The Transiting Exoplanet Survey Satellite (TESS) is an all-sky survey mission aiming to search for exoplanets that transit bright stars. The high-quality photometric data of TESS are excellent for ...the asteroseismic study of solar-like stars. In this work, we present an asteroseismic analysis of the red-giant star HD 222076 hosting a long-period (2.4 yr) giant planet discovered through radial velocities. Solar-like oscillations of HD 222076 are detected around 203 Hz by TESS for the first time. Asteroseismic modeling, using global asteroseismic parameters as inputs, yields a determination of the stellar mass ( ), radius ( ), and age (7.4 2.7 Gyr), with precisions greatly improved from previous studies. The period spacing of the dipolar mixed modes extracted from the observed power spectrum reveals that the star is on the red-giant branch burning hydrogen in a shell surrounding the core. We find that the planet will not escape the tidal pull of the star and will be engulfed into it within about 800 Myr, before the tip of the red-giant branch is reached.
Abstract We report the discovery and characterization of TIC 350842552 (“Zvrk”), an apparently isolated, rapidly rotating ( P rot ∼ 99 days) red giant observed by TESS in its southern Continuous ...Viewing Zone. The star’s fast surface rotation is independently verified by the use of p -mode asteroseismology, strong periodicity in TESS and ASAS-SN photometry, and measurements of spectroscopic rotational broadening. A two-component fit to APOGEE spectra indicates a coverage fraction of its surface features consistent with the amplitude of the photometric rotational signal. Variations in the amplitude of its photometric modulations over time suggest the evolution of its surface morphology and therefore enhanced magnetic activity. We further develop and deploy new asteroseismic techniques to characterize radial differential rotation, but find at best only weak evidence for rotational shear within Zvrk’s convective envelope. This high surface rotation rate is incompatible with models of angular-momentum transport in single-star evolution. Spectroscopic abundance estimates also indicate a high lithium abundance, among other chemical anomalies. Taken together, all of these suggest a planet-ingestion scenario for the formation of this rotational configuration, various models for which we examine in detail.
Abstract
The Transiting Exoplanet Survey Satellite (TESS) mission searches for new exoplanets. The observing strategy of TESS results in high-precision photometry of millions of stars across the sky, ...allowing for detailed asteroseismic studies of individual systems. In this work, we present a detailed asteroseismic analysis of the giant star HD 76920 hosting a highly eccentric giant planet (
e
= 0.878) with an orbital period of 415 days, using five sectors of TESS light curve that cover around 140 days of data. Solar-like oscillations in HD 76920 are detected around 52
μ
Hz by TESS for the first time. By utilizing asteroseismic modeling that takes classical observational parameters and stellar oscillation frequencies as constraints, we determine improved measurements of the stellar mass (1.22 ± 0.11
M
⊙
), radius (8.68 ± 0.34
R
☉
), and age (5.2 ± 1.4 Gyr). With the updated parameters of the host star, we update the semimajor axis and mass of the planet as
a
= 1.165 ± 0.035 au and
M
p
sin
i
=
3.57
±
0.22
M
Jup
. With an orbital pericenter of 0.142 ± 0.005 au, we confirm that the planet is currently far away enough from the star to experience negligible tidal decay until being engulfed in the stellar envelope. We also confirm that this event will occur within about 100 Myr, depending on the stellar model used.
In this study, it was aimed to reveal the relationship between high school students’ music listening habits and their attitudes towards intangible cultural heritage elements. The research sample ...consists of 353 students studying at Isparta Süleyman Demirel Science High School. Research data were collected with a structured questionnaire. In the first part of the structured questionnaire consisting of three parts, there are questions to determine gender and grade, in the second part there are questions to determine the music listening habits of the students, and in the last part there is the Intangible Cultural Heritage Attitude Scale, the validity and reliability study of which was conducted by Gürel and Çetin (2019). The analyses within the scope of construct validity of the measurement tool were made and evaluated to be appropriate. In addition, as a result of the reliability analysis applied to the entire scale, Cronbach’s Alpha result was calculated as .871. Independent samples t-test and one-factor analysis of variance (ANOVA) were used to analyse the data obtained from the research. According to the results of the analyses, when the music listening habits of high school students and their attitudes towards intangible cultural heritage elements were examined, it was determined that there was no significant relationship according to gender, grade level, music listening tool, frequency of allocating special time for music listening and Turkish lyrics of music. In addition, it was determined that there was a significant difference between the type of music students listened to and their attitudes towards intangible cultural heritage elements.
Data from the space missions {\it Gaia}, {\it Kepler}, {\it CoRoT} and {\it TESS}, make it possible to compare parallax and asteroseismic distances. From the ratio of two densities \(\rho_{\rm ...sca}/\rho_{\pi}\), we obtain an empirical relation \(f_{\Delta \nu}\) between the asteroseismic large frequency separation and mean density, which is important for more accurate stellar mass and radius. This expression for main-sequence (MS) and subgiant stars with \(K\)-band magnitude is very close to the one obtained from interior MS models by Yıldız, Çelik \& Kayhan. We also discuss the effects of effective temperature and parallax offset as the source of the difference between asteroseismic and non-asteroseismic stellar parameters. We have obtained our best results for about 3500 red giants (RGs) by using 2MASS data and model values for \(f_{\Delta \nu}\) from Sharma et al. Another unknown scaling parameter \(f_{\nu_{\rm max}}\) comes from the relationship between the frequency of maximum amplitude and gravity. Using different combinations of \(f_{\nu_{\rm max}}\) and the parallax offset, we find that the parallax offset is generally a function of distance. The situation where this slope disappears is accepted as the most reasonable solution. By a very careful comparison of asteroseismic and non-asteroseismic parameters, we obtain very precise values for the parallax offset and \(f_{\nu_{\rm max}}\) for RGs of \(-0.0463\pm0.0007\) mas and \(1.003\pm0.001\), respectively. Our results for mass and radius are in perfect agreement with those of APOKASC-2: the mass and radius of \(\sim\)3500 RGs are in the range of about 0.8-1.8 M\(_{\odot}\) (96 per cent) and 3.8-38 R\(_{\odot}\), respectively.
