arXiv - PHYS - Solar and Stellar Astrophysics最新文献

{"title":"Photospheric signatures of CME onset","authors":"Aslam Ottupara, David MacTaggart, Tom Williams, Lyndsay Fletcher, Paolo Romano","doi":"arxiv-2409.07261","DOIUrl":"https://doi.org/arxiv-2409.07261","url":null,"abstract":"Coronal mass ejections (CMEs) are solar eruptions that involve large-scale\u0000changes to the magnetic topology of an active region. There exists a range of\u0000models for CME onset which are based on twisted or sheared magnetic field above\u0000a polarity inversion line (PIL). We present observational evidence that\u0000topological changes at PILs, in the photosphere, form a key part of CME onset,\u0000as implied by many models. In particular, we study the onset of 30 CMEs and\u0000investigate topological changes in the photosphere by calculating the magnetic\u0000winding flux, using the texttt{ARTop} code. By matching the times and\u0000locations of winding signatures with CME observations produced by the\u0000texttt{ALMANAC} code, we confirm that these signatures are indeed associated\u0000with CMEs. Therefore, as well as presenting evidence that changes in magnetic\u0000topology at the photosphere are a common signature of CME onset, our approach\u0000also allows for the finding of the source location of a CME within an active\u0000region.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"42 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Discovery of the First Millisecond Pulsar: Personal Recollections","authors":"S. R. Kulkarni","doi":"arxiv-2409.07540","DOIUrl":"https://doi.org/arxiv-2409.07540","url":null,"abstract":"This article provides a first-hand account of the 1982 Arecibo observations\u0000that led to the discovery of PSR B1937+21, the first-known millisecond pulsar.\u0000It is a companion paper to Demorest & Goss (2024) and Readhead (2024).","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The inflated, eccentric warm Jupiter TOI-4914 b orbiting a metal-poor star, and the hot Jupiters TOI-2714 b and TOI-2981 b","authors":"G. Mantovan, T. G. Wilson, L. Borsato, T. Zingales, K. Biazzo, D. Nardiello, L. Malavolta, S. Desidera, F. Marzari, A. Collier Cameron, V. Nascimbeni, F. Z. Majidi, M. Montalto, G. Piotto, K. G. Stassun, J. N. Winn, J. M. Jenkins, L. Mignon, A. Bieryla, D. W. Latham, K. Barkaoui, K. A. Collins, P. Evans, M. M. Fausnaugh, V. Granata, V. Kostov, A. W. Mann, F. J. Pozuelos, D. J. Radford, H. M. Relles, P. Rowden, S. Seager, T. -G. Tan, M. Timmermans, C. N. Watkins","doi":"arxiv-2409.07520","DOIUrl":"https://doi.org/arxiv-2409.07520","url":null,"abstract":"Recent observations of giant planets have revealed unexpected bulk densities.\u0000Hot Jupiters, in particular, appear larger than expected for their masses\u0000compared to planetary evolution models, while warm Jupiters seem denser than\u0000expected. These differences are often attributed to the influence of the\u0000stellar incident flux, but could they also result from different planet\u0000formation processes? Is there a trend linking the planetary density to the\u0000chemical composition of the host star? In this work we present the confirmation\u0000of three giant planets in orbit around solar analogue stars. TOI-2714 b ($P\u0000simeq 2.5$ d, $R_{rm p} simeq 1.22 R_{rm J}$, $M_{rm p} = 0.72 M_{rm J}$)\u0000and TOI-2981 b ($P simeq 3.6$ d, $R_{rm p} simeq 1.2 R_{rm J}$, $M_{rm p}\u0000= 2 M_{rm J}$) are hot Jupiters on nearly circular orbits, while TOI-4914 b\u0000($P simeq 10.6$ d, $R_{rm p} simeq 1.15 R_{rm J}$, $M_{rm p} = 0.72 M_{rm\u0000J}$) is a warm Jupiter with a significant eccentricity ($e = 0.41 pm 0.02$)\u0000that orbits a star more metal-poor ([Fe/H]$~= -0.13$) than most of the stars\u0000known to host giant planets. Our radial velocity (RV) follow-up with the HARPS\u0000spectrograph allows us to detect their Keplerian signals at high significance\u0000(7, 30, and 23$sigma$, respectively) and to place a strong constraint on the\u0000eccentricity of TOI-4914 b (18$sigma$). TOI-4914 b, with its large radius and\u0000low insolation flux ($F_star < 2 times 10^8~{rm erg~s^{-1}~cm^{-2}}$),\u0000appears to be more inflated than what is supported by current theoretical\u0000models for giant planets. Moreover, it does not conform to the previously noted\u0000trend that warm giant planets orbiting metal-poor stars have low\u0000eccentricities. This study thus provides insights into the diverse orbital\u0000characteristics and formation processes of giant exoplanets, in particular the\u0000role of stellar metallicity in the evolution of planetary systems.