arXiv - PHYS - Solar and Stellar Astrophysics最新文献

{"title":"Multi-wavelength spectroscopic analysis of the ULX Holmberg II","authors":"S. Reyero Serantes, L. Oskinova, W. -R. Hamann, V. M. Gómez-González, H. Todt, D. Pauli, R. Soria, D. R. Gies, J. M. Torrejón, T. Bulik, V. Ramachandran, A. A. C. Sander, E. Bozzo, J. Poutanen","doi":"arxiv-2409.12133","DOIUrl":"https://doi.org/arxiv-2409.12133","url":null,"abstract":"Ultra-luminous X-ray sources (ULXs) are high-mass X-ray binaries with an\u0000X-ray luminosity above $10^{39}$ erg s$^{-1}$. These ULXs can be powered by\u0000black holes that are more massive than $20M_odot$, accreting in a standard\u0000regime, or lighter compact objects accreting supercritically. There are only a\u0000few ULXs with known optical or UV counterparts, and their nature is debated.\u0000Determining whether optical/UV radiation is produced by the donor star or by\u0000the accretion disc is crucial for understanding ULX physics and testing massive\u0000binary evolution. We conduct, for the first time, a fully consistent\u0000multi-wavelength spectral analysis of a ULX and its circumstellar nebula. We\u0000aim to establish the donor star type and test the presence of strong disc winds\u0000in the prototypical ULX Holmberg II X-1 (Ho II X-1). We intent to obtain a\u0000realistic spectral energy distribution of the ionising source, which is needed\u0000for robust nebula analysis. We acquired new UV spectra of Ho II X-1 with the\u0000HST and complemented them with archival optical and X-ray data. We explored the\u0000spectral energy distribution of the source and analysed the spectra using the\u0000stellar atmosphere code PoWR and the photoionisation code Cloudy. Our analysis\u0000of the X-ray, UV, and optical spectra of Ho II X-1 and its nebula consistently\u0000explains the observations. We do not find traces of disc wind signatures in the\u0000UV and the optical, rejecting previous claims of the ULX being a supercritical\u0000accretor. The optical/UV counterpart of HoII X-1 is explained by a B-type\u0000supergiant donor star. Thus, the observations are fully compatible with Ho II\u0000X-1 being a close binary consisting of an $gtrsim 66,M_odot$ black hole\u0000accreting matter from an $simeq 22 M_odot$ B-supergiant companion. Also, we\u0000propose a possible evolution scenario for the system, suggesting that Ho II X-1\u0000is a potential gravitational wave source progenitor.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257934","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":"Characterization of blue and yellow straggler stars of Berkeley 39 using Swift/UVOT","authors":"Komal Chand, Khushboo Rao, Kaushar Vaidya, Anju Panthi","doi":"arxiv-2409.12062","DOIUrl":"https://doi.org/arxiv-2409.12062","url":null,"abstract":"We characterize blue straggler stars (BSS) and yellow straggler stars (YSS)\u0000of an open cluster (OC) Berkeley 39 using multi-wavelength observations\u0000including Swift/UVOT. Our analysis also makes use of ultraviolet (UV) data from\u0000GALEX, optical data from Gaia DR3 and Pan-STARRS, and infrared data from 2MASS,\u0000Spitzer/IRAC, and WISE. Berkeley 39 is a ~6 Gyr old Galactic OC located at a\u0000distance of ~4200 pc. We identify 729 sources as cluster members utilizing a\u0000machine learning algorithm, ML-MOC, on Gaia DR3 data. Of these, 17 sources are\u0000classified as BSS candidates and four as YSS candidates. We construct\u0000multi-wavelength spectral energy distributions (SEDs) of 16 BSS and 2 YSS\u0000candidates, within the Swift/UVOT field, to analyze their properties. Out of\u0000these, 8 BSS candidates and both the YSS candidates are successfully fitted\u0000with single-component SEDs. Five BSS candidates show marginal excess in the\u0000near-UV (fractional residual < 0.3 in all but one UVOT filter), whereas three\u0000BSS candidates show moderate to significant excess in the near-UV (fractional\u0000residual > 0.3 in at least two UVOT filters). We present the properties of the\u0000BSS and YSS candidates, estimated based on the SED fits.