Pub Date : 2025-11-07DOI: 10.1038/s41550-025-02704-6
Renaud Merle
Magmatic rocks from the far side of the Moon might not originate from the lunar mantle, but from the mineral cumulates resulting from the crystallization of a magma pond formed by the South Pole–Aitken impact on the far side of the Moon.
{"title":"An impact-related origin for lunar magmatic rocks?","authors":"Renaud Merle","doi":"10.1038/s41550-025-02704-6","DOIUrl":"10.1038/s41550-025-02704-6","url":null,"abstract":"Magmatic rocks from the far side of the Moon might not originate from the lunar mantle, but from the mineral cumulates resulting from the crystallization of a magma pond formed by the South Pole–Aitken impact on the far side of the Moon.","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":"9 11","pages":"1604-1606"},"PeriodicalIF":14.3,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145455688","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}
Pub Date : 2025-11-05DOI: 10.1038/s41550-025-02695-4
Akhil Uniyal, Indu K. Dihingia, Yosuke Mizuno, Luciano Rezzolla
The horizon-scale images of supermassive black holes (BHs) by the Event Horizon Telescope Collaboration have provided new opportunities to test general relativity and other theories of gravity. In view of future projects, such as the next-generation Event Horizon Telescope and the Black Hole Explorer, which have the potential to enhance our ability to probe extreme gravity, it is natural to ask how much two BH images can differ. To address this question and assess the ability of these projects to test theories of gravity with BH shadows, we use general-relativistic magnetohydrodynamic and radiative-transfer simulations to investigate the images of a wide class of accreting BHs deviating from the Kerr solution. By measuring the mismatch between images of different BHs, we show that future missions will be able to distinguish a large class of BH solutions from the Kerr solution when the mismatch in the images exceeds values between 2% and 5% depending on the image-comparison metric considered. These results indicate that future horizon-scale imaging with percent-level image fidelity can place meaningful observational constraints on deviations from the Kerr metric and thereby test strong-field predictions of general relativity. General-relativistic magnetohydrodynamic simulations coupled with general-relativistic radiation transfer of a wide class of black hole spacetimes forecast the ability of future VLBI projects to distinguish between black hole images.
{"title":"The future ability to test theories of gravity with black-hole shadows","authors":"Akhil Uniyal, Indu K. Dihingia, Yosuke Mizuno, Luciano Rezzolla","doi":"10.1038/s41550-025-02695-4","DOIUrl":"10.1038/s41550-025-02695-4","url":null,"abstract":"The horizon-scale images of supermassive black holes (BHs) by the Event Horizon Telescope Collaboration have provided new opportunities to test general relativity and other theories of gravity. In view of future projects, such as the next-generation Event Horizon Telescope and the Black Hole Explorer, which have the potential to enhance our ability to probe extreme gravity, it is natural to ask how much two BH images can differ. To address this question and assess the ability of these projects to test theories of gravity with BH shadows, we use general-relativistic magnetohydrodynamic and radiative-transfer simulations to investigate the images of a wide class of accreting BHs deviating from the Kerr solution. By measuring the mismatch between images of different BHs, we show that future missions will be able to distinguish a large class of BH solutions from the Kerr solution when the mismatch in the images exceeds values between 2% and 5% depending on the image-comparison metric considered. These results indicate that future horizon-scale imaging with percent-level image fidelity can place meaningful observational constraints on deviations from the Kerr metric and thereby test strong-field predictions of general relativity. General-relativistic magnetohydrodynamic simulations coupled with general-relativistic radiation transfer of a wide class of black hole spacetimes forecast the ability of future VLBI projects to distinguish between black hole images.","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":"10 1","pages":"165-172"},"PeriodicalIF":14.3,"publicationDate":"2025-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145440880","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}
Pub Date : 2025-11-04DOI: 10.1038/s41550-025-02699-0
Matthew J. Graham, Barry McKernan, K. E. Saavik Ford, Daniel Stern, Matteo Cantiello, Andrew J. Drake, Yuanze Ding, Mansi Kasliwal, Mike Koss, Raffaella Margutti, Sam Rose, Jean Somalwar, Phil Wiseman, S. G. Djorgovski, Patrik M. Veres, Eric C. Bellm, Tracy X. Chen, Steven L. Groom, Shrinivas R. Kulkarni, Ashish Mahabal
Since their discovery more than 60 years ago, accreting supermassive black holes in active galactic nuclei (AGN) have been recognized as highly variable sources, requiring an extremely compact, dynamic environment. Their variability is related to several phenomena, including changing accretion rates, temperature changes, foreground absorbers and structural changes to the accretion disk. Spurred by a new generation of time-domain surveys, the extremes of black hole variability are now being probed. Here we describe the discovery of an extreme flare by the AGN J224554.84+374326.5, which brightened by more than a factor of 40 in 2018. The source has slowly faded since then. The total emitted ultraviolet and optical energy to date is ~1054 erg, which represents the complete conversion of approximately one solar mass into electromagnetic radiation. This flare is 30 times more powerful than the previous most powerful AGN transient. Very few physical events in the Universe can liberate this much electromagnetic energy. We discuss potential mechanisms, including the tidal disruption of a high-mass star (>30 M⊙), gravitational lensing of an AGN flare or supernova, or a supermassive (pair-instability) supernova in the accretion disk of an AGN. We favour the tidal disruption of a massive star in a prograde orbit in an AGN disk. An extreme flare has been seen from a supermassive black hole at redshift z = 2.6. First detected in 2018, it is 30 times brighter than similar events. The most likely cause is the shredding of a star of 30 solar masses or more.
