Pub Date : 2024-06-21DOI: 10.1038/s41550-024-02305-9
Henrik Melin, J. O’Donoghue, L. Moore, T. S. Stallard, L. N. Fletcher, M. T. Roman, J. Harkett, O. R. T. King, E. M. Thomas, R. Wang, P. I. Tiranti, K. L. Knowles, I. de Pater, T. Fouchet, P. H. Fry, M. H. Wong, B. J. Holler, R. Hueso, M. K. James, G. S. Orton, A. Mura, A. Sánchez-Lavega, E. Lellouch, K. de Kleer, M. R. Showalter
Jupiter’s upper atmosphere is composed of a neutral thermosphere and charged ionosphere. In the latter, the dominant molecular ion H3+ emits in the near-infrared, allowing for the remote exploration of the physical properties of the upper atmosphere. However, the Jovian low-latitude ionosphere remains largely unexplored because H3+ emissions from this region are faint and spectrally entangled with bright neutral species, such as CH4. Here, we present James Webb Space Telescope H3+ observations of Jupiter’s low-latitude ionosphere in the region of the Great Red Spot, showing unexpected small-scale intensity features such as arcs, bands and spots. Our observations may imply that the low-latitude ionosphere of Jupiter is strongly coupled to the lower atmosphere via gravity waves that superimpose to produce this complex and intricate morphology. JWST has revealed unexpected and complex emissions structures in the upper atmosphere of Jupiter, above the Great Red Spot. These features suggest that different atmospheric layers are strongly coupled by gravity waves.
{"title":"Ionospheric irregularities at Jupiter observed by JWST","authors":"Henrik Melin, J. O’Donoghue, L. Moore, T. S. Stallard, L. N. Fletcher, M. T. Roman, J. Harkett, O. R. T. King, E. M. Thomas, R. Wang, P. I. Tiranti, K. L. Knowles, I. de Pater, T. Fouchet, P. H. Fry, M. H. Wong, B. J. Holler, R. Hueso, M. K. James, G. S. Orton, A. Mura, A. Sánchez-Lavega, E. Lellouch, K. de Kleer, M. R. Showalter","doi":"10.1038/s41550-024-02305-9","DOIUrl":"10.1038/s41550-024-02305-9","url":null,"abstract":"Jupiter’s upper atmosphere is composed of a neutral thermosphere and charged ionosphere. In the latter, the dominant molecular ion H3+ emits in the near-infrared, allowing for the remote exploration of the physical properties of the upper atmosphere. However, the Jovian low-latitude ionosphere remains largely unexplored because H3+ emissions from this region are faint and spectrally entangled with bright neutral species, such as CH4. Here, we present James Webb Space Telescope H3+ observations of Jupiter’s low-latitude ionosphere in the region of the Great Red Spot, showing unexpected small-scale intensity features such as arcs, bands and spots. Our observations may imply that the low-latitude ionosphere of Jupiter is strongly coupled to the lower atmosphere via gravity waves that superimpose to produce this complex and intricate morphology. JWST has revealed unexpected and complex emissions structures in the upper atmosphere of Jupiter, above the Great Red Spot. These features suggest that different atmospheric layers are strongly coupled by gravity waves.","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41550-024-02305-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141436116","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 : 2024-06-21DOI: 10.1038/s41550-024-02294-9