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257927","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":"Denoising medium resolution stellar spectra with neural networks","authors":"Balázs Pál, László Dobos","doi":"arxiv-2409.11625","DOIUrl":"https://doi.org/arxiv-2409.11625","url":null,"abstract":"We trained denoiser autoencoding neural networks on medium resolution\u0000simulated optical spectra of late-type stars to demonstrate that the\u0000reconstruction of the original flux is possible at a typical relative error of\u0000a fraction of a percent down to a typical signal-to-noise ratio of 10 per\u0000pixel. We show that relatively simple networks are capable of learning the\u0000characteristics of stellar spectra while still flexible enough to adapt to\u0000different values of extinction and fluxing imperfections that modifies the\u0000overall shape of the continuum, as well as to different values of Doppler\u0000shift. Denoised spectra can be used to find initial values for traditional\u0000stellar template fitting algorithms and - since evaluation of pre-trained\u0000neural networks is significantly faster than traditional template fitting -\u0000denoiser networks can be useful when a fast analysis of the noisy spectrum is\u0000necessary, for example during observations, between individual exposures.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257933","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":"Exoplanet accretion monitoring spectroscopic survey (ENTROPY) I. Evidence for magnetospheric accretion in the young isolated planetary-mass object 2MASS J11151597+1937266","authors":"Gayathri Viswanath, Simon C. Ringqvist, Dorian Demars, Markus Janson, Mickaël Bonnefoy, Yuhiko Aoyama, Gabriel-Dominique Marleau, Catherine Dougados, Judit Szulágyi, Thanawuth Thanathibodee","doi":"arxiv-2409.12187","DOIUrl":"https://doi.org/arxiv-2409.12187","url":null,"abstract":"Accretion among planets is a poorly understood phenomenon, due to lack of\u0000both observational and theoretical studies. Detection of emission lines from\u0000accreting gas giants facilitate detailed investigations into this process. This\u0000work presents a detailed analysis of Balmer lines from one of the few known\u0000young, planetary-mass objects with observed emission, the isolated L2 dwarf\u00002MASS J11151597+1937266 with a mass 7-21 Mj and age 5-45 Myr, located at 45+-2\u0000pc. We obtained the first high-resolution (R~50,000) spectrum of the target\u0000with VLT/UVES, a spectrograph in the near-UV to visible wavelengths (3200-6800\u0000AA). We report resolved H3-H6 and He I (5875.6 AA) emission in the spectrum.\u0000Based on the asymmetric line profiles of H3 and H4, 10% width of H3 (199+-1\u0000km/s), tentative He I 6678 AA emission and indications of a disk from MIR\u0000excess, we confirm ongoing accretion at this object. Using the Gaia update of\u0000the parallax, we revise its temperature to 1816+-63 K and radius to 1.5+-0.1\u0000Rj. Analysis of observed H I profiles using 1D planet-surface shock model\u0000implies a pre-shock gas velocity of v0=120(+80,-40) km/s and a pre-shock\u0000density of log(n0/cm^-3)=14(+0,-5). Pre-shock velocity points to a mass of\u00006(+8,-4) Mj for the target. Combining the H I line luminosities and planetary\u0000Lline-Lacc scaling relations, we derive a mass accretion rate of\u00001.4(+2.8,-0.9)x10^-8 Mj/yr.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257935","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":"SWEET-Cat: A view on the planetary mass-radius relation","authors":"S. G. Sousa, V. Adibekyan, E. Delgado-Mena, N. C. Santos, B. Rojas-Ayala, S. C. Barros, O. D. S. Demangeon, S. Hoyer, G. Israelian, A. Mortier, B. M. T. Soares, M. Tsantaki","doi":"arxiv-2409.11965","DOIUrl":"https://doi.org/arxiv-2409.11965","url":null,"abstract":"SWEET-Cat (Stars With ExoplanETs Catalogue) was originally introduced in\u00002013, and since then, the number of confirmed exoplanets has increased\u0000significantly. A crucial step for a comprehensive understanding of these new\u0000worlds is the precise and homogeneous characterization of their host stars. We\u0000used a large number of high-resolution spectra to continue the addition of new\u0000stellar parameters for planet-host stars in SWEET-Cat following the new\u0000detection of exoplanets listed both at the Extrasolar Planets Encyclopedia and\u0000at the NASA exoplanet archive. We obtained high-resolution spectra for a\u0000significant number of these planet-host stars, either observed by our team or\u0000collected through public archives. For FGK stars, the spectroscopic stellar\u0000parameters were derived for the spectra following the same homogeneous process\u0000using ARES+MOOG as for the previous SWEET-Cat releases. The stellar properties\u0000are combined with the planet properties to study possible correlations that\u0000could shed more light into the star-planet connection studies. We increase the\u0000number of stars with homogeneous parameters by 232 ($sim$ 25% - from 959 to\u00001191). We then focus on the exoplanets with both mass and radius determined to\u0000review the mass-radius relation where we find consistent results with the ones\u0000previously reported in the literature. For the massive planets we also revisit\u0000the radius anomaly where we confirm a metallicity correlation for the radius\u0000anomaly already hinted in previous results.