Astronomische Nachrichten最新文献

{"title":"Issue Information: Astron. Nachr. 1/2025","authors":"","doi":"10.1002/asna.20259001","DOIUrl":"https://doi.org/10.1002/asna.20259001","url":null,"abstract":"","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asna.20259001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143110428","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":"Cover Picture: Astron. Nachr. 1/2025","authors":"S. Friedrich,&nbsp;C. Maitra,&nbsp;K. Dennerl,&nbsp;A. Schwope,&nbsp;K. Werner,&nbsp;B. Stelzer","doi":"10.1002/asna.20259010","DOIUrl":"https://doi.org/10.1002/asna.20259010","url":null,"abstract":"<p>Hunting for white dwarfs in eROSITA surveys 1-4 with special processing. The Gaia color-magnitude diagram shows all white dwarf candidates from the Gaia white dwarf catalogue (Gentile Fusillo et al. 2021), colour-coded with the probability of being a white dwarf. Black circles mark sources in the ROSAT white dwarf catalogue (Fleming et al. 1996) that match entries in the Gaia white dwarf catalogue (light blue crosses indicate those in the German half of the eROSITA sky). Orange crosses mark eROSITA sources with a hardness ratio of ≤ −0.94 and with counterparts in the Gaia white dwarf catalogue. Those highlighted with a dark green circle have a probability larger than 90 % of being a white dwarf in that catalogue. The cooling tracks of white dwarfs with masses between 0.4 and 1.2 solar masses are shown as gray lines in steps of 0.1 solar masses (top to bottom). For more details see the related paper by S. Friedrich et al. published in this issue e240139.\u0000\u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asna.20259010","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143110434","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":"JWST Imaging of the Closest Globular Clusters—V. The White Dwarfs Cooling Sequence of M4","authors":"Luigi R. Bedin,&nbsp;Mattia Libralato,&nbsp;Maurizio Salaris,&nbsp;Domenico Nardiello,&nbsp;Michele Scalco,&nbsp;Massimo Griggio,&nbsp;Jay Anderson,&nbsp;Pierre Bergeron,&nbsp;Andrea Bellini,&nbsp;Roman Gerasimov,&nbsp;Adam J. Burgasser,&nbsp;Daniel Apai","doi":"10.1002/asna.20240125","DOIUrl":"https://doi.org/10.1002/asna.20240125","url":null,"abstract":"<p>We combine infrared (IR) observations collected by the <i>James Webb Space Telescope</i> with optical deep images by the <i>Hubble Space Telescope</i> taken ~20 years earlier to compute proper-motion membership for the globular cluster (GC) M4 (NGC 6121) along its entire white dwarf (WD) cooling sequence (CS). These new IR observations allow us, for only the second time in a GC, to compare WD models with observations over a wide range of wavelengths, constraining fundamental astrophysical properties of WDs. Furthermore, we investigate the presence of WDs with IR excess along the WD CS of M4, similar to the recent study conducted on the GC NGC 6397. We also determine the age difference between M4 and NGC 6397 by comparing the absolute F150W2 magnitudes of the luminosity function peak at the bottom of the observed WD CS and find that M4 is slightly younger, by 0.8 ± 0.5 Gyr.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 2","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asna.20240125","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143490047","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":"Quark/Hybrid Stars Within Perturbative QCD in View of the GW170817 Event","authors":"Fábio Köpp,&nbsp;Jorge Ernesto Horvath,&nbsp;Dimiter Hadjimichef,&nbsp;César A. Zen Vasconcellos","doi":"10.1002/asna.20240136","DOIUrl":"https://doi.org/10.1002/asna.20240136","url":null,"abstract":"<div>\u0000 \u0000 <p>In this study, we examine the implications of perturbative Quantum Chromodynamics (pQCD) extrapolated from higher energies down to the neutron star range, as applied to hybrid stars. In describing the hybrid star, we represent the quark phase by pQCD, and the hadronic phase using the APR4 equation of state (EoS). The phase transition itself is modeled using the Maxwell construction. We hypothesize as a consequence of our work that the central compact object XMMU J173203.3, could be a quark star described by the pQCD EoS. Analysis of the mass-radius diagrams and the dimensionless tidal deformability are performed. The results obtained for the latter in the case of hybrid star models are consistent with observations from the GW170817 event; however, they do not meet the <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>M</mi>\u0000 <mo>∼</mo>\u0000 <mn>2</mn>\u0000 <mspace></mspace>\u0000 <msub>\u0000 <mi>M</mi>\u0000 <mo>⊙</mo>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ Msim 2kern0.1em {M}_{odot } $$</annotation>\u0000 </semantics></math> constraint.