Standing on the shoulders of Dwarfs: the $Kepler$ asteroseismic LEGACY sample I - oscillation mode parameters
Mikkel N. Lund, Víctor Silva Aguirre, Guy R. Davies, William J. Chaplin, Jørgen Christensen-Dalsgaard, Günter Houdek, Timothy R. White, Timothy R. Bedding, Warr… 展开作者
Mikkel N. Lund, Víctor Silva Aguirre, Guy R. Davies, William J. Chaplin, Jørgen Christensen-Dalsgaard, Günter Houdek, Timothy R. White, Timothy R. Bedding, Warrick H. Ball, Daniel Huber, H. M. Antia, Yveline Lebreton, David W. Latham, Rasmus Handberg, Kuldeep Verma, Sarbani Basu, Luca Casagrande, Anders B. Justesen, Hans Kjeldsen, Jakob R. Mosumgaard
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29 pages, 27 Figures, 8 Tables, Accepted for publication in Apj
The advent of space-based missions like $Kepler$ has revolutionized the study of solar-type stars, particularly through the measurement and modeling of their resonant modes of oscillation. Here we analyze a sample of 66 $Kepler$ main-sequence stars showing solar-like oscillations as part of the $Kepler$ seismic LEGACY project. We use $Kepler$ short-cadence data, of which each star has at least 12 months, to create frequency power spectra optimized for asteroseismology. For each star we identify its modes of oscillation and extract parameters such as frequency, amplitude, and line width using a Bayesian Markov chain Monte Carlo `peak-bagging' approach. We report the extracted mode parameters for all 66 stars, as well as derived quantities such as frequency difference ratios, the large and small separations $Δν$ and $δν_{02}$; the behavior of line widths with frequency and line widths at $ν_{\rm max}$ with $T_{\rm eff}$, for which we derive parametrizations; and behavior of mode visibilities. These average properties can be applied in future peak-bagging exercises to better constrain the parameters of the stellar oscillation spectra. The frequencies and frequency ratios can tightly constrain the fundamental parameters of these solar-type stars, and mode line widths and amplitudes can test models of mode damping and excitation.
The Kepler Asteroseismic Legacy Project provided frequencies, separation ratios, error estimates, and covariance matrices for 66 Kepler main sequence targets. Most of the previous analysis of these data was focused on fitting standard stellar models. We present results of direct asteroseismic inversions using the method of optimally localized averages (OLA), which effectively eliminates the surface effects and attempts to resolve the stellar core structure. The inversions are presented for various structure properties, including the density stratification and sound speed. The results show that…
We use asteroseismic data from the Kepler satellite to determine fundamental stellar properties of the 66 main-sequence targets observed for at least one full year by the mission. We distributed tens of individual oscillation frequencies extracted from the time series of each star among seven modelling teams who applied different methods to determine radii, masses, and ages for all stars in the sample. Comparisons among the different results reveal a good level of agreement in all stellar properties, which is remarkable considering the variety of codes, input physics and analysis methods emplo…
I compare values of the frequencies, separation ratios, errors and covariance matrices from a new analysis of 9 solar-like stars with the Legacy project values reported by Lund et al and, for 16Cyg A&B and KIC8379927, with values derived by Davies et al. There is good agreement between my results (using Davies power spectra) and Davies's for these 3 stars, but no such agreement with the Legacy project results. My frequencies differ from the Legacy values, there are inconsistencies in the Legacy frequency covariance matrices which are not positive definite, and the Legacy errors on separation r…
In the past few years, the CoRoT and Kepler missions have carried out what is now called the space photometry revolution. This revolution is still ongoing thanks to K2 and will be continued by the Tess and Plato2.0 missions. However, the photometry revolution must also be followed by progress in stellar modelling, in order to lead to more precise and accurate determinations of fundamental stellar parameters such as masses, radii and ages. In this context, the long-lasting problems related to mixing processes in stellar interior is the main obstacle to further improvements of stellar modelling.…