{"title":"An extremely luminous flare recorded from a supermassive black hole","authors":"Matthew J. Graham, Barry McKernan, K. E. Saavik Ford, Daniel Stern, Matteo Cantiello, Andrew J. Drake, Yuanze Ding, Mansi Kasliwal, Mike Koss, Raffaella Margutti, Sam Rose, Jean Somalwar, Phil Wiseman, S. G. Djorgovski, Patrik M. Veres, Eric C. Bellm, Tracy X. Chen, Steven L. Groom, Shrinivas R. Kulkarni, Ashish Mahabal","doi":"10.1038/s41550-025-02699-0","DOIUrl":"10.1038/s41550-025-02699-0","url":null,"abstract":"Since their discovery more than 60 years ago, accreting supermassive black holes in active galactic nuclei (AGN) have been recognized as highly variable sources, requiring an extremely compact, dynamic environment. Their variability is related to several phenomena, including changing accretion rates, temperature changes, foreground absorbers and structural changes to the accretion disk. Spurred by a new generation of time-domain surveys, the extremes of black hole variability are now being probed. Here we describe the discovery of an extreme flare by the AGN J224554.84+374326.5, which brightened by more than a factor of 40 in 2018. The source has slowly faded since then. The total emitted ultraviolet and optical energy to date is ~1054 erg, which represents the complete conversion of approximately one solar mass into electromagnetic radiation. This flare is 30 times more powerful than the previous most powerful AGN transient. Very few physical events in the Universe can liberate this much electromagnetic energy. We discuss potential mechanisms, including the tidal disruption of a high-mass star (>30 M⊙), gravitational lensing of an AGN flare or supernova, or a supermassive (pair-instability) supernova in the accretion disk of an AGN. We favour the tidal disruption of a massive star in a prograde orbit in an AGN disk. An extreme flare has been seen from a supermassive black hole at redshift z = 2.6. First detected in 2018, it is 30 times brighter than similar events. The most likely cause is the shredding of a star of 30 solar masses or more.","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":"10 1","pages":"154-164"},"PeriodicalIF":14.3,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145434657","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}
Pub Date : 2025-10-31DOI: 10.1038/s41550-025-02693-6
Di-Chang Chen, Ji-Wei Xie, Ji-Lin Zhou, Fei Dai, Bo Ma, Songhu Wang, Chao Liu
The discovery of hot Jupiters has challenged classical planet formation theories. Although various formation mechanisms have been proposed, their relative contributions remain unclear. Furthermore, hot Jupiters offer a unique opportunity to test tidal theory and measure the fundamental tidal quality factor $${Q}_{* }^{{prime} }$$ , which is yet to be well constrained. Here we use a sample of 123 hot Jupiters around single Sun-like stars and find that the slope of the decline in frequency with age abruptly changes at around 2 Gyr, indicative of the presence of two populations of hot Jupiters that formed at different timescales. We use a tidal evolution model to infer a value of $$log {Q}_{* }^{{prime} } approx5.{7}_{-0.3}^{+0.4}$$ for Sun-like stars, which reproduces well the number of observed hot Jupiters undergoing orbital decay. We also constrain the relative importance of the two formation channels: most hot Jupiters form within a few hundred million years through ‘early’ models (for example, in situ formation, disk migration, planet–planet scattering and Kozai–Lidov interactions), whereas a substantial portion ( $$3{8}_{-14}^{+16} %$$ ) forms late with a timescale of several billion years, mainly thorough secular chaotic migration. This result is supported by the observed obliquity distribution of ‘late-arriving’ hot Jupiters. Our findings provide a unified framework that reconciles hot Jupiter demographics and long-term evolution with multichannel formation. This study reveals a broken age–frequency relation of hot Jupiters, which simultaneously constrains the tidal factor of host stars and indicates different timescales in hot Jupiter formation, with ~40% forming late on billion-year timescales through secular chaos.
