{"title":"Fritz Krause (1927–2024)","authors":"Günther Rüdiger","doi":"10.1002/asna.20240048","DOIUrl":"10.1002/asna.20240048","url":null,"abstract":"<p>Fritz Krause came from the early mathematics school in Jena and attended physics lectures by Friedrich Hund. After completing his doctorate, he joined Max Steenbeck at the nearby Academy Institute for Magnetohydrodynamics in 1958, where he developed the mathematical foundations of the dynamo theory of cosmic magnetic fields. The publication “Berechnung der mittleren Lorentz-Feldstärke <<b>u</b>' × <b>B</b>'> für ein elektrisch leitendes Medium in turbulenter, durch Corioliskräfte beeinflußter Bewegung” with M. Steenbeck and K.-H. Rädler in Zeitschrift für Naturforschung in 1966 was by far the internationally most successful journal publication in the history of science in the GDR.</p><p>Krause arrived at the Friedrich Schiller University in Jena at the age of 18 as a result of the events of the WW2. Born the youngest in Groß Särchen in Niederlausitz, which is now part of Poland, the Krauses had to leave their homeland in 1945 and reached Friedrichroda in Thüringen as a refugee family. Fritz studied mathematics in Jena from as early as 1946, although he was allowed to take his university entrance qualification retrospectively in the second year at a special FSU institution. Becoming a biologist was another unrealized career aspiration which remained present in many of his later hobby activities. He completed the mathematics degree in 1951 under Walter Brödel, in whose Institut für Reine Mathematik he also wrote his dissertation “Zur konformen Geometrie der dreifachen Orthogonalsysteme.” In 1958, the year he graduated, Irmgard Schröder and Fritz Krause started a family, which soon included their sons Matthias und Peter.</p><p>After a brief period as director of the Geomagnetisches Institut der Akademie der Wissenschaften zu Berlin on Potsdam/Telegraphenberg, Krause became head of the “Kosmische Magnetfelder” department at the Astrophysikalisches Observatorium Potsdam, later at the Zentralinstitut für Astrophysik, where hydrodynamic and thermodynamic applications were also developed. The original German-language publications from Jena were translated into English by P. H. Roberts and M. Stix soon after they appeared and have since become one of the cornerstones of the new scientific branch of dynamo theory. Some of the terms introduced at that time, such as α effect or helicity, are still used today in modern publications. Together with K.-H. Rädler, he wrote the widely acclaimed monograph “Mean-field magnetohydrodynamics and dynamo theory” in 1980, the Observatory's first book publication since the end of WW2. In the 70s, we were often visited by Paul H. Roberts from University of Newcastle upon Tyne—who could hardly be beaten at table tennis—also in order to break through the isolation of the Potsdam staff. That also was the time when both were involved in ongoing scientific disputes as a team. The first international conference on the Telegraphenberg for decades, “Stellar and planetary magnetic fields” in 1983, was a final stage in the o","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"345 5","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asna.20240048","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141113988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
C. Pinto, J. F. Steiner, A. Bodaghee, P. Chakraborty, M. Sobolewska, D. R. Pasham, A. Ogorzalek, J. Zuhone, A. Bogdan, M. Vogelsberger
{"title":"Probing extreme black-hole outflows on short timescales via high spectral-resolution x-ray imagers","authors":"C. Pinto, J. F. Steiner, A. Bodaghee, P. Chakraborty, M. Sobolewska, D. R. Pasham, A. Ogorzalek, J. Zuhone, A. Bogdan, M. Vogelsberger","doi":"10.1002/asna.20240027","DOIUrl":"10.1002/asna.20240027","url":null,"abstract":"<p>We investigate outflows and the physics of super-Eddington versus sub-Eddington regimes in black hole systems. Our focus is on prospective science using next-generation high-resolution soft x-ray instruments. We highlight the properties of black hole ultraluminous x-ray source (ULX) systems in particular. Owing to scale invariance in accreting black holes, ULX accretion properties, including their outflows, inform our understanding