We conduct a rigorous examination of the nearby red supergiant Betelgeuse by drawing on the synthesis of new observational data and three different modeling techniques. Our observational results include the release of new, processed photometric measurements collected with the space-based SMEI instrument prior to Betelgeuse's recent, unprecedented dimming event. We detect the first radial overtone in the photometric data and report a period of $185\pm13.5$ d. Our theoretical predictions include self-consistent results from multi-timescale evolutionary, oscillatory, and hydrodynamic simulations …
The TESS space mission provides us with high-precision photometric observations of bright stars over more than 70% of the entire sky, allowing us to revisit and characterise well-known stars. We aim to conduct an asteroseismic analysis of the gamma Doradus star HD112429 using both the available ground-based spectroscopy and TESS photometry, and assess the conditions required to measure the near-core rotation rate and buoyancy travel time. We collect and reduce the available five sectors of short-cadence TESS photometry of this star, as well as 672 legacy observations from six medium- to high-r…
Luminaries in the Sky: The TESS Legacy Sample of Bright Stars. I. Asteroseismic detections in naked-eye main-sequence and sub-giant solar-like oscillators
Asteroseismology is witnessing a revolution thanks to high-precise asteroseismic space data (MOST, CoRoT, Kepler, BRITE), and their large ground-based follow-up programs. Those instruments have provided an unprecedented large amount of information, which allows us to scrutinize its statistical properties in the quest for hidden relations among pulsational and/or physical observables. This approach might be particularly useful for stars whose pulsation content is difficult to interpret. This is the case of intermediate-mass classical pulsating stars (i.e. gamma Dor, delta Scuti, hybrids) for wh…
We performed a theoretical analysis on the relevance of the small frequency separation $δν$ in determining stellar ages, masses, and radii. We adopted the SCEPtER pipeline for low-mass stars, [0.7, 1.05] Msun. Synthetic stars were generated and reconstructed assuming different relative precision in $δν$ (5% and 2%). The quantification of the systematic errors arising from a mismatch between synthetic stars and the recovery grid was also performed. The biases were negligible. The statistical error in age estimates was strongly dependent on the stellar evolutionary phase. It is at its maximum at…
We use a high-precision radial velocity survey of FGKM stars to study the conditional occurrence of two classes of planets: close-in small planets (0.023--1 au, 2--30 Earth masses) and distant giant planets (0.23--10 au, 30--6000 Earth masses). We find that $41^{+15}_{-13}\%$ of systems with a close-in, small planet also host an outer giant, compared to $17.6^{+2.4}_{-1.9}\%$ for stars irrespective of small planet presence. This implies that small planet hosts may be enhanced in outer giant occurrence compared to all stars with $1.7σ$ significance. Conversely, we estimate that $42^{+17}_{-13}\…
Asteroseismic modelling of the internal structure of main-sequence stars born with a convective core has so far been based on homogeneous analyses of space photometric Kepler light curves of 4 years duration, to which most often incomplete inhomogeneously deduced spectroscopic information was added to break degeneracies. We composed a sample of 111 dwarf gravity-mode pulsators observed by the Kepler space telescope whose light curves allowed for determination of their near-core rotation rates. For this sample we assembled HERMES high-resolution optical spectroscopy at the 1.2-m Mercator telesc…
Asteroseismology is well-established in astronomy as the gold standard for determining precise and accurate fundamental stellar properties like masses, radii, and ages. Several tools have been developed for asteroseismic analyses but many of them are closed-source and therefore not accessible to the general astronomy community. Here we present $\texttt{pySYD}$, a Python package for detecting solar-like oscillations and measuring global asteroseismic parameters. $\texttt{pySYD}$ was adapted from the IDL-based $\texttt{SYD}$ pipeline, which was extensively used to measure asteroseismic parameter…
We present abundances of 21 elements in a sample of 13 bright FG dwarfs drawn from the Kepler LEGACY sample to examine the applicability of the abundance-age relations to stars with properties strongly departing from solar. These stars have precise asteroseismic ages that can be compared to the abundance-based estimates. We analyse the well-known binary 16 Cyg AB for validation purposes and confirm the existence of a slight metal enhancement (~0.02 dex) in the primary, which might arise from planetary formation/ingestion. We draw attention to systematic errors in some widely-used catalogues of…