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"208 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142269172","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":"MINDS. JWST-MIRI Observations of a Spatially Resolved Atomic Jet and Polychromatic Molecular Wind Toward SY Cha","authors":"Kamber R. Schwarz, Matthias Samland, Göran Olofsson, Thomas Henning, Andrew Sellek, Manuel Güdel, Benoît Tabone, Inga Kamp, Pierre-Olivier Lagage, Ewine F. van Dishoeck, Alessio Caratti o Garatti, Adrian M. Glauser, Tom P. Ray, Aditya M. Arabhavi, Valentin Christiaens, Riccardo Franceschi, Danny Gasman, Sierra L. Grant, Jayatee Kanwar, Till Kaeufer, Nicolas T. Kurtovic, Giulia Perotti, Milou Temmink, Marissa Vlasblom","doi":"arxiv-2409.11176","DOIUrl":"https://doi.org/arxiv-2409.11176","url":null,"abstract":"The removal of angular momentum from protostellar systems drives accretion\u0000onto the central star and may drive the dispersal of the protoplanetary disk.\u0000Winds and jets can contribute to removing angular momentum from the disk,\u0000though the dominant process remain unclear. To date, observational studies of\u0000resolved disk winds have mostly targeted highly inclined disks. We report the\u0000detection of extended H2 and [Ne II] emission toward the young stellar object\u0000SY Cha with the JWST Mid-InfraRed Instrument Medium Resolution Spectrometer\u0000(MIRI-MRS). This is one of the first polychromatic detections of extended H2\u0000toward a moderately inclined, i=51.1 degrees, Class II source. We measure the\u0000semi-opening angle of the H2 emission as well as build a rotation diagram to\u0000determine the H2 excitation temperature and abundance. We find a wide\u0000semi-opening angle, high temperature, and low column density for the H2\u0000emission, all of which are characteristic of a disk wind. These observations\u0000demonstrate MIRI-MRS's utility in expanding studies of resolved disk winds\u0000beyond edge-on sources.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"55 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257977","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":"Instability and warping in vertically oscillating accretion discs","authors":"Loren E. Held, Gordon I. Ogilvie","doi":"arxiv-2409.11490","DOIUrl":"https://doi.org/arxiv-2409.11490","url":null,"abstract":"Many accretion discs have been found to be distorted: either warped due a\u0000misalignment in the system, or non-circular as a result of orbital eccentricity\u0000or tidal deformation by a binary companion. Warped, eccentric, and tidally\u0000distorted discs are not in vertical hydrostatic equilibrium, and thus exhibit\u0000vertical oscillations in the direction perpendicular to the disc, a phenomenon\u0000that is absent in circular and flat discs. In extreme cases, this vertical\u0000motion is manifested as a vertical `bouncing' of the gas, potentially leading\u0000to shocks and heating, as observed in recent global numerical simulations. In\u0000this paper we isolate the mechanics of vertical disc oscillations by means of\u0000quasi-2D and fully 3D hydrodynamic local (shearing-box) models. To determine\u0000the numerical and physical dissipation mechanisms at work during an oscillation\u0000we start by investigating unforced oscillations, examining the effect of\u0000initial oscillation amplitude, as well as resolution, boundary conditions, and\u0000vertical box size on the dissipation and energetics of the oscillations. We\u0000then drive the oscillations by introducing a time-dependent gravitational\u0000potential. A key result is that even a purely vertically oscillating disc is\u0000(parametrically) unstable to developing inertial waves, as we confirm through a\u0000linear stability analysis. The most important of these has the character of a\u0000bending wave, whose radial wavelength depends on the frequency of the vertical\u0000oscillation. The nonlinear phase of the instability exhibits shocks, which\u0000dampen the oscillations, although energy can also flow from the bending wave\u0000back to the vertical oscillation.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257932","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":"Powerful flares and magneto-elastic oscillations of magnetars","authors":"D. G. YakovlevIoffe Institute","doi":"arxiv-2409.11178","DOIUrl":"https://doi.org/arxiv-2409.11178","url":null,"abstract":"Magnetars are neutron stars with superstrong magnetic fields which can exceed\u00001e15 G. Some magnetars (the so-called soft gamma-repeaters) demonstrate\u0000occasionally very powerful processes of energy release, which result in\u0000exceptionally strong flares of electromagnetic radiation. It is believed that\u0000these flares are associated with the presence of superstrong magnetic fields.