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"59 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"XUV irradiation of young planetary atmospheres. Results from a joint XMM-Newton and HST observation of HIP67522","authors":"A. Maggio, I. Pillitteri, C. Argiroffi, D. Locci, S. Benatti, G. Micela","doi":"arxiv-2409.07229","DOIUrl":"https://doi.org/arxiv-2409.07229","url":null,"abstract":"The evaporation and the chemistry of the atmospheres of warm and hot planets\u0000are strongly determined by the high-energy irradiation they receive from their\u0000parent stars. This is more crucial among young extra-solar systems, due to the\u0000high activity of stars at early ages. In particular, the EUV part of the\u0000stellar spectra drives significant processes of photo-chemical interaction, but\u0000it is not directly measurable due to strong interstellar absorption and the\u0000lack of sufficiently sensitive instrumentation. An alternative approach is to\u0000derive synthetic spectra from the analysis of FUV and X-ray emission lines,\u0000that allow to estimate the missed flux in the EUV band. We performed joint and\u0000simultaneous spectroscopy of HIP 67522 with XMM-Newton and HST aimed at\u0000reconstructing the full high-energy spectrum of this 17 Myr old solar-type (G0)\u0000star, which is the youngest known transiting multi-planet system at present\u0000time. We performed a time-resolved spectral analysis of the observations,\u0000including quiescent emission and flaring variability. Then, we derived the\u0000Emission Measure Distribution (EMD) vs. temperature of the chromospheric and\u0000coronal plasma from the high-resolution spectra obtained in X-rays with RGS and\u0000in FUV with COS. We derived broad-band X-ray and EUV luminosities from the\u0000synthetic spectrum based on the EMD, that allowed us to test alternative EUV\u0000vs. X-ray scaling laws available in literature. We also employed the total XUV\u0000flux received by the inner planet of the system to estimate its instantaneous\u0000atmospheric mass loss rate. We confirm that HIP 67522 is a very active star\u0000with a hot corona, reaching plasma temperatures above 20 MK even in quiescent\u0000state. Its EUV/X-ray flux ratio falls in between the predictions of the two\u0000scaling laws we have tested, indicating an important spread in the stellar\u0000properties, that requires further investigation.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measuring Sub-Kelvin Variations in Stellar Temperature with High-Resolution Spectroscopy","authors":"Étienne Artigau, Charles Cadieux, Neil J. Cook, René Doyon, Laurie Dauplaise, Luc Arnold, Maya Cadieux, Jean-François Donati, Paul Cristofari, Xavier Delfosse, Pascal Fouqué, Claire Moutou, Pierre Larue, Romain Allart","doi":"arxiv-2409.07260","DOIUrl":"https://doi.org/arxiv-2409.07260","url":null,"abstract":"The detection of stellar variability often relies on the measurement of\u0000selected activity indicators such as coronal emission lines and non-thermal\u0000emissions. On the flip side, the effective stellar temperature is normally seen\u0000as one of the key fundamental parameters (with mass and radius) to\u0000understanding the basic physical nature of a star and its relation with its\u0000environment (e.g., planetary instellation). We present a novel approach for\u0000measuring disk-averaged temperature variations to sub-Kelvin accuracy inspired\u0000by algorithms developed for precision radial velocity. This framework uses the\u0000entire content of the spectrum, not just pre-identified lines, and can be\u0000applied to existing data obtained with high-resolution spectrographs. We\u0000demonstrate the framework by recovering the known rotation periods and\u0000temperature modulation of Barnard star and AU Mic in datasets obtained in the\u0000infrared with SPIRou at CHFT and at optical wavelengths on $epsilon$ Eridani\u0000with HARPS at ESO 3.6-m telescope. We use observations of the transiting hot\u0000Jupiter HD189733,b, obtained with SPIRou, to show that this method can unveil\u0000the minute temperature variation signature expected during the transit event,\u0000an effect analogous to the Rossiter-McLaughlin effect but in temperature space.