating the presence of a so-far unknown satellite. However, within the error bars, the geometric albedo in the V-band agrees with the results published in the literature, even with the radiometric-derived albedo. This stellar occultation allowed for a multichord measurement of a large topography in a TNO for the first time.2023A&A...678A.167Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/678/A167CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/678/A167https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/678/A167http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/678/A167https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/678/A167https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/678/A167http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/678/A167GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/678/A167/tableb1Observational circumstances of all observatories that detected the stellar occultation by MS4 on 8 August 2020ObsObservatorymeta.id;instr.obstycharCityNearest citymeta.notecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCountryCountrymeta.notecharLATLatitude of the observatorydegpos.earth.lat;instr.obstydoubleLONLongitude of the observatorydegpos.earth.londoubleAltAltitude of the observatorympos.earth.altitude;instr.obstyfloatTelTelescopemeta.id;instr.telcharAperApertureminstr.fovfloatFiltFiltermeta.id;instr.filtercharTSourceTime source (1)meta.id;instrcharInstInstrumentmeta.id;instrcharExpExposure timestime.expodoublen_Exp[*] Note on Exp (2)meta.notecharl_Cycle[~] Limit lfag on Cyclemeta.code.error;obs.proposal.cyclecharCycle? Cyclesobs.proposal.cycledoublenullablen_Cycle[*] Note on Cyle (2)meta.notecharCorr? Correctionsarith.factordoublenullableObservsObserversobs.observercharJ/A+A/678/A167/tableb2Observational circumstances of all the stations that acquired data of the 8 August 2020 event but did not detect the occultationTSourceTime source (1)meta.id;instrcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObsObservatorymeta.id;instr.obstycharCityNearest citymeta.notecharCountryCountrymeta.notecharLATLatitude of the observatorydegpos.earth.lat;instr.obstydoubleLONLongitude of the observatorydegpos.earth.londoubleAltAltitude of the observatorympos.earth.altitude;instr.obstyfloatAperApertureminstr.fovfloatFiltFiltermeta.id;instr.filtercharInstInstrumentmeta.id;instrcharExpExposure timestime.expodoublen_Exp[*] Note on Exp (2)meta.notecharl_Cycle[~] Limit lfag on Cyclemeta.code.error;obs.proposal.cyclecharCycle? Cyclesobs.proposal.cycledoublenullablen_Cycle[*] Note on Cyle (2)meta.notecharCorr? Correctionsarith.factordoublenullableObservsObserversobs.observercharTelTelescopemeta.id;instr.telcharJ/A+A/678/A167/tableb3Observational circumstances of all the sites that tried to observe the 8 August 2020 event, but experienced bad weather or technical issues and did not acquire any dataTSourceTime sourcemeta.id;instrcharTelTelescopemeta.id;instr.telcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObsObservatorymeta.id;instr.obstycharCityNearest citymeta.notecharCountryCountrymeta.notecharLAT? Latitude of the observatorydegpos.earth.lat;instr.obstydoublenullableLON? Longitude of the observatorydegpos.earth.londoublenullableAlt? Altitude of the observatorympos.earth.altitude;instr.obstyfloatnullableAperApertureminstr.fovfloatInstInstrumentmeta.id;instrcharObservsObserversobs.observercharFiltFiltermeta.id;instr.filtercharJ/A+A/678/A167/tableb4Observational circumstances of all stations that detected 2002 MS4 in a stellar occultation on the other eight eventsTelTelescopemeta.id;instr.telcharAperApertureminstr.fovfloatFiltFiltermeta.id;instr.filtercharTSourceTime sourcemeta.id;instrcharInstInstrumentmeta.id;instrcharExpExposure timestime.expofloatSiteSite/Countrymeta.id;instr.obstycharLATLatitudepos.earth.latLONLongitudepos.earth.lonAltAltitudempos.earth.altitudefloatObservsObserversobs.observercharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateObservation datetime.epoch;obsnullablel_Cycle[~] Limit flag on Cyclemeta.code.error;obs.proposal.cyclecharCycleCyclesobs.proposal.cyclefloatCorr? Correctionsarith.factorfloatnullableJ/A+A/678/A167/tableb5Observational circumstances of all the stations that did not detect 2002 MS4 or experienced bad weather during the other eight stellar occultationsInstInstrument (1)meta.id;instrcharExp? Exposure timestime.expofloatnullableCycle? Cyclesobs.proposal.cyclefloatnullableTSourceTime sourcemeta.id;instrcharObservsObserversobs.observercharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateObservation datetime.epoch;obsnullableSiteSite/Countrymeta.id;instr.obstycharReasonsReasons for no detectionmeta.notecharLAT? Latitudepos.earth.latnullableLON? Longitudepos.earth.lonnullableAlt? Altitudempos.earth.altitudedoublenullableTelTelescopemeta.id;instr.telcharAper? Apertureminstr.fovfloatnullable