not only of the closely related population of (similar-mass) x-ray binary systems but also of tidal disruption events (TDEs) around supermassive black holes. A subsample of TDEs are likely to transcend super-Eddington to sub-Eddington regimes as they evolve, offering an important unifying analog to ULXs and sub-Eddington x-ray binaries. We demonstrate how next-generation soft x-ray observations with resolving power <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>≳</mo>\u0000 <mn>1000</mn>\u0000 </mrow>\u0000 <annotation>$$ gtrsim 1000 $$</annotation>\u0000 </semantics></math> and collecting area <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>≳</mo>\u0000 <mn>1000</mn>\u0000 <mspace></mspace>\u0000 <msup>\u0000 <mi>cm</mi>\u0000 <mn>2</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ gtrsim 1000kern0.5em {mathrm{cm}}^2 $$</annotation>\u0000 </semantics></math> can simultaneously identify ultrafast and more typical wind components, distinguish between different wind mechanisms, and constrain changing wind properties over characteristic variability timescales.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"345 6-7","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140941768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Manfred Küker, S. P. Järvinen, S. Hubrig, Ilya Ilyin, M. Schöller
{"title":"Cover Picture: Astron. Nachr. 4/2024","authors":"Manfred Küker, S. P. Järvinen, S. Hubrig, Ilya Ilyin, M. Schöller","doi":"10.1002/asna.20249013","DOIUrl":"https://doi.org/10.1002/asna.20249013","url":null,"abstract":"<p>Variability of the H<i>α</i> emission line profile of the magnetic O-type star HD 54897 over one decade, from 2014 to 2024. In the left panels, each profile is plotted with a different color as is indicated in the legend, showing the corresponding observing date and instrument used: H: HARPS, E: ESPaDOnS, U: UVES, and P: PEPSI. The upper panel shows the profiles based on the spectra observed recently, while the bottom panel shows all available profiles published previously. The right panel shows the same data in a color scale plot. The red color corresponds to the strongest emission, while the blue color shows the H<i>α</i> line wings appearing in absorption. The observed H<i>α</i> emission is thought to originatein a disk of increased gas density in the equatorial plane of the magnetic field. For details see the article by Küker <i>et al</i>., this issue, e230169.\u0000\u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure>\u0000 </p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"345 4","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asna.20249013","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140844758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Nikoleta Ilić, Katja Poppenhaeger, Anna Barbara Queiroz, Cristina Chiappini
{"title":"Constraining stellar tidal quality factors from planet-induced stellar spin-up","authors":"Nikoleta Ilić, Katja Poppenhaeger, Anna Barbara Queiroz, Cristina Chiappini","doi":"10.1002/asna.20230132","DOIUrl":"10.1002/asna.20230132","url":null,"abstract":"<p>The dynamical evolution of tight star-planet systems is influenced by tidal interactions between the star and the planet, as was shown recently. The rate at which spins and orbits in such a system evolve depends on the stellar and planetary tidal dissipation efficiency. Here, we present a method to constrain the modified tidal quality factor <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msubsup>\u0000 <mi>Q</mi>\u0000 <mo>*</mo>\u0000 <mo>′</mo>\u0000 </msubsup>\u0000 </mrow>\u0000 <annotation>$$ {Q}_{ast}^{prime } $$</annotation>\u0000 </semantics></math> of a planet-hosting star whose rotational evolution has been altered by its planet through angular momentum transfer from the planetary orbital motion to the rotation of the stellar convective zone. The altered rotation is estimated from an observed discrepancy of magnetic activity of the planet-hosting star and a coeval companion star, that is, this method is applicable to star-planet systems with wide stellar companions. We give an example of the planet-hosting wide binary system HD189733 and find that the planet host's modified tidal quality factor is constrained to be <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msubsup>\u0000 <mi>Q</mi>\u0000 <mo>*</mo>\u0000 <mo>′</mo>\u0000 </msubsup>\u0000 <mo>≤</mo>\u0000 <mn>2.33</mn>\u0000 <mo>×</mo>\u0000 <msup>\u0000 <mn>10</mn>\u0000 <mn>7</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ {Q}_{ast}^{prime}le 2.33times {10}^7 $$</annotation>\u0000 </semantics></math>.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"345 5","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asna.20230132","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140837283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