Alexandra Veledina, Fabio Muleri, Juri Poutanen, Jakub Podgorný, Michal Dovčiak, Fiamma Capitanio, Eugene Churazov, Alessandra De Rosa, Alessandro Di Marco, Sofia V. Forsblom, Philip Kaaret, Henric Krawczynski, Fabio La Monaca, Vladislav Loktev, Alexander A. Lutovinov, Sergey V. Molkov, Alexander A. Mushtukov, Ajay Ratheesh, Nicole Rodriguez Cavero, James F. Steiner, Rashid A. Sunyaev, Sergey S. Tsygankov, Martin C. Weisskopf, Andrzej A. Zdziarski, Stefano Bianchi, Joe S. Bright, Nikolaj Bursov, Enrico Costa, Elise Egron, Javier A. Garcia, David A. Green, Mark Gurwell, Adam Ingram, Jari J. E. Kajava, Ruta Kale, Alex Kraus, Denys Malyshev, Frédéric Marin, Giorgio Matt, Michael McCollough, Ilya A. Mereminskiy, Nikolaj Nizhelsky, Giovanni Piano, Maura Pilia, Carlotta Pittori, Ramprasad Rao, Simona Righini, Paolo Soffitta, Anton Shevchenko, Jiri Svoboda, Francesco Tombesi, Sergei A. Trushkin, Peter Tsybulev, Francesco Ursini, Kinwah Wu, Iván Agudo, Lucio A. Antonelli, Matteo Bachetti, Luca Baldini, Wayne H. Baumgartner, Ronaldo Bellazzini, Stephen D. Bongiorno, Raffaella Bonino, Alessandro Brez, Niccolò Bucciantini, Simone Castellano, Elisabetta Cavazzuti, Chien-Ting Chen, Stefano Ciprini, Ettore Del Monte, Laura Di Gesu, Niccolò Di Lalla, Immacolata Donnarumma, Victor Doroshenko, Steven R. Ehlert, Teruaki Enoto, Yuri Evangelista, Sergio Fabiani, Riccardo Ferrazzoli, Shuichi Gunji, Kiyoshi Hayashida, Jeremy Heyl, Wataru Iwakiri, Svetlana G. Jorstad, Vladimir Karas, Fabian Kislat, Takao Kitaguchi, Jeffery J. Kolodziejczak, Luca Latronico, Ioannis Liodakis, Simone Maldera, Alberto Manfreda, Andrea Marinucci, Alan P. Marscher, Herman L. Marshall, Francesco Massaro, Ikuyuki Mitsuishi, Tsunefumi Mizuno, Michela Negro, Chi-Yung Ng, Stephen L. O’Dell, Nicola Omodei, Chiara Oppedisano, Alessandro Papitto, George G. Pavlov, Abel L. Peirson, Matteo Perri, Melissa Pesce-Rollins, Pierre-Olivier Petrucci, Andrea Possenti, Simonetta Puccetti, Brian D. Ramsey, John Rankin, Oliver Roberts, Roger W. Romani, Carmelo Sgrò, Patrick Slane, Gloria Spandre, Doug Swartz, Toru Tamagawa, Fabrizio Tavecchio, Roberto Taverna, Yuzuru Tawara, Allyn F. Tennant, Nicholas E. Thomas, Alessio Trois, Roberto Turolla, Jacco Vink, Fei Xie, Silvia Zane
The accretion of matter by compact objects can be inhibited by radiation pressure if the luminosity exceeds a critical value known as the Eddington limit. The discovery of ultraluminous X-ray sources has shown that accretion can proceed even when the apparent luminosity considerably exceeds this limit. A high apparent luminosity might be produced due to the geometric beaming of radiation by an outflow. The outflow half-opening angle, which determines the amplification due to beaming, has never been robustly constrained. Using the Imaging X-ray Polarimetry Explorer, we measured the X-ray polarization in the Galactic X-ray binary Cygnus X-3 (Cyg X-3). We found high, >20%, nearly energy-independent linear polarization orthogonal to the direction of the radio ejections. These properties unambiguously indicate the presence of a collimating outflow from the X-ray binary Cyg X-3 and constrain its half-opening angle to ≲15°. Thus, the source can be used as a laboratory for studying the supercritical accretion regime. This finding underscores the importance of X-ray polarimetry in advancing our understanding of accreting sources. The accretion geometry of X-ray binary Cygnus X-3 is determined here from IXPE observations. X-ray polarization reveals a narrow funnel with reflecting walls, which focuses emission, making Cyg X-3 appear as an ultraluminous X-ray source.
