Nature Astronomy最新文献_第8页

Dynamic electron radiation belt at Mercury controlled by solar wind driving 由太阳风驱动的水星动态电子辐射带

IF 15.2 1区物理与天体物理

Nature Astronomy Pub Date : 2026-07-27 DOI: 10.1038/s41550-026-02925-3

Jiutong Zhao (, ), Ryan M. Dewey, Weijie Sun (, ), James A. Slavin, Paul S. Szabo, Lucas Liuzzo, Nicolas André, Mathias Rojo

{"title":"Dynamic electron radiation belt at Mercury controlled by solar wind driving","authors":"Jiutong Zhao \u0000 (, ), Ryan M. Dewey, Weijie Sun \u0000 (, ), James A. Slavin, Paul S. Szabo, Lucas Liuzzo, Nicolas André, Mathias Rojo","doi":"10.1038/s41550-026-02925-3","DOIUrl":"10.1038/s41550-026-02925-3","url":null,"abstract":"Electron radiation belts, reservoirs of stably trapped energetic electrons hazardous to space technology, are a prevalent feature of most magnetized planetary environments. However, their existence in the compact magnetosphere of Mercury has been a subject of debate for decades. The presence of energetic electrons was first identified by Mariner 10’s observations in the 1970s but was subsequently questioned by MESSENGER’s limited energetic particle measurements 40 years later. Here we integrate MESSENGER’s more sensitive indirect energetic electron measurements with new analysis techniques, particle simulations and theory to discover a structured radiation belt with a variable morphology subject to solar wind activity. This radiation belt can persist for several Earth days and, thus, seems to be quasi-permanent under weak solar wind forcing. However, it becomes unstable under strong driving as electron drift orbits bifurcate about the magnetic equator within the dayside magnetosphere and particles are rapidly lost. Our results establish that even compact magnetospheres can host radiation belts and, furthermore, that Mercury is a natural laboratory for radiation-belt physics usually inaccessible at Earth: one of an extreme, rapidly driven state. Mercury is found to host a radiation belt under weak solar wind driving that becomes unstable during strong forcing, providing insights into energetic particle dynamics in an extreme planetary environment.","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":"10 10","pages":"1489-1499"},"PeriodicalIF":15.2,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.comhttps://www.nature.com/articles/s41550-026-02925-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148612607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Kilometre-scale Jovian moon characterized for a potential JUICE flyby 千米尺度的木星卫星，具有潜在的JUICE飞掠特征

IF 14.1 1区物理与天体物理

Nature Astronomy Pub Date : 2026-07-24 DOI: 10.1038/s41550-026-02929-z

Juan Luis Rizos, Jose María Gómez-Limón, Yucel Kilic, Altair R. Gomes-Júnior, Jose Luis Ortiz, Nicolas Morales, Álvaro Álvarez-Candal, Pasquale Palumbo, Luisa M. Lara, Simon Porter, Benjamin Proudfoot, Evelyn Christiny M. Prais, Jean Marc Christille, Stefano Sartor, Antonio Cabrera, Stefan Geier, Alessia Spolon, Alice Lucchetti, Andrea Soffiantini, Anne Verbiscer, Armin Behrend, Elena Mazzotta Epifani, Jean-Louis Dumont, Luca Zampieri, Mike Skrutskie, Maurizio Pajola, Michel Boutet, Michele Fiori, Raoul Behrend, Stefano Sposetti, Vadim Nikitin, Fabien Cavaille, Jocelyn Sérot, Laurent Miralabe, Marc Buie, Mehmed Naim Bagiran, Metin Altan, Mohammad Niaei, Noël Robichon, Orhan Erece, Pierre-Louis Phan, Raphael Lallemand, Süleyman Fişek, Valentin Etienne, Valery Lainey, Yavuz Güney, Yusuf Avcioglu, Francois Poulet, Paul Hartogh, Oliver Witasse, Pablo Santos-Sanz