{"title":"Heating of millisecond pulsars by magnetic field decay","authors":"U. Geppert","doi":"10.1002/asna.20240032","DOIUrl":"10.1002/asna.20240032","url":null,"abstract":"<p>Millisecond pulsars (MSPs) are believed to be very old neutron stars (NSs) whose age may exceed significantly <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mn>10</mn>\u0000 <mn>8</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ {10}^8 $$</annotation>\u0000 </semantics></math> years. Although cooling scenarios of isolated NSs predict for that age a surface temperature <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>T</mi>\u0000 <mi>s</mi>\u0000 </msub>\u0000 <mo>~</mo>\u0000 <msup>\u0000 <mn>10</mn>\u0000 <mn>4</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ {T}_ssim {10}^4 $$</annotation>\u0000 </semantics></math> K, observations of the nearest MSP J0437-4715 indicate <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>T</mi>\u0000 <mi>s</mi>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ {T}_s $$</annotation>\u0000 </semantics></math> well above that value. Besides the heating of the polar cap surface by backflowing charged particles, Joule heating in the crust can contribute to the overall heat budget of MSPs. Because the dipolar field component, derived from <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>P</mi>\u0000 </mrow>\u0000 <annotation>$$ P $$</annotation>\u0000 </semantics></math> and <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mover>\u0000 <mi>P</mi>\u0000 <mo>˙</mo>\u0000 </mover>\u0000 </mrow>\u0000 <annotation>$$ dot{P} $$</annotation>\u0000 </semantics></math> measurements, is much too weak for remarkable heating, smaller-scale structures should be analyzed to understand whether they can supply the demanded heat. For this purpose, we study the small-scale field structure of radio pulsars. Magnetic field components, significantly stronger than the dipolar one, may exist especially at the surface of MSPs. We assign upper limits to the strength of single-field components up to a multipolarity of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>l</mi>\u0000 <mo>=</mo>\u0000 <mn>10</mn>\u0000 </mrow>\u0000 <annotation>$$ l=10 $$</annotation>\u0000 </semantics></math> and the corresponding deviations from axial symmetry <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>m</mi>\u0000 <mo>≤</mo>\u0000 <mi>l</mi>\u0000 </mrow>\u0000 <annotation>$$ mle l $$</annotation>\u0000 <","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"345 5","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140626546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Jaroslav Merc, Peter Velez, Stéphane Charbonnel, Olivier Garde, Pascal Le Dû, Lionel Mulato, Thomas Petit, Jan Skowron
{"title":"Gaia23ckh: Symbiotic outburst of the assumed Mira variable V390 Sco","authors":"Jaroslav Merc, Peter Velez, Stéphane Charbonnel, Olivier Garde, Pascal Le Dû, Lionel Mulato, Thomas Petit, Jan Skowron","doi":"10.1002/asna.20240017","DOIUrl":"10.1002/asna.20240017","url":null,"abstract":"<p>The poorly studied variable star V390 Sco, previously classified as a Mira pulsator, was detected in a brightening event by the ESA <i>Gaia</i> satellite in September 2023. This work presents an analysis of available archival multifrequency photometric data of this target, along with our spectroscopic observations. Our findings lead to the conclusion that V390 Sco is a new symbiotic star identified by <i>Gaia</i>, currently undergoing a classical symbiotic outburst. Additionally, we uncovered three prior outbursts of this system through archival photometry. The outbursts recur approximately every 2330–2400 days, and we hypothesize the periastron passage in an eccentric orbit may trigger them, similarly to the case of BX Mon, DD Mic, or MWC 560. A detailed investigation into the nature of the donor star suggested that V390 Sco is an S-type symbiotic star, likely hosting a less evolved, semiregularly pulsating giant donor, but not a Mira variable.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"345 5","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140387784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Michele Scalco, Roman Gerasimov, Luigi R. Bedin, Enrico Vesperini, Domenico Nardiello, Maurizio Salaris, Adam Burgasser, Jay Anderson, Mattia Libralato, Andrea Bellini, Piero Rosati