如果光度超过一个临界值，即爱丁顿极限，紧凑天体的物质吸积就会受到辐射压力的抑制。超亮 X 射线源的发现表明，即使表观光度大大超过这一极限，物质的吸积也能继续进行。高视光度可能是由于外流的几何射束辐射产生的。外流的半开角决定了光束的放大作用，但这个角度一直没有得到可靠的确定。利用成像 X 射线极化探测器，我们测量了银河系 X 射线双星天鹅座 X-3 （Cyg X-3）的 X 射线极化。我们发现了与射电抛射方向正交的、高达20%的、几乎与能量无关的线性极化。这些特性清楚地表明了 X 射线双星 Cyg X-3 的准直流的存在，并将其半开角约束为 ≲15°。因此，该星源可以作为研究超临界吸积机制的实验室。这一发现凸显了 X 射线偏振测量法在增进我们对吸积源的了解方面的重要性。
{"title":"Cygnus X-3 revealed as a Galactic ultraluminous X-ray source by IXPE","authors":"Alexandra Veledina, Fabio Muleri, Juri Poutanen, Jakub Podgorný, Michal Dovčiak, Fiamma Capitanio, Eugene Churazov, Alessandra De Rosa, Alessandro Di Marco, Sofia V. Forsblom, Philip Kaaret, Henric Krawczynski, Fabio La Monaca, Vladislav Loktev, Alexander A. Lutovinov, Sergey V. Molkov, Alexander A. Mushtukov, Ajay Ratheesh, Nicole Rodriguez Cavero, James F. Steiner, Rashid A. Sunyaev, Sergey S. Tsygankov, Martin C. Weisskopf, Andrzej A. Zdziarski, Stefano Bianchi, Joe S. Bright, Nikolaj Bursov, Enrico Costa, Elise Egron, Javier A. Garcia, David A. Green, Mark Gurwell, Adam Ingram, Jari J. E. Kajava, Ruta Kale, Alex Kraus, Denys Malyshev, Frédéric Marin, Giorgio Matt, Michael McCollough, Ilya A. Mereminskiy, Nikolaj Nizhelsky, Giovanni Piano, Maura Pilia, Carlotta Pittori, Ramprasad Rao, Simona Righini, Paolo Soffitta, Anton Shevchenko, Jiri Svoboda, Francesco Tombesi, Sergei A. Trushkin, Peter Tsybulev, Francesco Ursini, Kinwah Wu, Iván Agudo, Lucio A. Antonelli, Matteo Bachetti, Luca Baldini, Wayne H. Baumgartner, Ronaldo Bellazzini, Stephen D. Bongiorno, Raffaella Bonino, Alessandro Brez, Niccolò Bucciantini, Simone Castellano, Elisabetta Cavazzuti, Chien-Ting Chen, Stefano Ciprini, Ettore Del Monte, Laura Di Gesu, Niccolò Di Lalla, Immacolata Donnarumma, Victor Doroshenko, Steven R. Ehlert, Teruaki Enoto, Yuri Evangelista, Sergio Fabiani, Riccardo Ferrazzoli, Shuichi Gunji, Kiyoshi Hayashida, Jeremy Heyl, Wataru Iwakiri, Svetlana G. Jorstad, Vladimir Karas, Fabian Kislat, Takao Kitaguchi, Jeffery J. Kolodziejczak, Luca Latronico, Ioannis Liodakis, Simone Maldera, Alberto Manfreda, Andrea Marinucci, Alan P. Marscher, Herman L. Marshall, Francesco Massaro, Ikuyuki Mitsuishi, Tsunefumi Mizuno, Michela Negro, Chi-Yung Ng, Stephen L. O’Dell, Nicola Omodei, Chiara Oppedisano, Alessandro Papitto, George G. Pavlov, Abel L. Peirson, Matteo Perri, Melissa Pesce-Rollins, Pierre-Olivier Petrucci, Andrea Possenti, Simonetta Puccetti, Brian D. Ramsey, John Rankin, Oliver Roberts, Roger W. Romani, Carmelo Sgrò, Patrick Slane, Gloria Spandre, Doug Swartz, Toru Tamagawa, Fabrizio Tavecchio, Roberto Taverna, Yuzuru Tawara, Allyn F. Tennant, Nicholas E. Thomas, Alessio Trois, Roberto Turolla, Jacco Vink, Fei Xie, Silvia Zane","doi":"10.1038/s41550-024-02294-9","DOIUrl":"10.1038/s41550-024-02294-9","url":null,"abstract":"The accretion of matter by compact objects can be inhibited by radiation pressure if the luminosity exceeds a critical value known as the Eddington limit. The discovery of ultraluminous X-ray sources has shown that accretion can proceed even when the apparent luminosity considerably exceeds this limit. A high apparent luminosity might be produced due to the geometric beaming of radiation by an outflow. The outflow half-opening angle, which determines the amplification due to beaming, has never been robustly constrained. Using the Imaging X-ray Polarimetry Explorer, we measured the X-ray polarization in the Galactic