</p>\u0000 </div>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 3-4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144207020","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":"The B±-Meson Production in High Energy pp Collisions in the Color Dipole Transverse Momentum Representation","authors":"G. Sampaio dos Santos,&nbsp;G. Gil da Silveira,&nbsp;Magno V. T. Machado","doi":"10.1002/asna.20250007","DOIUrl":"https://doi.org/10.1002/asna.20250007","url":null,"abstract":"<div>\u0000 \u0000 <p>The color dipole formalism in the transverse momentum framework together with the unintegrated gluon distributions is considered to obtain the <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>B</mi>\u0000 <mo>±</mo>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ {B}^{pm } $$</annotation>\u0000 </semantics></math> differential cross sections in <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>pp</mi>\u0000 </mrow>\u0000 <annotation>$$ pp $$</annotation>\u0000 </semantics></math> collisions. The theoretical predictions for the <i>B</i>^±-meson production assume the center-of-mass energy of the Large Hadron Collider and the rapidities available at the LHCb experiment. The results are compared with the corresponding measurements in terms of the meson transverse momentum.</p>\u0000 </div>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 3-4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144207019","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":"Investigating Phase Transitions in Hybrid Stars Using the vMIT Bag Model and the QHD-II Model","authors":"Fábio Köpp,&nbsp;Jorge Ernesto Horvath,&nbsp;Dimiter Hadjimichef,&nbsp;César A. Zen Vasconcellos","doi":"10.1002/asna.20250006","DOIUrl":"https://doi.org/10.1002/asna.20250006","url":null,"abstract":"<div>\u0000 \u0000 <p>In this contribution, the global properties of hybrid compact stars resulting from a phase transition between hadronic matter and an interior composed of up, down, and strange quarks, based on a Maxwell construction, are studied. For the equation of state of the hadronic matter, we employ a covariant density functional theory within the framework of relativistic mean field theory, specifically the Quantum Hadrodynamics-II (QHD-II) model, with parameters determined using the <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>NL</mi>\u0000 <msup>\u0000 <mn>3</mn>\u0000 <mo>*</mo>\u0000 </msup>\u0000 <mrow>\u0000 <mi>ω</mi>\u0000 <mi>ρ</mi>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation>$$ NL{3}^{ast}omega rho $$</annotation>\u0000 </semantics></math> parametrization. For the quark matter in the stellar core, we use the improved vMIT bag model, which incorporates repulsive interactions mediated by vector mesons, a crucial feature for describing stable and massive hybrid stellar configurations in agreement with recent observations of pulsars with masses above <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>2.0</mn>\u0000 <mspace></mspace>\u0000 <msub>\u0000 <mi>M</mi>\u0000 <mo>⊙</mo>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ 2.0kern0.1em {mathrm{M}}_{odot } $$</annotation>\u0000 </semantics></math>.</p>\u0000 </div>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 3-4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206989","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":"Modeling the Emission and Polarization Properties of Pulsating Ultraluminous X-Ray Sources","authors":"S. Conforti,&nbsp;L. Zampieri,&nbsp;R. Taverna,&nbsp;R. Turolla,&nbsp;N. Brice,&nbsp;F. Pintore,&nbsp;G. L. Israel","doi":"10.1002/asna.20240129","DOIUrl":"https://doi.org/10.1002/asna.20240129","url":null,"abstract":"<p>Pulsating Ultraluminous X-ray Sources (PULXs) are a class of extragalactic sources with high X-ray luminosity, in excess of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mn>10</mn>\u0000 <mn>39</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ {10}^{39} $$</annotation>\u0000 </semantics></math> erg <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>s</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ {mathrm{s}}^{-1} $$</annotation>\u0000 </semantics></math>, and showing pulsations that associate them with neutron stars accreting at a super-Eddington rate. A simplified model is presented, which describes the thermal emission from an accreting, highly magnetized neutron star and includes the contributions from an accretion disk and an accretion envelope surrounding the star magnetosphere. Through numerical calculations, we determine the flux, pulsed fractions, polarization degree, and polarization angle considering various viewing geometries. The model is confronted with the <i>XMM-Newton</i> spectra of M51 ULX-7, and the best fitting viewing geometries are estimated. A measurement of the polarization observables, which will be available with future facilities, along with spectroscopic data obtained with <i>XMM-Newton</i>, will provide considerable additional information on these sources.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asna.20240129","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119540","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":"Superhabitable Planets Around Mid-Type K Dwarf Stars Enhance Simulated JWST Observability and Surface Habitability","authors":"Iva Vilović,&nbsp;Jayesh Goyal,&nbsp;René Heller,&nbsp;Fanny Marie von Schauenburg","doi":"10.1002/asna.20240081","DOIUrl":"https://doi.org/10.1002/asna.20240081","url":null,"abstract":"<p>In our search for life beyond the Solar System, certain planetary bodies may be more conducive to life than Earth. However, the observability of these “superhabitable” (SH) planets in the habitable zones around K dwarf stars has not been fully modeled. This study addresses this gap by modeling the atmospheres of SH exoplanets. We employed the 1D model <i>Atmos</i> to define the SH parameter space, <i>POSEIDON</i> to calculate synthetic transmission spectra, and <i>PandExo</i> to simulate JWST observations. Our results indicate that planets orbiting mid-type