{"title":"The HST Large Programme on NGC 6752 - V. Differences in luminosity and mass function among stellar populations","authors":"Michele Scalco, Roman Gerasimov, Luigi R. Bedin, Enrico Vesperini, Domenico Nardiello, Maurizio Salaris, Adam Burgasser, Jay Anderson, Mattia Libralato, Andrea Bellini, Piero Rosati","doi":"10.1002/asna.20240018","DOIUrl":"10.1002/asna.20240018","url":null,"abstract":"<p>We exploit the astro-photometric dataset of the multi-epoch infrared parallel field of a <i>Hubble Space Telescope</i> Large Programme aimed at studying the faintest stars of the globular cluster NGC 6752 to determine the luminosity and mass functions of the multiple stellar populations of this cluster. Thanks to the measurement of proper motions and deeper completeness, the results presented in this paper represent a significant improvement over those of previous studies. We successfully derived membership probabilities reaching stars as faint as <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>m</mi>\u0000 <mrow>\u0000 <mi>F</mi>\u0000 <mn>160</mn>\u0000 <mi>W</mi>\u0000 </mrow>\u0000 </msub>\u0000 <mo>∼</mo>\u0000 <mn>25</mn>\u0000 </mrow>\u0000 <annotation>$$ {m}_{mathrm{F}160mathrm{W}}sim 25 $$</annotation>\u0000 </semantics></math>, allowing us to reliably distinguish the three main stellar populations detected within this cluster. We employed a new set of model isochrones that have been individually fit to the colour–magnitude diagram of each population. We present a comprehensive analysis of the luminosity and mass functions for three stellar populations within NGC 6752. Notably, our findings reveal differences in the present-day luminosity and mass functions of first-generation and second-generation stars; these differences are consistent with the manifestation of the effects of dynamical processes acting on populations with different initial spatial distributions. Finally, we publicly release the catalogues with positions, photometry, proper motions and memberships probabilities, as well as the stacked-image atlases and all newly calculated stellar models.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"345 5","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140371919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
{"title":"Cover Picture: Astron. Nachr. 2/2024","authors":"Zhengli Wang, Jiguang Lu, Jingchen Jiang, Shunshun Cao, Weiyang Wang, Enwei Liang, Renxin Xu","doi":"10.1002/asna.20249012","DOIUrl":"https://doi.org/10.1002/asna.20249012","url":null,"abstract":"<p>It has been proposed that the building blocks of pulsar matter could be ‘an’, strangeons analogy of atomic nucleons but with negative strangeness. A bare strangeon star should not have a smooth surface, but be covered with small hills (‘zits’), as indicated by red spots in this schematic illustration. These zits on the pulsar surface might be responsible for the magnetospheric activity and the mysterious coherent radio emission, as discussed in the contribution by Xu and Wang, this issue, p. e230153. Zits may also be responsible for the significantly non-symmetrical sparking discovered in the 110-min polarization observation of pulsar PSR B0950+08 targeted with China's Five-hundred-meter Aperture Spherical radio Telescope, FAST. Details can be found in the contribution by Wang et al., this issue, e240010.\u0000\u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure>\u0000 </p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"345 2-3","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asna.20249012","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140209598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}