X-ray binary Cygnus X-3 (Cyg X-3). We found high, >20%, nearly energy-independent linear polarization orthogonal to the direction of the radio ejections. These properties unambiguously indicate the presence of a collimating outflow from the X-ray binary Cyg X-3 and constrain its half-opening angle to ≲15°. Thus, the source can be used as a laboratory for studying the supercritical accretion regime. This finding underscores the importance of X-ray polarimetry in advancing our understanding of accreting sources. The accretion geometry of X-ray binary Cygnus X-3 is determined here from IXPE observations. X-ray polarization reveals a narrow funnel with reflecting walls, which focuses emission, making Cyg X-3 appear as an ultraluminous X-ray source.","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141436148","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 : 2024-06-20DOI: 10.1038/s41550-024-02314-8
Surveys aimed at different astronomy communities reveal persistent mental distress, widespread bullying and other unwanted behaviour. Marginalized groups are the most affected, causing continuous and damaging loss of talent from academia.
{"title":"The scourge of harassment in astronomy","authors":"","doi":"10.1038/s41550-024-02314-8","DOIUrl":"10.1038/s41550-024-02314-8","url":null,"abstract":"Surveys aimed at different astronomy communities reveal persistent mental distress, widespread bullying and other unwanted behaviour. Marginalized groups are the most affected, causing continuous and damaging loss of talent from academia.","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41550-024-02314-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141436064","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 : 2024-06-20DOI: 10.1038/s41550-024-02312-w
Paul Woods
{"title":"More than meets the eye","authors":"Paul Woods","doi":"10.1038/s41550-024-02312-w","DOIUrl":"10.1038/s41550-024-02312-w","url":null,"abstract":"","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141436029","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 : 2024-06-20DOI: 10.1038/s41550-024-02311-x
Bishwanath Gaire
{"title":"The Sun: solar dynamo located near the surface","authors":"Bishwanath Gaire","doi":"10.1038/s41550-024-02311-x","DOIUrl":"10.1038/s41550-024-02311-x","url":null,"abstract":"","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141436084","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}
Nanophase iron particles (npFe0) are generated on the surface of airless bodies by space weathering and can alter surficial optical properties substantially. However, the details of their formation pathways are still unclear. Here we use impact glasses returned from the Moon by Chang’e-5 to distinguish the relative contributions of solar wind irradiation and (micro)meteorites impacts to the production of different-sized npFe0. We show that solar wind irradiation can solely produce small npFe0, via implantation of solar wind ions into the topmost grain surfaces. On the other hand, (micro)meteorite impacts produce directly large npFe0 in melts, through impact-triggered disproportionation reaction or thermal decomposition. These nanoparticles are also capable to further coalesce into micrometre-sized Fe0 particles during impacts. These findings can help in predicting the space-weathering behaviour of regions exposed to different space environments.
