Publications of the Astronomical Society of the Pacific最新文献

{"title":"The Symbiotic X-Ray Binary IGR J16194-2810: A Window on the Future Evolution of Wide Neutron Star Binaries From Gaia","authors":"Pranav Nagarajan, Kareem El-Badry, Casey Lam and Henrique Reggiani","doi":"10.1088/1538-3873/ad5dfd","DOIUrl":"https://doi.org/10.1088/1538-3873/ad5dfd","url":null,"abstract":"We present optical follow-up of IGR J16194-2810, a hard X-ray source discovered by the INTEGRAL mission. The optical counterpart is a ∼500 L⊙ red giant at a distance of 2.1 kpc. We measured 17 radial velocities (RVs) of the giant over a period of 271 days. Fitting these RVs with a Keplerian model, we find an orbital period of Porb = 192.73 ± 0.01 days and a companion mass function f(M2) = 0.365 ± 0.003 M⊙. We detect ellipsoidal variability with the same period in optical light curves from the ASAS-SN survey. Joint fitting of the RVs, light curves, and the broadband spectral energy distribution allows us to robustly constrain the masses of both components. We find a giant mass of and a companion mass of , implying that the companion is a neutron star (NS). We recover a 4.06 hr period in the system’s TESS light curve, which we tentatively associate with the NS spin period. The giant does not yet fill its Roche lobe, suggesting that current mass transfer is primarily via winds. Modules for Experiments in Stellar Astrophysics evolutionary models predict that the giant will overflow its Roche lobe in 5–10 Myr, eventually forming a recycled pulsar + white dwarf binary with a ∼900 days period. IGR J16194-2810 provides a window on the future evolution of wide NS + main sequence binaries recently discovered via Gaia astrometry. As with those systems, the binary’s formation history is uncertain. Before the formation of the NS, it likely survived a common envelope episode with a donor-to-accretor mass ratio ≳10 and emerged in a wide orbit. The NS likely formed with a weak kick (vkick ≲ 50 km s−1), as stronger kicks would have disrupted the orbit.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":"38 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141753996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"No Longer Impossible: The Self-lensing Binary KIC 8145411 is a Triple","authors":"Natsuko Yamaguchi, Kareem El-Badry, David R. Ciardi, David W. Latham, Kento Masuda, Allyson Bieryla, Catherine A. Clark and Samuel S. Condon","doi":"10.1088/1538-3873/ad5ebd","DOIUrl":"https://doi.org/10.1088/1538-3873/ad5ebd","url":null,"abstract":"Five self-lensing binaries (SLBs) have been discovered with data from the Kepler mission. One of these systems is KIC 8145411, which was reported to host an extremely low mass (ELM; 0.2 M⊙) white dwarf (WD) in a 456 days orbit with a solar-type companion. The system has been dubbed \"impossible,\" because evolutionary models predict that ∼0.2 M⊙ WDs should only be found in tight orbits (Porb ≲ days). In this work, we show that KIC 8145411 is in fact a hierarchical triple system: it contains a WD orbiting a solar-type star, with another solar-type star ∼700 au away. The wide companion was unresolved in the Kepler light curves, was just barely resolved in Gaia DR3, and is resolved beyond any doubt by high-resolution imaging. We show that the presence of this tertiary confounded previous mass measurements of the WD for two reason: it dilutes the amplitude of the self-lensing pulses, and it reduces the apparent radial velocity (RV) variability amplitude of the WD's companion due to line blending. By jointly fitting the system's light curves, RVs, and multi-band photometry using a model with two luminous stars, we obtain a revised WD mass of (0.53 ± 0.01)M⊙. Both luminous stars are near the end of their main-sequence evolution. The WD is thus not an ELM WD, and the system does not suffer the previously proposed challenges to its formation history. Similar to the other SLBs and the population of astrometric WD binaries recently identified from Gaia data, KIC 8145411 has parameters in tension with standard expectations for formation through both stable and unstable mass transfer (MT). The system's properties are likely best understood as a result of unstable MT from an AGB star donor.