\u0000Despite many hypotheses, the mechanism of these flares remains a mystery. In\u0000afterglows of the flares, one has often observed quasi-periodic oscillations\u0000(QPOs) of magnetar emission. They are interpreted as stellar vibrations,\u0000excited by the flares, which are useful for exploring the nature of magnetar\u0000activity. The incompleteness of theories employed to interpret magnetar QPOs is\u0000discussed.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257980","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":"Spot Modeling through Multiband Photometry Analysis of V1298 Tau","authors":"Alfredo Biagini, Antonino Petralia, Claudia Di Maio, Lorenzo Betti, Emanuele Pace, Giuseppina Micela","doi":"arxiv-2409.11034","DOIUrl":"https://doi.org/arxiv-2409.11034","url":null,"abstract":"Context. Stellar activity consists of different phenomena, mainly spots and\u0000faculae, and it is one of the main sources of noise in exoplanetary\u0000observations because it affects both spectroscopic and photometric\u0000observations. If we want to study young active planetary systems we need to\u0000model the activity of the host stars in order to remove astrophysical noise\u0000from our observational data. Aims. We modelled the contribution of stellar\u0000spots in photometric observations. Through the use of multiband photometry, we\u0000aim to extract the geometric properties of the spots and constrain their\u0000temperature. Methods. We analyzed multiband photometric observations acquired\u0000with the 80 cm Marcon telescope of the Osservatorio Polifunzionale del Chianti\u0000of V1298 Tau, assuming that the photometric modulation observed in different\u0000bands should be due to cold spots. Results. We constrained the effective\u0000temperature of the active regions present on the surface of V1298 Tau, which is\u0000composed by the contemporary presence of spots and faculae. We tested our\u0000hypothesis on solar data, verifying that we measure the size of the dominant\u0000active region and its averaged effective temperature.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257978","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":"Linking Transients to their Host Galaxies: II. A Comparison of Host Galaxy Properties and Rate Dependencies across Supernova Types","authors":"Yu-Jing Qin, Ann Zabludoff","doi":"arxiv-2409.11461","DOIUrl":"https://doi.org/arxiv-2409.11461","url":null,"abstract":"We use the latest dataset of supernova (SN) host galaxies to investigate how\u0000the host properties -- stellar mass, star formation rate, metallicity, absolute\u0000magnitude, and colour -- differ across SN types, with redshift-driven selection\u0000effects controlled. SN Ib and Ic host galaxies, on average, are more massive,\u0000metal-rich, and redder than SN II hosts. For subtypes, SN Ibn and Ic-BL have\u0000bluer hosts than their normal SN Ib and Ic siblings; SN IIb has consistent host\u0000properties with SN Ib, while hosts of SN IIn are more metal-rich than those of\u0000SN II. Hydrogen-deficient superluminous supernovae feature bluer and lower\u0000luminosity hosts than most subtypes of core-collapse supernova (CC SN).\u0000Assuming simple proportionality of CC SN rates and host star formation rates\u0000(SFRs) does not recover the observed mean host properties; either a population\u0000of long-lived progenitors or a metallicity-dependent SN production efficiency\u0000better reproduces the observed host properties. Assuming the latter case, the\u0000rates of SN II are insensitive to host metallicity, but the rates of SN Ib and\u0000Ic are substantially enhanced in metal-rich hosts by a factor of ~10 per dex\u0000increase in metallicity. Hosts of SN Ia are diverse in their observed\u0000properties; subtypes including SN Ia-91T, Ia-02cx, and Ia-CSM prefer\u0000star-forming hosts, while subtypes like SN Ia-91bg and Ca-rich prefer quiescent\u0000hosts. The rates of SN Ia-91T, Ia-02cx, and Ia-CSM are closely dependent on, or\u0000even proportional to, their host SFRs, indicating relatively short-lived\u0000progenitors. Conversely, the rates of SN Ia-91bg and Ca-rich transients are\u0000proportional to the total stellar mass, favoring long-lived progenitors.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142269173","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}