{"title":"Kilometre-scale Jovian moon characterized for a potential JUICE flyby","authors":"Juan Luis Rizos, Jose María Gómez-Limón, Yucel Kilic, Altair R. Gomes-Júnior, Jose Luis Ortiz, Nicolas Morales, Álvaro Álvarez-Candal, Pasquale Palumbo, Luisa M. Lara, Simon Porter, Benjamin Proudfoot, Evelyn Christiny M. Prais, Jean Marc Christille, Stefano Sartor, Antonio Cabrera, Stefan Geier, Alessia Spolon, Alice Lucchetti, Andrea Soffiantini, Anne Verbiscer, Armin Behrend, Elena Mazzotta Epifani, Jean-Louis Dumont, Luca Zampieri, Mike Skrutskie, Maurizio Pajola, Michel Boutet, Michele Fiori, Raoul Behrend, Stefano Sposetti, Vadim Nikitin, Fabien Cavaille, Jocelyn Sérot, Laurent Miralabe, Marc Buie, Mehmed Naim Bagiran, Metin Altan, Mohammad Niaei, Noël Robichon, Orhan Erece, Pierre-Louis Phan, Raphael Lallemand, Süleyman Fişek, Valentin Etienne, Valery Lainey, Yavuz Güney, Yusuf Avcioglu, Francois Poulet, Paul Hartogh, Oliver Witasse, Pablo Santos-Sanz","doi":"10.1038/s41550-026-02929-z","DOIUrl":"https://doi.org/10.1038/s41550-026-02929-z","url":null,"abstract":"Jupiter’s irregular satellites are thought to be relics of early Solar System planetesimals. However, their small sizes, large distances from Earth and close angular proximity to Jupiter, make them difficult to characterize remotely. Here we report multi-instrument observations of the kilometre-sized Kallichore, the only irregular moon of Jupiter amenable to a close flyby of the European Space Agency’s Jupiter Icy Moons Explorer, with its astrometric and physical properties still poorly constrained. We used Hubble photometry and astrometry, followed by a ground-based multi-site stellar occultation campaign and by astrometric and photometric observations from the 10.4-m Gran Telescopio de Canarias. We could reduce Kallichore’s orbital uncertainty by up to ~80% and determine its shape: an elongated object with a minimum semi-axis ratio a/b = 1.53 ± 0.10, an area-equivalent diameter of (3.{8}_{-0.3}^{+2.3}) km and a dark surface with geometric albedo (3.7_{-2.2}^{+0.7} %). No close companions were detected. These new constraints provide a viable pathway towards a Jupiter Icy Moons Explorer flyby once the spacecraft arrives at the Jupiter system in 2031.","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":"263 1","pages":""},"PeriodicalIF":14.1,"publicationDate":"2026-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148587307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Limited direct fluid exchange between the deep subsurface ocean and the shallow subsurface environment of Europa 木卫二深层地下海洋与浅层地下环境之间的直接流体交换有限

IF 14.1 1区物理与天体物理

Nature Astronomy Pub Date : 2026-07-23 DOI: 10.1038/s41550-026-02918-2

Lujendra Ojha, Ankit Barik, Jacob Buffo

{"title":"Limited direct fluid exchange between the deep subsurface ocean and the shallow subsurface environment of Europa","authors":"Lujendra Ojha, Ankit Barik, Jacob Buffo","doi":"10.1038/s41550-026-02918-2","DOIUrl":"https://doi.org/10.1038/s41550-026-02918-2","url":null,"abstract":"Numerous icy moons, including Europa, possess subsurface oceans beneath their icy exteriors. Liquid water from Europa’s deep ocean has been proposed to rise through dykes and form shallow sills. Such reservoirs could create transient habitable environments and may be directly linked to the formation of various surface features on Europa. However, whether dykes can transport enough water from Europa’s deep ocean to form these shallow reservoirs remains poorly constrained. Here we couple high-resolution laminar and turbulent fluid–thermal simulations to test this mechanism. We first show that, even when we completely neglect convective heat losses, thus providing an upper-bound estimate, the volume of water capable of ascending through dykes before freezing is insufficient to account for the hypothesized surface features. We then show that turbulence notably strengthens this limitation by enhancing heat loss, driving rapid supercooling, promoting frazil ice formation and accelerating dyke clogging. Our results suggest that direct fluid exchange between Europa’s deep ocean and shallow subsurface is minimal and that in situ melting may be the primary source of any shallow liquid water, if present. Notably, this also implies that shallow liquid reservoirs, if encountered by future missions, may not truly reflect the geochemical signature of the underlying ocean.","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":"19 1","pages":""},"PeriodicalIF":14.1,"publicationDate":"2026-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148587322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Cometary tail detected on a near-Earth object based on nongravitational perturbations 基于非引力扰动在近地天体上探测到的彗星尾巴

IF 15.2 1区物理与天体物理

Nature Astronomy Pub Date : 2026-07-21 DOI: 10.1038/s41550-026-02912-8

引用次数: 0

GRaviCon2026 GRaviCon2026

IF 15.2 1区物理与天体物理

Nature Astronomy Pub Date : 2026-07-21 DOI: 10.1038/s41550-026-02924-4

Ilaria Caporali, Gabriele Astorino, Matteo Baratti, Elisa Bigongiari, Giulia Capurri, Luca Muccillo, Dario Rossi, Lorenzo Valbusa Dall’Armi

引用次数: 0

Sugar detected in interstellar space 在星际空间检测到糖

IF 15.2 1区物理与天体物理