{"title":"Separate effects of irradiation and impacts on lunar metallic iron formation observed in Chang’e-5 samples","authors":"Laiquan Shen, Rui Zhao, Chao Chang, Jihao Yu, Dongdong Xiao, Haiyang Bai, Zhigang Zou, Mengfei Yang, Weihua Wang","doi":"10.1038/s41550-024-02300-0","DOIUrl":"https://doi.org/10.1038/s41550-024-02300-0","url":null,"abstract":"<p>Nanophase iron particles (npFe<sup>0</sup>) are generated on the surface of airless bodies by space weathering and can alter surficial optical properties substantially. However, the details of their formation pathways are still unclear. Here we use impact glasses returned from the Moon by Chang’e-5 to distinguish the relative contributions of solar wind irradiation and (micro)meteorites impacts to the production of different-sized npFe<sup>0</sup>. We show that solar wind irradiation can solely produce small npFe<sup>0</sup>, via implantation of solar wind ions into the topmost grain surfaces. On the other hand, (micro)meteorite impacts produce directly large npFe<sup>0</sup> in melts, through impact-triggered disproportionation reaction or thermal decomposition. These nanoparticles are also capable to further coalesce into micrometre-sized Fe<sup>0</sup> particles during impacts. These findings can help in predicting the space-weathering behaviour of regions exposed to different space environments.</p>","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":null,"pages":null},"PeriodicalIF":14.1,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141430456","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 : 2024-06-20DOI: 10.1038/s41550-024-02291-y
A. Marino, C. Dehman, K. Kovlakas, N. Rea, J. A. Pons, D. Viganò
Neutron stars are the dense and highly magnetic relics of supernova explosions of massive stars. The quest to constrain the equation of state (EOS) of ultradense matter and thereby probe the behaviour of matter inside neutron stars is one of the core goals of modern physics and astrophysics. A promising method involves investigating the long-term cooling of neutron stars, comparing theoretical predictions with various sources at different ages. However, limited observational data, and uncertainties in source ages and distances, have hindered this approach. Here, by re-analysing XMM-Newton and Chandra data from dozens of thermally emitting isolated neutron stars, we have identified three sources with unexpectedly cold surface temperatures for their young ages. To investigate these anomalies, we conducted magneto-thermal simulations across diverse mass and magnetic fields, considering three different EOSs. We found that the ’minimal’ cooling model failed to explain the observations, regardless of the mass and the magnetic field, as validated by a machine learning classification method. The existence of these young cold neutron stars suggests that any dense matter EOS must be compatible with a fast cooling process at least in certain mass ranges, eliminating a significant portion of current EOS options according to recent meta-modelling analysis. The quest to understand the composition of neutron stars is a major challenge of modern physics. Here three isolated, young and cold neutron stars have been identified, showing how extremely dense matter can cool rapidly after a supernova explosion.
{"title":"Constraints on the dense matter equation of state from young and cold isolated neutron stars","authors":"A. Marino, C. Dehman, K. Kovlakas, N. Rea, J. A. Pons, D. Viganò","doi":"10.1038/s41550-024-02291-y","DOIUrl":"10.1038/s41550-024-02291-y","url":null,"abstract":"Neutron stars are the dense and highly magnetic relics of supernova explosions of massive stars. The quest to constrain the equation of state (EOS) of ultradense matter and thereby probe the behaviour of matter inside neutron stars is one of the core goals of modern physics and astrophysics. A promising method involves investigating the long-term cooling of neutron stars, comparing theoretical predictions with various sources at different ages. However, limited observational data, and uncertainties in source ages and distances, have hindered this approach. Here, by re-analysing XMM-Newton and Chandra data from dozens of thermally emitting isolated neutron stars, we have identified