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":"61 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141737744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"AstroDLLC: Efficiently Reducing Storage and Transmission Costs for Massive Solar Observation Data via Deep Learning-based Lossless Compression","authors":"Xiaoying Liu, Yingbo Liu, Lei Yang, Shichao Wu, Rong Jiang and Yongyuan Xiang","doi":"10.1088/1538-3873/ad5b8a","DOIUrl":"https://doi.org/10.1088/1538-3873/ad5b8a","url":null,"abstract":"Effective data compression technology is essential for addressing data storage and transmission needs, especially given the escalating volume and complexity of data generated by contemporary astronomy. In this study, we propose utilizing deep learning-based lossless compression techniques to improve compression efficiency. We begin with a qualitative and quantitative analysis of the temporal and spatial redundancy in solar observation data. Based on this analysis, we introduce a novel deep learning-based framework called AstroDLLC for the lossless compression of astronomical solar images. AstroDLLC first segments high-resolution images into blocks to ensure that deep learning model training does not rely on high-computation power devices. It then addresses the non-normality of the partitioned data through simple reversible computational methods. Finally, it utilizes Bit-swap to train deep learning models that capture redundant features across multiple image frames, thereby enhancing compression efficiency. Comprehensive evaluations using data from the New Vacuum Solar Telescope reveal that AstroDLLC achieves a maximum compression ratio of 3.00 per image, surpassing Gzip, RICE, and other lossless technologies. The performance of AstroDLLC underscores its potential to address data compression challenges in astronomy.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":"117 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141611058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Astrometry as a Tool for Discovering and Weighing Faint Companions to Nearby Stars","authors":"Timothy D. Brandt","doi":"10.1088/1538-3873/ad59c5","DOIUrl":"https://doi.org/10.1088/1538-3873/ad59c5","url":null,"abstract":"This tutorial covers the use of absolute astrometry, in particular from the combination of the Hipparcos and Gaia missions, to identify faint companions to nearby stars and to measure the masses and orbits of those companions. Absolute astrometry has been used with increasing success to discover new planets and brown dwarfs and to measure masses and orbits for systems with periods as long as centuries. This tutorial summarizes the nature of the underlying astrometric data, the approach typically used to fit orbits, and the assumptions about that data implicit throughout the process. It attempts to provide intuition for the sensitivity of astrometry as a function of stellar and companion properties and how the available constraints depend on the character and quantity of data available. This tutorial is written for someone with some background in astronomy but with no more than a minimal acquaintance with astrometry or orbit fitting.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":"21 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141588022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Pushing the Limits of the Cosmic Origin Spectrograph (COS) with an Optimized Background Correction","authors":"Svea Hernandez, Andrei Igoshev, Jo Taylor, David Sahnow, Logan Jones","doi":"10.1088/1538-3873/ad57f6","DOIUrl":"https://doi.org/10.1088/1538-3873/ad57f6","url":null,"abstract":"Observations utilizing the ultraviolet capabilities of the Cosmic Origin Spectrograph (COS) onboard the Hubble Space Telescope are of unique value to the astronomy community. Spectroscopy down to 900 Å with COS has enabled new science areas. However, contrary to the situation at longer wavelengths, these observations are limited by detector background noise. The background correction currently applied by the standard calibration pipeline (<monospace>CalCOS</monospace>) is not optimized for faint targets, limiting the scientific value of low signal-to-noise ratio (S/N) observations. In this work we investigate a possible dependence of the variations of the dark rate in both segments of the COS far-ultraviolet detector