热木星的发现挑战了经典的行星形成理论。虽然提出了各种形成机制，但它们的相对贡献尚不清楚。此外，热木星提供了一个独特的机会来测试潮汐理论和测量基本的潮汐质量因子$${Q}_{* }^{{prime} }$$，这还没有得到很好的限制。在这里，我们使用了123颗热木星围绕单一类太阳恒星的样本，发现频率随年龄下降的斜率在2 Gyr左右突然改变，这表明在不同时间尺度上形成的两个热木星种群的存在。我们使用潮汐演化模型来推断类太阳恒星的值$$log {Q}_{* }^{{prime} } approx5.{7}_{-0.3}^{+0.4}$$，它很好地再现了观测到的经历轨道衰变的热木星的数量。我们还限制了两种形成通道的相对重要性：大多数热木星通过“早期”模型（例如，原位形成，磁盘迁移，行星-行星散射和Kozai-Lidov相互作用）在几亿年内形成，而相当一部分（$$3{8}_{-14}^{+16} %$$）形成较晚，时间尺度为数十亿年，主要是长期混沌迁移。这一结果得到了观测到的“晚到”热木星的倾角分布的支持。我们的发现提供了一个统一的框架，调和热木星的人口统计和长期演变与多通道形成。这项研究揭示了热木星的年龄-频率关系的破碎，这同时限制了主恒星的潮汐因子，并表明热木星形成的不同时间尺度，其中40% forming late on billion-year timescales through secular chaos.
{"title":"The origin and tidal evolution of hot Jupiters constrained by a broken age–frequency relation","authors":"Di-Chang Chen, Ji-Wei Xie, Ji-Lin Zhou, Fei Dai, Bo Ma, Songhu Wang, Chao Liu","doi":"10.1038/s41550-025-02693-6","DOIUrl":"10.1038/s41550-025-02693-6","url":null,"abstract":"The discovery of hot Jupiters has challenged classical planet formation theories. Although various formation mechanisms have been proposed, their relative contributions remain unclear. Furthermore, hot Jupiters offer a unique opportunity to test tidal theory and measure the fundamental tidal quality factor $${Q}_{* }^{{prime} }$$ , which is yet to be well constrained. Here we use a sample of 123 hot Jupiters around single Sun-like stars and find that the slope of the decline in frequency with age abruptly changes at around 2 Gyr, indicative of the presence of two populations of hot Jupiters that formed at different timescales. We use a tidal evolution model to infer a value of $$log {Q}_{* }^{{prime} } approx5.{7}_{-0.3}^{+0.4}$$ for Sun-like stars, which reproduces well the number of observed hot Jupiters undergoing orbital decay. We also constrain the relative importance of the two formation channels: most hot Jupiters form within a few hundred million years through ‘early’ models (for example, in situ formation, disk migration, planet–planet scattering and Kozai–Lidov interactions), whereas a substantial portion ( $$3{8}_{-14}^{+16} %$$ ) forms late with a timescale of several billion years, mainly thorough secular chaotic migration. This result is supported by the observed obliquity distribution of ‘late-arriving’ hot Jupiters. Our findings provide a unified framework that reconciles hot Jupiter demographics and long-term evolution with multichannel formation. This study reveals a broken age–frequency relation of hot Jupiters, which simultaneously constrains the tidal factor of host stars and indicates different timescales in hot Jupiter formation, with ~40% forming late on billion-year timescales through secular chaos.","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":"10 1","pages":"92-104"},"PeriodicalIF":14.3,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145404843","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}
Pub Date : 2025-10-28DOI: 10.1038/s41550-025-02692-7
Bin Yue
A new study brings a fresh chance to detect small-scale primordial fluctuations and the nature of dark matter in early stages of the Universe, using simple global 21 cm signal experiments rather than expensive interferometer arrays.