\u0000This method is a powerful new tool for characterizing stellar activity, and in\u0000particular temperature and magnetic features at the surfaces of cool stars,\u0000affecting both precision radial velocity and transit spectroscopic\u0000observations. We demonstrate the method in the context of high-resolution\u0000spectroscopy but the method could be used at lower resolution.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"57 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Can slow pulsars in Milky Way globular clusters form via partial recycling?","authors":"Kyle Kremer, Claire S. Ye, Craig O. Heinke, Anthony L. Piro, Scott M. Ransom, Frederic A. Rasio","doi":"arxiv-2409.07527","DOIUrl":"https://doi.org/arxiv-2409.07527","url":null,"abstract":"Alongside the population of several hundred radio millisecond pulsars\u0000currently known in Milky Way globular clusters, a subset of six slowly spinning\u0000pulsars (spin periods $0.3-4$,s) are also observed. With inferred magnetic\u0000fields $gtrsim 10^{11},$G and characteristic ages $lesssim10^8,$yr,\u0000explaining the formation of these apparently young pulsars in old stellar\u0000populations poses a major challenge. One popular explanation is that these\u0000objects are not actually young but instead have been partially spun up via\u0000accretion from a binary companion. In this scenario, accretion in a typical\u0000low-mass X-ray binary is interrupted by a dynamical encounter with a\u0000neighboring object in the cluster. Instead of complete spin up to millisecond\u0000spin periods, the accretion is halted prematurely, leaving behind a ``partially\u0000recycled'' neutron star. In this Letter, we use a combination of analytic\u0000arguments motivated by low-mass X-ray binary evolution and $N$-body simulations\u0000to show that this partial-recycling mechanism is not viable. Realistic globular\u0000clusters are not sufficiently dense to interrupt mass transfer on the short\u0000timescales required to achieve such slow spin periods. We argue that collapse\u0000of massive white dwarfs and/or neutron star collisions are more promising ways\u0000to form slow pulsars in old globular clusters.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"72 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stellar energetic particle and cosmic ray effects in exoplanetary atmospheres","authors":"D. Rodgers-Lee","doi":"arxiv-2409.07274","DOIUrl":"https://doi.org/arxiv-2409.07274","url":null,"abstract":"Energetic particles, in the form of stellar energetic particles and cosmic\u0000rays, can lead to disequilibrium chemical effects in exoplanetary atmospheres.\u0000In Earth-like atmospheres, energetic particles can drive the formation of\u0000prebiotic molecules, the building blocks of life. Here instead, I study the\u0000transport of energetic particles through a hydrogen-dominated exoplanet\u0000atmosphere and calculate the resulting ionisation rate of molecular hydrogen\u0000using a Monte Carlo energetic particle transport model. I focus on a GJ436\u0000b-like atmosphere at orbital distances between 0.01-0.2 au which includes the\u0000orbital distance of the exoplanet GJ436 b (0.028 au). I found that stellar\u0000energetic particles lead to high ionisation rates in a GJ436 b-like atmosphere\u0000between 0.01-0.2 au. These results motivate the use of chemical models of gas\u0000giant atmospheres including energetic particle ionisation to ultimately produce\u0000synthetic James Webb Space Telescope (JWST) and Ariel transmission spectra in\u0000the future.