three sources with unexpectedly cold surface temperatures for their young ages. To investigate these anomalies, we conducted magneto-thermal simulations across diverse mass and magnetic fields, considering three different EOSs. We found that the ’minimal’ cooling model failed to explain the observations, regardless of the mass and the magnetic field, as validated by a machine learning classification method. The existence of these young cold neutron stars suggests that any dense matter EOS must be compatible with a fast cooling process at least in certain mass ranges, eliminating a significant portion of current EOS options according to recent meta-modelling analysis. The quest to understand the composition of neutron stars is a major challenge of modern physics. Here three isolated, young and cold neutron stars have been identified, showing how extremely dense matter can cool rapidly after a supernova explosion.","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141430557","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 : 2024-06-18DOI: 10.1038/s41550-024-02295-8
Jeremy Heyl, Victor Doroshenko, Denis González-Caniulef, Ilaria Caiazzo, Juri Poutanen, Alexander Mushtukov, Sergey S. Tsygankov, Demet Kirmizibayrak, Matteo Bachetti, George G. Pavlov, Sofia V. Forsblom, Christian Malacaria, Valery F. Suleimanov, Iván Agudo, Lucio Angelo Antonelli, Luca Baldini, Wayne H. Baumgartner, Ronaldo Bellazzini, Stefano Bianchi, Stephen D. Bongiorno, Raffaella Bonino, Alessandro Brez, Niccolò Bucciantini, Fiamma Capitanio, Simone Castellano, Elisabetta Cavazzuti, Chien-Ting Chen, Stefano Ciprini, Enrico Costa, Alessandra De Rosa, Ettore Del Monte, Laura Di Gesu, Niccolò Di Lalla, Alessandro Di Marco, Immacolata Donnarumma, Michal Dovčiak, Steven R. Ehlert, Teruaki Enoto, Yuri Evangelista, Sergio Fabiani, Riccardo Ferrazzoli, Javier A. Garcia, Shuichi Gunji, Kiyoshi Hayashida, Wataru Iwakiri, Svetlana G. Jorstad, Philip Kaaret, Vladimir Karas, Fabian Kislat, Takao Kitaguchi, Jeffery J. Kolodziejczak, Henric Krawczynski, Fabio La Monaca, Luca Latronico, Ioannis Liodakis, Simone Maldera, Alberto Manfreda, Frédéric Marin, Andrea Marinucci, Alan P. Marscher, Herman L. Marshall, Francesco Massaro, Giorgio Matt, Ikuyuki Mitsuishi, Tsunefumi Mizuno, Fabio Muleri, Michela Negro, C.-Y. Ng, Stephen L. O’Dell, Nicola Omodei, Chiara Oppedisano, Alessandro Papitto, Abel Lawrence Peirson, Matteo Perri, Melissa Pesce-Rollins, Pierre-Olivier Petrucci, Maura Pilia, Andrea Possenti, Simonetta Puccetti, Brian D. Ramsey, John Rankin, Ajay Ratheesh, Oliver J. Roberts, Roger W. Romani, Carmelo Sgrò, Patrick Slane, Paolo Soffitta, Gloria Spandre, Douglas A. Swartz, Toru Tamagawa, Fabrizio Tavecchio, Roberto Taverna, Yuzuru Tawara, Allyn F. Tennant, Nicholas E. Thomas, Francesco Tombesi, Alessio Trois, Roberto Turolla, Jacco Vink, Martin C. Weisskopf, Kinwah Wu, Fei Xie, Silvia Zane
In an accreting X-ray pulsar, a neutron star accretes matter from a companion star through an accretion disk. The magnetic field of the rotating neutron star disrupts the inner edge of the disk, funnelling the gas to flow onto the poles on its surface. Hercules X-1 is a prototypical persistent X-ray pulsar about 7 kpc from Earth. Its emission varies on three distinct timescales: the neutron star rotates every 1.2 s, it is eclipsed by its companion each 1.7 d, and the system exhibits a superorbital period of 35 d, which has remained stable since its discovery. Several lines of evidence point to the source of this variation as the precession of the accretion disk or that of the neutron star. Despite the many hints over the past 50 yr, the precession of the neutron star itself has yet not been confirmed or refuted. X-ray polarization measurements (probing the spin geometry of Her X-1) with the Imaging X-ray Polarimetry Explorer suggest that free precession of the neutron star crust sets the 35 d period; this has the important implication that its crust is somewhat asymmetric by a few parts per ten million. IXPE has revealed how the spin of the accreting neutron star Hercules X-1 changes in three dimensions. The spin axis of the star moves both through the star and across the sky, hinting that the crust of the star is asymmetric by almost one part in a million.