{"title":"Traces of small dark structures in the global 21 cm signal","authors":"Bin Yue","doi":"10.1038/s41550-025-02692-7","DOIUrl":"10.1038/s41550-025-02692-7","url":null,"abstract":"A new study brings a fresh chance to detect small-scale primordial fluctuations and the nature of dark matter in early stages of the Universe, using simple global 21 cm signal experiments rather than expensive interferometer arrays.","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":"9 11","pages":"1607-1608"},"PeriodicalIF":14.3,"publicationDate":"2025-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145382459","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}
Pub Date : 2025-10-28DOI: 10.1038/s41550-025-02666-9
Ryan C. Challener, Megan Weiner Mansfield, Patricio E. Cubillos, Anjali A. A. Piette, Louis-Philippe Coulombe, Hayley Beltz, Jasmina Blecic, Emily Rauscher, Jacob L. Bean, Björn Benneke, Eliza M.-R. Kempton, Joseph Harrington, Thaddeus D. Komacek, Vivien Parmentier, S. L. Casewell, Nicolas Iro, Luigi Mancini, Matthew C. Nixon, Michael Radica, Maria E. Steinrueck, Luis Welbanks, Natalie M. Batalha, Claudio Caceres, Ian J. M. Crossfield, Nicolas Crouzet, Jean-Michel Désert, Karan Molaverdikhani, Nikolay K. Nikolov, Enric Palle, Benjamin V. Rackham, Everett Schlawin, David K. Sing, Kevin B. Stevenson, Xianyu Tan, Jake D. Turner, Xi Zhang
Highly irradiated giant exoplanets known ‘ultrahot Jupiters’ are anticipated to exhibit large variations of atmospheric temperature and chemistry as a function of longitude, latitude and altitude. Previous observations have hinted at these variations, but the existing data have been fundamentally restricted to probing hemisphere-integrated spectra, thereby providing only coarse information on atmospheric gradients. Here we present a spectroscopic eclipse map of an extrasolar planet, resolving the atmosphere in multiple dimensions simultaneously. We analyse a secondary eclipse of the ultrahot Jupiter WASP-18b observed with the Near Infrared Imager and Slitless Spectrograph instrument on the JWST. The mapping reveals weaker longitudinal temperature gradients than were predicted by theoretical models, indicating the importance of hydrogen dissociation and/or nightside clouds in shaping global thermal emission. In addition, we identify two thermally distinct regions of the planet’s atmosphere: a ‘hotspot’ surrounding the substellar point and a ‘ring’ near the dayside limbs. The hotspot region shows a strongly inverted thermal structure due to the presence of optical absorbers and a water abundance marginally lower than the hemispheric average, in accordance with theoretical predictions. The ring region shows colder temperatures and poorly constrained chemical abundances. Similar future analyses will reveal the three-dimensional thermal, chemical and dynamical properties of a broad range of exoplanet atmospheres. JWST data show that the exoplanet WASP-18b has thermally distinct regions of its dayside. The authors mapped the sizes of these regions, measured their temperatures and potentially identify water destruction in the hottest region.
{"title":"Horizontal and vertical exoplanet thermal structure from a JWST spectroscopic eclipse map","authors":"Ryan C. Challener, Megan Weiner Mansfield, Patricio E. Cubillos, Anjali A. A. Piette, Louis-Philippe Coulombe, Hayley Beltz, Jasmina Blecic, Emily Rauscher, Jacob L. Bean, Björn Benneke, Eliza M.-R. Kempton, Joseph Harrington, Thaddeus D. Komacek, Vivien Parmentier, S. L. Casewell, Nicolas Iro, Luigi Mancini, Matthew C. Nixon, Michael Radica, Maria E. Steinrueck, Luis Welbanks, Natalie M. Batalha, Claudio Caceres, Ian J. M. Crossfield, Nicolas Crouzet, Jean-Michel Désert, Karan Molaverdikhani, Nikolay K. Nikolov, Enric Palle, Benjamin V. Rackham, Everett Schlawin, David K. Sing, Kevin B. Stevenson, Xianyu Tan, Jake D. Turner, Xi Zhang","doi":"10.1038/s41550-025-02666-9","DOIUrl":"10.1038/s41550-025-02666-9","url":null,"abstract":"Highly irradiated giant exoplanets known ‘ultrahot Jupiters’ are anticipated to exhibit large variations of atmospheric temperature and chemistry as a function of longitude, latitude and altitude. Previous observations have hinted at these variations, but the existing data have been fundamentally restricted to probing