K dwarfs, receiving 80% of Earth's solar flux, are optimal for life. These planets sustain temperate surfaces with moderate CO₂ levels, unlike those receiving 60% flux, where necessarily higher CO₂ levels could hinder biosphere development. Moreover, they are easier to observe, requiring significantly fewer transits for biosignature detection compared with Earth-like planets around Sun-like stars. For instance, detecting biosignature pairs like oxygen and methane from 30 pc would require 150 transits (43 years) for a SH planet, versus over 1700 transits (~1700 years) for Earth-like planets. While such observation times lie outside of JWST mission timescales, our study underscores the necessity of next-generation telescopes and provides valuable targets for future observations with, for example, the ELT.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 2","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asna.20240081","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489794","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":"Uncertainties in Ground-Based Visual Double Star Measures","authors":"Roderick R. Letchford,&nbsp;Graeme L. White","doi":"10.1002/asna.20240086","DOIUrl":"https://doi.org/10.1002/asna.20240086","url":null,"abstract":"<p>Stellar masses are found from the orbital elements of binary systems which are, in turn, computed from weighted astrometric measures. Astrometric measures of double stars (their position angle and separation) rarely include uncertainties, and published binary star orbits rarely include the weighting systems used in the determination of the orbital elements. Here we propose a simple method for estimating uncertainties of ground-based measures of visual double stars based on precision space-based astrometry of optical (not binary) double stars, which can be used as unbiased weights for all double star measures. The precision of ground-based measures is examined as (i) a function of the date of observation, (ii) the telescope aperture, and (iii) the instrumentation (technique) used at the telescope. We also note in the Appendix, 19 pairs that are incorrectly described in Lin2 and six rectilinear pairs that may display curved motion.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 2","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asna.20240086","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489673","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":"Where in the Milky Way Do Exoplanets Preferentially Form?","authors":"Joana Teixeira,&nbsp;Vardan Adibekyan,&nbsp;Diego Bossini","doi":"10.1002/asna.20240076","DOIUrl":"https://doi.org/10.1002/asna.20240076","url":null,"abstract":"<div>\u0000 \u0000 <p>Exoplanets are detected around stars of different ages and birthplaces within the Galaxy. The aim of this work is to infer the Galactic birth radii (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>r</mi>\u0000 <mtext>birth</mtext>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ {r}_{mathrm{birth}} $$</annotation>\u0000 </semantics></math>) of stars and, consequently, their planets, with the ultimate goal of studying the Galactic aspects of exoplanet formation. We used photometric, spectroscopic, and astrometric data to estimate the stellar ages of two samples of stars hosting planets and, for comparison, a sample of stars without detected planets. The <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>r</mi>\u0000 <mtext>birth</mtext>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ {r}_{mathrm{birth}} $$</annotation>\u0000 </semantics></math> of exoplanets were inferred by projecting stars back to their birth positions based on their estimated age and metallicity [Fe/H]. We find that stars hosting planets have higher [Fe/H], are younger, and have smaller <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>r</mi>\u0000 <mtext>birth</mtext>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ {r}_{mathrm{birth}} $$</annotation>\u0000 </semantics></math> compared to stars without detected planets. In particular, stars hosting high-mass planets show higher [Fe/H], are younger, and have smaller <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>r</mi>\u0000 <mtext>birth</mtext>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ {r}_{mathrm{birth}} $$</annotation>\u0000 </semantics></math> than stars hosting low-mass planets. We show that the formation efficiency of planets, calculated as the relative frequency of planetary systems, decreases with the galactocentric distance, which relationship is stronger for high-mass planets than for low-mass planets. Additionally, we find that (i) the formation efficiency of high-mass planets increases with time and encompasses a larger galactocentric distance over time; (ii) the formation efficiency of low-mass planets shows a slight increase between the ages of 4 and 8 Gyr and also encompasses a larger galactocentric distance over time; and (iii) stars without detected planets appear to form at larger galactocentric distances over time. We conclude that the formation of exoplanets throughout the Galaxy follows the Galactic chemical evolution, for which our results are in agreement with the observed negative interstellar medium (ISM)","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 2","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489672","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}