on time, detector high voltage (HV), and solar activity. Through our analysis we identified a number of detector states (on a configuration basis, e.g., HV and segment) characterizing the spatial distribution of dark counts, and created superdarks to be used in an optimized two-dimensional (2D) background correction. We have developed and tested Another COS Dark Correction (<monospace>ACDC</monospace>), a dedicated pipeline to perform a 2D background correction based on statistical methods, producing background-corrected and flux-calibrated spectra. While our testing of ACDC showed an average improvement in S/N values of ∼10%, in a few cases the improvements in S/N reached 60% across the whole wavelength range of individual segments.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":"88 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141577192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Enhancing Exoplanet Ephemerides by Leveraging Professional and Citizen Science Data: A Test Case with WASP-77 A b","authors":"Federico R. Noguer, Suber Corley, Kyle A. Pearson, Robert T. Zellem, Molly N. Simon, Jennifer A. Burt, Isabela Huckabee, Prune C. August, Megan Weiner Mansfield, Paul A. Dalba, Peter C. B. Smith, Timothy Banks, Ira Bell, Dominique Daniel, Lindsay Dawson, Jesús De Mula, Marc Deldem, Dimitrios Deligeorgopoulos, Romina P. Di Sisto, Roger Dymock, Phil Evans, Giulio Follero, Martin J. F. Fowler, Eduardo Fernández-Lajús, Alex Hamrick, Nicoletta Iannascoli, Andre O. Kovacs, Denis Henrique Kulh, Claudio Lopresti, Antonio Marino, Bryan E. Martin, Paolo Arcangelo Matassa, Tasso Augusto Napoleão, Alessandro Nastasi, Anthony Norris, Alessandro Odasso, Nikolaos I. Paschalis, Pavel Pintr, Jake Postiglione, Justus Randolph, François Regembal, Lionel Rousselot, Sergio José Gonçalves da Silva, Andrew Smith and Andrea Tomacelli","doi":"10.1088/1538-3873/ad57f5","DOIUrl":"https://doi.org/10.1088/1538-3873/ad57f5","url":null,"abstract":"We present an updated ephemeris, and physical parameters, for the exoplanet WASP-77 A b. In this effort, we combine 64 ground- and space-based transit observations, 6 space-based eclipse observations, and 32 radial velocity observations to produce this target's most precise orbital solution to date aiding in the planning of James Webb Space Telescope and Ariel observations and atmospheric studies. We report a new orbital period of 1.360029395 ± 5.7 × 10−8 days, a new mid-transit time of 2459957.337860 ± 4.3 × 10−5 Barycentric Julian Date in the Barycentric Dynamical Timescale (BJDTDB) and a new mid-eclipse time of 2459956.658192 ± 6.7 × 10−5 BJDTDB. Furthermore, the methods presented in this study reduce the uncertainties in the planet's mass 1.6654 ± 4.5 × 10−3MJup and orbital period 1.360029395 ± 5.7 × 10−8 days by factors of 15.1 and 10.9, respectively. Through a joint fit analysis comparison of transit data taken by space-based and citizen science-led initiatives, our study demonstrates the power of including data collected by citizen scientists compared to a fit of the space-based data alone. Additionally, by including a vast array of citizen science data from ExoClock, Exoplanet Transit Database, and Exoplanet Watch, we can increase our observational baseline and thus acquire better constraints on the forward propagation of our ephemeris than what is achievable with Transiting Exoplanet Survey Satellite data alone.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":"48 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141551446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"A Suite of Classical Cepheids Tied to the Binary Cluster Berkeley 58 and NGC 7790","authors":"Daniel Majaess and David G. Turner","doi":"10.1088/1538-3873/ad59c6","DOIUrl":"https://doi.org/10.1088/1538-3873/ad59c6","url":null,"abstract":"The classical Cepheids CE Cas A, CE Cas B, CF Cas, and CG Cas are likely members of the binary open cluster comprising NGC 7790 and Berkeley 58. The clusters are of comparable age and in close proximity, as deduced from differentially dereddened UuBPBVGRP photometry, and Cepheid period-age relations. Gaia DR3 astrometric and spectroscopic solutions for the clusters are likewise consistent. Conversely, the seemingly adjacent open cluster NGC 7788 is substantially younger and nearer.