hemisphere-integrated spectra, thereby providing only coarse information on atmospheric gradients. Here we present a spectroscopic eclipse map of an extrasolar planet, resolving the atmosphere in multiple dimensions simultaneously. We analyse a secondary eclipse of the ultrahot Jupiter WASP-18b observed with the Near Infrared Imager and Slitless Spectrograph instrument on the JWST. The mapping reveals weaker longitudinal temperature gradients than were predicted by theoretical models, indicating the importance of hydrogen dissociation and/or nightside clouds in shaping global thermal emission. In addition, we identify two thermally distinct regions of the planet’s atmosphere: a ‘hotspot’ surrounding the substellar point and a ‘ring’ near the dayside limbs. The hotspot region shows a strongly inverted thermal structure due to the presence of optical absorbers and a water abundance marginally lower than the hemispheric average, in accordance with theoretical predictions. The ring region shows colder temperatures and poorly constrained chemical abundances. Similar future analyses will reveal the three-dimensional thermal, chemical and dynamical properties of a broad range of exoplanet atmospheres. JWST data show that the exoplanet WASP-18b has thermally distinct regions of its dayside. The authors mapped the sizes of these regions, measured their temperatures and potentially identify water destruction in the hottest region.","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":"9 12","pages":"1821-1832"},"PeriodicalIF":14.3,"publicationDate":"2025-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.comhttps://www.nature.com/articles/s41550-025-02666-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145382418","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}
Pub Date : 2025-10-27DOI: 10.1038/s41550-025-02691-8
Kosuke Namekata, Kevin France, Jongchul Chae, Vladimir S. Airapetian, Adam Kowalski, Yuta Notsu, Peter R. Young, Satoshi Honda, Soosang Kang, Juhyung Kang, Kyeore Lee, Hiroyuki Maehara, Kyoung-Sun Lee, Cole Tamburri, Tomohito Ohshima, Masaki Takayama, Kazunari Shibata
Coronal mass ejections (CMEs) on the early Sun may have profoundly influenced the planetary atmospheres of early Solar System planets. Flaring young solar analogues serve as excellent proxies for probing the plasma environment of the young Sun, yet their CMEs remain poorly understood. Here we report the detection of multi-wavelength Doppler shifts of the far-ultraviolet and optical lines during a flare on the young solar analogue EK Draconis. During and before a Carrington-class (~1032 erg) flare, warm far-ultraviolet lines (~105 K) exhibited blueshifted emission at 300–550 km s−1, indicative of a warm eruption. Then, 10 min later, the Hα line showed slow (70 km s−1), long-lasting (≳2 h) blueshifted absorptions, indicating a cool (~104 K) filament eruption. This provides evidence of the multi-temperature and multi-component nature of a stellar CME. If Carrington-class flares or CMEs occurred frequently on the young Sun, they may have cumulatively impacted the early Earth’s magnetosphere and atmosphere. Observations of multi-temperature stellar eruptions from EK Draconis reveal a solar-like yet complex view of stellar coronal mass ejections. Such frequent, powerful events on the young Sun may have shaped Earth’s early atmosphere.
早期太阳的日冕物质抛射（cme）可能对早期太阳系行星的行星大气产生了深远的影响。燃烧的年轻太阳类似物是探测年轻太阳等离子体环境的绝佳代理，但它们的日冕物质抛射仍然知之甚少。在这里，我们报告了在年轻的太阳类似物EK dragonis的耀斑上探测到远紫外和光学线的多波长多普勒频移。在卡灵顿级（~10 32 erg）耀斑期间和之前，温暖的远紫外线（~10 5 K）在300-550 km s - 1范围内表现出蓝移发射，表明温暖的喷发。然后，10分钟后，h α线显示出缓慢（70 km s−1），持久（约2 h）的蓝移吸收，表明冷（约10 4 K）的长丝喷发。这为恒星CME的多温度和多成分性质提供了证据。如果卡灵顿级耀斑或日冕物质抛射经常发生在年轻的太阳上，它们可能累积影响了早期地球的磁层和大气。