在吸积 X 射线脉冲星中，一颗中子星通过吸积盘吸积来自伴星的物质。旋转的中子星的磁场破坏了吸积盘的内缘，使气体流向吸积盘表面的两极。海格力斯 X-1 是一颗典型的持续 X 射线脉冲星，距离地球约 7 kpc。它的发射在三个不同的时间尺度上变化：中子星每 1.2 秒旋转一次，它每 1.7 天被其伴星食一次，该系统显示出 35 天的超轨道周期，自发现以来一直保持稳定。一些证据表明，这种变化的来源是吸积盘或中子星的前向运动。尽管在过去的 50 年中出现了许多暗示，但中子星本身的前摄动尚未得到证实或反驳。利用成像 X 射线偏振探测仪进行的 X 射线偏振测量（探测 Her X-1 的自旋几何）表明，中子星外壳的自由前冲设定了 35 d 周期；这具有重要的含义，即其外壳在某种程度上是不对称的，为千万分之几。
{"title":"Complex rotational dynamics of the neutron star in Hercules X-1 revealed by X-ray polarization","authors":"Jeremy Heyl, Victor Doroshenko, Denis González-Caniulef, Ilaria Caiazzo, Juri Poutanen, Alexander Mushtukov, Sergey S. Tsygankov, Demet Kirmizibayrak, Matteo Bachetti, George G. Pavlov, Sofia V. Forsblom, Christian Malacaria, Valery F. Suleimanov, Iván Agudo, Lucio Angelo Antonelli, Luca Baldini, Wayne H. Baumgartner, Ronaldo Bellazzini, Stefano Bianchi, Stephen D. Bongiorno, Raffaella Bonino, Alessandro Brez, Niccolò Bucciantini, Fiamma Capitanio, Simone Castellano, Elisabetta Cavazzuti, Chien-Ting Chen, Stefano Ciprini, Enrico Costa, Alessandra De Rosa, Ettore Del Monte, Laura Di Gesu, Niccolò Di Lalla, Alessandro Di Marco, Immacolata Donnarumma, Michal Dovčiak, Steven R. Ehlert, Teruaki Enoto, Yuri Evangelista, Sergio Fabiani, Riccardo Ferrazzoli, Javier A. Garcia, Shuichi Gunji, Kiyoshi Hayashida, Wataru Iwakiri, Svetlana G. Jorstad, Philip Kaaret, Vladimir Karas, Fabian Kislat, Takao Kitaguchi, Jeffery J. Kolodziejczak, Henric Krawczynski, Fabio La Monaca, Luca Latronico, Ioannis Liodakis, Simone Maldera, Alberto Manfreda, Frédéric Marin, Andrea Marinucci, Alan P. Marscher, Herman L. Marshall, Francesco Massaro, Giorgio Matt, Ikuyuki Mitsuishi, Tsunefumi Mizuno, Fabio Muleri, Michela Negro, C.-Y. Ng, Stephen L. O’Dell, Nicola Omodei, Chiara Oppedisano, Alessandro Papitto, Abel Lawrence Peirson, Matteo Perri, Melissa Pesce-Rollins, Pierre-Olivier Petrucci, Maura Pilia, Andrea Possenti, Simonetta Puccetti, Brian D. Ramsey, John Rankin, Ajay Ratheesh, Oliver J. Roberts, Roger W. Romani, Carmelo Sgrò, Patrick Slane, Paolo Soffitta, Gloria Spandre, Douglas A. Swartz, Toru Tamagawa, Fabrizio Tavecchio, Roberto Taverna, Yuzuru Tawara, Allyn F. Tennant, Nicholas E. Thomas, Francesco Tombesi, Alessio Trois, Roberto Turolla, Jacco Vink, Martin C. Weisskopf, Kinwah Wu, Fei Xie, Silvia Zane","doi":"10.1038/s41550-024-02295-8","DOIUrl":"10.1038/s41550-024-02295-8","url":null,"abstract":"In an accreting X-ray pulsar, a neutron star accretes matter from a companion star through an accretion disk. The magnetic field of the rotating neutron star disrupts the inner edge of the disk, funnelling the gas to flow onto the poles on its surface. Hercules X-1 is a prototypical persistent X-ray pulsar about 7 kpc from Earth. Its emission varies on three distinct timescales: the neutron star rotates every 1.2 s, it is eclipsed by its companion each 1.7 d, and the system exhibits a superorbital period of 35 d, which has remained stable since its discovery. Several lines of evidence point to the source of this variation as the precession of the accretion disk or that of the neutron star. Despite the many hints over the past 50 yr, the precession of the neutron star itself has yet not been confirmed or refuted. X-ray polarization measurements (probing the spin geometry of Her X-1) with the Imaging X-ray Polarimetry Explorer suggest that free precession of the neutron star crust sets the 35 d period; this has the important implication that its crust is somewhat asymmetric by a few parts per ten million. IXPE has revealed how the spin of the accreting neutron star Hercules X-1 changes in three dimensions. The spin axis of the star moves both through the star and across the sky, hinting that the crust of the star is asymmetric by almost one part in a million.","PeriodicalId":18778,"journal":{"name":"Nature Astronomy","volume":null,"pages":null},"PeriodicalIF":12.9,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141334307","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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