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":"71 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141551447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Identification of Radio Frequency Interference Using Multi-scale TransUNet","authors":"Xuan Zhang, Bo Liang, Longfei Hao, Song Feng, Shoulin Wei, Wei Dai and Yihang Dao","doi":"10.1088/1538-3873/ad54ef","DOIUrl":"https://doi.org/10.1088/1538-3873/ad54ef","url":null,"abstract":"Radio observation is a method for conducting astronomical observations using radio waves. A common challenge in radio observations is Radio Frequency Interference (RFI), which refers to the unintentional or intentional interference of radio signals from other wireless sources within the radio frequency band. Such interference contaminates the astronomical signals received by radio telescopes, significantly affecting time–frequency domain astronomical observations and research. Consequently, identifying RFI is crucial. In this paper, we employ a deep learning approach to detect RFI present in observation data and propose an improved network structure based on TransUNet. This network leverages the principles of a multi-scale convolutional attention mechanism. It introduces an auxiliary branch to extract high-dimensional image information and an enhanced coordinate attention mechanism for feature map extraction, enabling more comprehensive and accurate identification of RFI in time–frequency images. We introduce a novel architecture named the Multi-Scale TransUNet Network, abbreviated as MS-TransUNet. We utilized observation data from the 40 m radio telescope at the Yunnan Observatory as a data set for training, validating, and testing the network. Compared with previous deep learning networks (U-Net, RFI-Net, R-Net, DSC, EMSCA-UNet), the recall rate and f2 score have been significantly improved. Specifically, the recall rate is improved by at least 2.99%, and the f2 score is improved by at least 2.46%. Experiments demonstrate that this network is exceptional in identifying RFI more comprehensively while ensuring high precision.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":"3 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"ROME/REA: Three-year, Tri-color Timeseries Photometry of the Galactic Bulge","authors":"R. A. Street, E. Bachelet, Y. Tsapras, M. P. G. Hundertmark, V. Bozza, D. M. Bramich, A. Cassan, M. Dominik, R. Figuera Jaimes, K. Horne, S. Mao, A. Saha, J. Wambsganss, Weicheng Zang","doi":"10.1088/1538-3873/ad4e69","DOIUrl":"https://doi.org/10.1088/1538-3873/ad4e69","url":null,"abstract":"The Robotic Observations of Microlensing Events/Reactive Event Assessment Survey was a Key Project at Las Cumbres Observatory (hereafter LCO) which continuously monitored 20 selected fields (3.76 sq.deg) in the Galactic Bulge throughout their seasonal visibility window over a three-year period, between 2017 March and 2020 March. Observations were made in three optical passbands (SDSS&lt;inline-formula&gt;\u0000&lt;tex-math&gt;\u0000&lt;?CDATA $-g^{prime} $?&gt;\u0000&lt;/tex-math&gt;\u0000&lt;mml:math overflow=\"scroll\"&gt;&lt;mml:mo&gt;−&lt;/mml:mo&gt;&lt;mml:mi&gt;g&lt;/mml:mi&gt;&lt;mml:mo accent=\"false\"&gt;′&lt;/mml:mo&gt;&lt;/mml:math&gt;\u0000&lt;inline-graphic xlink:href=\"paspad4e69ieqn1.gif\" xlink:type=\"simple\"&gt;&lt;/inline-graphic&gt;\u0000&lt;/inline-formula&gt;, &lt;inline-formula&gt;\u0000&lt;tex-math&gt;\u0000&lt;?CDATA $-r^{prime} $?&gt;\u0000&lt;/tex-math&gt;\u0000&lt;mml:math overflow=\"scroll\"&gt;&lt;mml:mo&gt;−&lt;/mml:mo&gt;&lt;mml:mi&gt;r&lt;/mml:mi&gt;&lt;mml:mo accent=\"false\"&gt;′&lt;/mml:mo&gt;&lt;/mml:math&gt;\u0000&lt;inline-graphic xlink:href=\"paspad4e69ieqn2.gif\" xlink:type=\"simple\"&gt;&lt;/inline-graphic&gt;\u0000&lt;/inline-formula&gt;, &lt;inline-formula&gt;\u0000&lt;tex-math&gt;\u0000&lt;?CDATA $-i^{prime} $?&gt;\u0000&lt;/tex-math&gt;\u0000&lt;mml:math overflow=\"scroll\"&gt;&lt;mml:mo&gt;−&lt;/mml:mo&gt;&lt;mml:mi&gt;i&lt;/mml:mi&gt;&lt;mml:mo accent=\"false\"&gt;′&lt;/mml:mo&gt;&lt;/mml:math&gt;\u0000&lt;inline-graphic xlink:href=\"paspad4e69ieqn3.gif\" xlink:type=\"simple\"&gt;&lt;/inline-graphic&gt;\u0000&lt;/inline-formula&gt;), and LCO’s multi-site telescope network enabled the survey to achieve a typical cadence of ∼10 hr in &lt;inline-formula&gt;\u0000&lt;tex-math&gt;\u0000&lt;?CDATA $i^{prime} $?