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The IXPE View of Neutron Star Low-Mass X-ray Binaries","authors":"Francesco Ursini, Andrea Gnarini, Fiamma Capitanio, Anna Bobrikova, Massimo Cocchi, Alessandro Di Marco, Sergio Fabiani, Ruben Farinelli, Fabio La Monaca, John Rankin, Mary Lynne Saade, Juri Poutanen","doi":"arxiv-2409.07161","DOIUrl":"https://doi.org/arxiv-2409.07161","url":null,"abstract":"Low-mass X-ray binaries hosting weakly magnetized neutron stars (NS-LMXBs)\u0000are among the brightest sources in the X-ray sky. Since 2021, the Imaging X-ray\u0000Polarimetry Explorer (IXPE) has provided new measurements of the X-ray\u0000polarization of these sources. IXPE observations have revealed that most\u0000NS-LMXBs are significantly polarized in the X-rays, providing unprecedented\u0000insight into the geometry of their accretion flow. In this review paper, we\u0000summarize the first results obtained by IXPE on NS-LMXBs, the emerging trends\u0000within each class of sources (atoll/Z), and possible physical interpretations.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"57 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A potential mass-gap black hole in a wide binary with a circular orbit","authors":"Wang Song, Zhao Xinlin, Feng Fabo, Ge Hongwei, Shao Yong, Cui Yingzhen, Gao Shijie, Zhang Lifu, Wang Pei, Li Xue, Bai Zhongrui, Yuan Hailong, Huang Yang, Yuan Haibo, Zhang Zhixiang, Yi Tuan, Xiang Maosheng, Li Zhenwei, Li Tanda, Zhang Junbo, Zhang Meng, Han Henggeng, Fan Dongwei, Li Xiangdong, Chen Xuefei, Liu Zhengwei, Meng Xiangcun, Liu Qingzhong, Zhang Haotong, Gu Wei-Min, Liu Jifeng","doi":"arxiv-2409.06352","DOIUrl":"https://doi.org/arxiv-2409.06352","url":null,"abstract":"Mass distribution of black holes identified through X-ray emission suggests a\u0000paucity of black holes in the mass range of 3 to 5 solar masses. Modified\u0000theories have been devised to explain this mass gap, and it is suggested that\u0000natal kicks during supernova explosion can more easily disrupt binaries with\u0000lower mass black holes. Although recent LIGO observations reveal the existence\u0000of compact remnants within this mass gap, the question of whether low-mass\u0000black holes can exist in binaries remains a matter of debate. Such a system is\u0000expected to be noninteracting without X-ray emission, and can be searched for\u0000using radial velocity and astrometric methods. Here we report Gaia DR3\u00003425577610762832384, a wide binary system including a red giant star and an\u0000unseen object, exhibiting an orbital period of approximately 880 days and\u0000near-zero eccentricity. Through the combination of radial velocity measurements\u0000from LAMOST and astrometric data from Gaia DR2 and DR3 catalogs, we determine a\u0000mass of $3.6^{+0.8}_{-0.5}$ $M_{odot}$ of the unseen component. This places\u0000the unseen companion within the mass gap, strongly suggesting the existence of\u0000binary systems containing low-mass black holes. More notably, the formation of\u0000its surprisingly wide circular orbit challenges current binary evolution and\u0000supernova explosion theories.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Contour Analysis Tool: an interactive tool for background and morphology analysis","authors":"Mark A. Hutchison, Christine M. Koepferl","doi":"arxiv-2409.06421","DOIUrl":"https://doi.org/arxiv-2409.06421","url":null,"abstract":"We introduce the Contour Analysis Tool (CAT), a Python toolkit aimed at\u0000identifying and analyzing structural elements in density maps. CAT employs\u0000various contouring techniques, including the lowest-closed contour (LCC),\u0000linear and logarithmic Otsu thresholding, and average gradient thresholding.\u0000These contours can aid in foreground and background segmentation, providing\u0000natural limits for both, as well as edge detection and structure\u0000identification. Additionally, CAT provides image processing methods such as\u0000smoothing, background removal, and image masking. The toolkit features an\u0000interactive suite of controls designed for Jupyter environments, enabling users\u0000to promptly visualize the effects of different methods and parameters. We\u0000describe, test, and demonstrate the performance of CAT, highlighting its\u0000potential use cases. CAT is publicly available on GitHub, promoting\u0000accessibility and collaboration.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"181 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}