{"title":"Discovery of multi-temperature coronal mass ejection signatures from a young solar analogue","authors":"Kosuke Namekata, Kevin France, Jongchul Chae, Vladimir S. Airapetian, Adam Kowalski, Yuta Notsu, Peter R. Young, Satoshi Honda, Soosang Kang, Juhyung Kang, Kyeore Lee, Hiroyuki Maehara, Kyoung-Sun Lee, Cole Tamburri, Tomohito Ohshima, Masaki Takayama, Kazunari Shibata","doi":"10.1038/s41550-025-02691-8","DOIUrl":"10.1038/s41550-025-02691-8","url":null,"abstract":"Coronal mass ejections (CMEs) on the early Sun may have profoundly influenced the planetary atmospheres of early Solar System planets. Flaring young solar analogues serve as excellent proxies for probing the plasma environment of the young Sun, yet their CMEs remain poorly understood. Here we report the detection of multi-wavelength Doppler shifts of the far-ultraviolet and optical lines during a flare on the young solar analogue EK Draconis. During and before a Carrington-class (~1032 erg) flare, warm far-ultraviolet lines (~105 K) exhibited blueshifted emission at 300–550 km s−1, indicative of a warm eruption. Then, 10 min later, the Hα line showed slow (70 km s−1), long-lasting (≳2 h) blueshifted absorptions, indicating a cool (~104 K) filament eruption. This provides evidence of the multi-temperature and multi-component nature of a stellar CME. If Carrington-class flares or CMEs occurred frequently on the young Sun, they may have cumulatively impacted the early Earth’s magnetosphere and atmosphere. Observations of multi-temperature stellar eruptions from EK Draconis reveal a solar-like yet complex view of stellar coronal mass ejections. Such frequent, powerful events on the young Sun may have shaped Earth’s early atmosphere.","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":"10 1","pages":"64-75"},"PeriodicalIF":14.3,"publicationDate":"2025-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.comhttps://www.nature.com/articles/s41550-025-02691-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145382416","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}
Pub Date : 2025-10-24DOI: 10.1038/s41550-025-02690-9
R. J. Morton, Y. Gao, E. Tajfirouze, H. Tian, T. Van Doorsselaere, T. A. Schad
The corona is the outermost layer of the Sun’s atmosphere. Its plasma is accelerated and flows out into interplanetary space as a heated, supersonic wind. The details of energy and momentum transfer to the plasma remain debated. Alfvén waves are a favoured mechanism, and in a plasma composed of inhomogeneous flux tubes, the only pure Alfvén mode is torsional in nature. Large-scale modes have been observed sporadically, but a prevalent, small-scale counterpart in the corona has yet to be established. The Daniel K. Inouye Solar Telescope has begun to provide unprecedented views of the Sun, with the Cryo-NIRSP instrument delivering coronal observations with a high spatial and spectral resolution. Here the data reveal that the quiescent corona supports torsional Alfvén waves, which continuously twist the magnetic field lines back and forth. The measured wave amplitudes are small but are probably underestimated due to the line-of-sight integration. The results indicate that the waves may carry a substantial fraction of the energy required to power the quiet Sun and solar wind. This study uses observations from the DKI Solar Telescope to reveal that the Sun’s corona hosts small-scale torsional Alfvén waves. These twisting motions likely carry enough energy to help heat the Sun’s atmosphere and drive the solar wind.
日冕是太阳大气层的最外层。它的等离子体被加速，以加热的超音速风的形式流入行星际空间。能量和动量向等离子体转移的细节仍存在争议。alfvsamn波是一种有利的机制，在由非均匀磁通管组成的等离子体中，唯一纯alfvsamn模式本质上是扭转的。大尺度模式已被零星地观察到，但在日冕中普遍存在的小尺度模式尚未建立。Daniel K. Inouye太阳望远镜已经开始提供前所未有的太阳视图，Cryo-NIRSP仪器提供了高空间和光谱分辨率的日冕观测。这里的数据显示，静止的日冕支持扭转的阿尔夫萨芬波，它不断地来回扭曲磁场线。测量到的波幅很小，但由于视距积分可能被低估了。结果表明，这些波浪可能携带了相当一部分能量，为安静的太阳和太阳风提供能量。
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Pub Date : 2025-10-21DOI: 10.1038/s41550-025-02674-9
By generating natural-language explanations alongside accurate classifications, large language models offer a new way to filter astronomical alerts — bridging the gap between fast automation and human understanding.
{"title":"Human-readable classification of astronomical images using large language models","authors":"","doi":"10.1038/s41550-025-02674-9","DOIUrl":"10.1038/s41550-025-02674-9","url":null,"abstract":"By generating natural-language explanations alongside accurate classifications, large language models offer a new way to filter astronomical alerts — bridging the gap between fast automation and human understanding.","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":"9 12","pages":"1762-1763"},"PeriodicalIF":14.3,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145382419","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}
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