&gt;\u0000&lt;/tex-math&gt;\u0000&lt;mml:math overflow=\"scroll\"&gt;&lt;mml:mi&gt;i&lt;/mml:mi&gt;&lt;mml:mo accent=\"false\"&gt;′&lt;/mml:mo&gt;&lt;/mml:math&gt;\u0000&lt;inline-graphic xlink:href=\"paspad4e69ieqn4.gif\" xlink:type=\"simple\"&gt;&lt;/inline-graphic&gt;\u0000&lt;/inline-formula&gt; and ∼15 hr in &lt;inline-formula&gt;\u0000&lt;tex-math&gt;\u0000&lt;?CDATA $g^{prime} $?&gt;\u0000&lt;/tex-math&gt;\u0000&lt;mml:math overflow=\"scroll\"&gt;&lt;mml:mi&gt;g&lt;/mml:mi&gt;&lt;mml:mo accent=\"false\"&gt;′&lt;/mml:mo&gt;&lt;/mml:math&gt;\u0000&lt;inline-graphic xlink:href=\"paspad4e69ieqn5.gif\" xlink:type=\"simple\"&gt;&lt;/inline-graphic&gt;\u0000&lt;/inline-formula&gt; and &lt;inline-formula&gt;\u0000&lt;tex-math&gt;\u0000&lt;?CDATA $r^{prime} $?&gt;\u0000&lt;/tex-math&gt;\u0000&lt;mml:math overflow=\"scroll\"&gt;&lt;mml:mi&gt;r&lt;/mml:mi&gt;&lt;mml:mo accent=\"false\"&gt;′&lt;/mml:mo&gt;&lt;/mml:math&gt;\u0000&lt;inline-graphic xlink:href=\"paspad4e69ieqn6.gif\" xlink:type=\"simple\"&gt;&lt;/inline-graphic&gt;\u0000&lt;/inline-formula&gt;. In addition, intervals of higher cadence (&lt;1 hr) data were obtained during monitoring of key microlensing events within the fields. This paper describes the Difference Image Analysis data reduction pipeline developed to process these data, and the process for combining the photometry from LCO’s three observing sites in the Southern Hemisphere. The full timeseries photometry for all ∼8 million stars, down to a limiting magnitude of &lt;italic toggle=\"yes\"&gt;i&lt;/italic&gt; ∼ 18 mag is provided in the data release accompanying this paper, and samples of the data are presented for exemplar microlensing events, illustrating how the tri-band data are used to derive constraints on the microlensing source star parameters, a necessary step in determining the physical properties of the lensing object. The timeseries data also enables a wealth of additional science, for example in cha","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":"76 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"A Quick Guide to Nearby Young Associations","authors":"Jonathan Gagné","doi":"10.1088/1538-3873/ad4e6a","DOIUrl":"https://doi.org/10.1088/1538-3873/ad4e6a","url":null,"abstract":"Nearby associations of stars which are coeval are important benchmark laboratories because they provide robust measurements of stellar ages. The study of such coeval groups makes it possible to better understand star formation by studying the initial mass function, the binary fraction or the circumstellar disks of stars, to determine how the initially dense populations of young stars gradually disperse to form the field population, and to shed light on how the properties of stars, exoplanets and substellar objects evolve with distinct snapshots along their lifetime. The advent of large-scale missions such as Gaia is reshaping our understanding or stellar kinematics in the Solar neighborhood and beyond, and offers the opportunity to detect a large number of loose, coeval stellar associations for the first time, which evaded prior detection because of their low density or the faintness of their members. In parallel, advances in detection and characterization of exoplanets and substellar objects are starting to unveil the detailed properties of extrasolar atmospheres, as well as population-level distributions in fundamental exoplanet properties such as radii, masses, and orbital parameters. Accurate ages are still sparsely available to interpret the evolution of both exoplanets and substellar objects, and both fields are now ripe for detailed age investigations because we are starting to uncover ever-closer low-density associations that previously escaped detection, as well as exoplanets and ever lower-mass members of more distant open clusters and star-forming regions. In this paper, we review some recent advances in the identification and characterization of nearby associations, the methods by which stellar ages are measured, and some of the direct applications of the study of young associations such as the emergent field of isolated planetary-mass objects.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":"85 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}