Despite the fact that the initial helium abundance is an essential ingredient in modelling solar-type stars, its abundance in these stars remains a poorly constrained observational property. This is because the effective temperature in these stars is not high enough to allow helium ionization, not allowing any conclusions on its abundance when spectroscopic techniques are employed. To this end, stellar modellers resort to estimating the initial helium abundance via a semi-empirical helium-to-heavy element ratio, anchored to the the standard Big Bang nucleosynthesis value. Depending on the choi…
Detailed understanding of stellar physics is essential towards a robust determination of stellar properties (e.g. radius, mass, and age). Among the vital input physics used in the modelling of solar-type stars which remain poorly constrained, is the initial helium abundance. To this end, when constructing stellar model grids, the initial helium abundance is estimated either (i) by using the semi-empirical helium-to-heavy element enrichment ratio, (${ΔY}/{ΔZ}$), anchored to the standard Big Bang Nucleosynthesis value or (ii) by setting the initial helium abundance as a free variable. Adopting 3…
Asteroseismic modelling of main-sequence solar-like stars and Kepler exoplanet host stars with the FICO procedure I. Catalogue of fundamental stellar properties
Uppsala University（乌普萨拉大学）；Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CY Cergy Paris Université, CNRS（巴黎天文台，巴黎文理研究大学，索邦大学，巴黎西岱大学，CY塞吉-蓬图瓦兹大学，法国国家科学研究中心）；STAR Institute, Université de Liège（列日大学天体物理、恒星和系外行星研究所）；Istituto Nazionale di Astrofisica – Osservatorio Astronomico di Roma（意大利国家天体物理研究所罗马天文台）；Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP（波尔图大学空间科学与天体物理研究所）
Since the asteroseismic revolution, availability of efficient and reliable methods to extract stellar-oscillation mode parameters has been one of the keystone of modern stellar physics. In the helio- and asteroseismology fields, these methods are usually referred as peakbagging. We introduce in this paper the apollinaire module, a new Python 3 open-source Markov Chains Monte Carlo (MCMC) framework dedicated to peakbagging. The theoretical framework necessary to understand MCMC peakbagging methods for disk-integrated helio- and asteroseismic observations are extensively described. In particular…
We present the first data release of the Kepler Smear Campaign, using collateral 'smear' data obtained in the Kepler four-year mission to reconstruct light curves of 102 stars too bright to have been otherwise targeted. We describe the pipeline developed to extract and calibrate these light curves, and show that we attain photometric precision comparable to stars analyzed by the standard pipeline in the nominal Kepler mission. In this paper, aside from publishing the light curves of these stars, we focus on 66 red giants for which we detect solar-like oscillations, characterizing 33 of these i…
Luminaries in the Sky: The TESS LEGACY sample of bright stars. II. In-depth seismic characterisation of 32 naked-eye stars in the PLATO LOP fields
Université Paris Cité, Université Paris-Saclay, CEA, CNRS, AIM（巴黎西岱大学、巴黎萨克雷大学、法国原子能和替代能源委员会、法国国家科学研究中心）；School of Physics and Astronomy, University of Birmingham（伯明翰大学物理与天文学学院）；INAF – Osservatorio Astrofisico di Catania（意大利国家天体物理研究所卡塔尼亚天文台）；Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University（奥胡斯大学物理学与天文学系恒星天体物理学中心）；IMT Atlantique（大西洋高等理工学院）；Institut Villebon - Georges Charpak , Université Paris-Saclay（巴黎萨克雷大学维尔邦-乔治·夏帕克研究所）
The stellar activity-rotation-age relationship under the lens of asteroseismology
STAR Institute, Université de Liège（列日大学STAR研究所）；Department of Physics and Astronomy, Uppsala University（乌普萨拉大学物理与天文系）；Space Research Institute, Russian Academy of Sciences（俄罗斯科学院空间研究所）；Max Planck Institute for Astrophysics（马克斯·普朗克天体物理学研究所）；Kazan Federal University（喀山联邦大学）；Max-Planck-Institut für Sonnensystemforschung（马克斯·普朗克太阳系统研究所）；Astrophysics Research Center, Keele University（基尔大学天体物理研究中心）
The PLATO Science Calibration and Validation Plan: Targets for the First Long-pointing Field
Universität Innsbruck（因斯布鲁克大学）；KU Leuven（鲁汶大学）；Deutsches Zentrum für Luft- und Raumfahrt（德国航空航天中心）；Université Côte d’Azur（蔚蓝海岸大学）；Observatoire de la Côte d’Azur（蔚蓝海岸天文台）；CNRS（法国国家科学研究中心）；Laboratoire Lagrange（拉格朗日实验室）；Max Planck Institute for Solar System Research（马克斯·普朗克太阳系研究所）；Uppsala University（乌普萨拉大学）；INAF-Osservatorio Astrofisico di Catania（意大利国家天体物理研究所卡塔尼亚天文台）；Istituto Nazionale di Astrofisica (INAF)（意大利国家天体物理研究所）；Keele University（基尔大学）