The Transiting Exoplanet Survey Satellite (TESS) is performing a near all-sky survey for planets that transit bright stars. In addition, its excellent photometric precision enables asteroseismology ...of solar-type and red-giant stars, which exhibit convection-driven, solar-like oscillations. Simulations predict that TESS will detect solar-like oscillations in nearly 100 stars already known to host planets. In this paper, we present an asteroseismic analysis of the known red-giant host stars HD 212771 and HD 203949, both systems having a long-period planet detected through radial velocities. These are the first detections of oscillations in previously known exoplanet-host stars by TESS, further showcasing the mission's potential to conduct asteroseismology of red-giant stars. We estimate the fundamental properties of both stars through a grid-based modeling approach that uses global asteroseismic parameters as input. We discuss the evolutionary state of HD 203949 in depth and note the large discrepancy between its asteroseismic mass (M* = 1.23 0.15 M if on the red-giant branch or M* = 1.00 0.16 M if in the clump) and the mass quoted in the discovery paper (M* = 2.1 0.1 M ), implying a change >30% in the planet's mass. Assuming HD 203949 to be in the clump, we investigate the planet's past orbital evolution and discuss how it could have avoided engulfment at the tip of the red-giant branch. Finally, HD 212771 was observed by K2 during its Campaign 3, thus allowing for a preliminary comparison of the asteroseismic performances of TESS and K2. We estimate the ratio of the observed oscillation amplitudes for this star to be , consistent with the expected ratio of ∼0.85 due to the redder bandpass of TESS.
We report the discovery and characterisation of TIC 350842552 ("Zvrk"), an apparently isolated, rapidly-rotating (\(P_\text{rot} \sim 99\ \mathrm{d}\)) red giant observed by TESS in its Southern ...Continuous Viewing Zone. The star's fast surface rotation is independently verified by the use of p-mode asteroseismology, strong periodicity in TESS and ASAS-SN photometry, and measurements of spectroscopic rotational broadening. A two-component fit to APOGEE spectra indicates a coverage fraction of its surface features consistent with the amplitude of the photometric rotational signal. Variations in the amplitude of its photometric modulations over time suggest the evolution of its surface morphology, and therefore enhanced magnetic activity. We further develop and deploy new asteroseismic techniques to characterise radial differential rotation, and find weak evidence for rotational shear within Zvrk's convective envelope. This feature, in combination with such a high surface rotation rate, is incompatible with models of angular-momentum transport in single-star evolution. Spectroscopic abundance estimates also indicate a high lithium abundance, among other chemical anomalies. Taken together, all of these suggest a planet-ingestion scenario for the formation of this rotational configuration, various models for which we examine in detail.
ABSTRACT
The Transiting Exoplanet Survey Satellite (TESS) is recording short-cadence, high duty-cycle timeseries across most of the sky, which presents the opportunity to detect and study ...oscillations in interesting stars, in particular planet hosts. We have detected and analysed solar-like oscillations in the bright G4 subgiant HD 38529, which hosts an inner, roughly Jupiter-mass planet on a $14.3\, \mathrm{d}$ orbit and an outer, low-mass brown dwarf on a $2136\, \mathrm{d}$ orbit. We combine results from multiple stellar modelling teams to produce robust asteroseismic estimates of the star’s properties, including its mass $M=1.48\pm 0.04\, \mathrm{M}_\odot {}$, radius $R=2.68\pm 0.03\, \mathrm{R}_\odot {}$, and age $t=3.07\pm 0.39\, \mathrm{Gyr}{}$. Our results confirm that HD 38529 has a mass near the higher end of the range that can be found in the literature and also demonstrate that precise stellar properties can be measured given shorter timeseries than produced by CoRoT, Kepler, or K2.
Tez çalışmamızda Bulgar edebiyatının Türkiye'de yer alma süreci tarihsel çerçevede neden ve sonuçlarıyla incelenmiştir. Geçmişten günümüze çevrilen kitapların sayısının Türkiye ve Bulgaristan'daki ...toplumsal ve kültürel tablolardan etkilendiği görülmüştür. Bu sebeple, çeviri süreci, bahsi geçen olayların yarattığı etkiye göre on ya da yirmi yılı kapsayan dönemler halinde ele alınmıştır. Çalışmanın birinci bölümünde Türkiye'deki çeviri faaliyetlerinin seyrine göz atılmış, çevirinin Türkiye'deki etkisi tartışılmıştır. İkinci bölümde Bulgar edebiyatının Türkiye'de ilgi uyandıran özellikleri belirtilerek, ülkemizde yer alma süreci ve ilk çevirilere değinilmiştir. Üçüncü bölümden itibaren çalışmanın ana konusunu oluşturan her iki ülkedeki tarihsel seyrin çeviriye etkisi, karşılaştırmalı olarak her bölümde ele alınmış, çeviri kitap verileri analiz edilmiş ve ulaşılan bulgunun neden ve sonuçları üzerinde durulmuştur. Bölüm başlıkları kronolojik bir çerçevede sunulmuştur. Elde edilen veriler, yıl, tür, yazar ya da çevirmen tercihi açısından bulunduğu dönemin etkisi dikkate alınarak sınıflandırılmış ve değerlendirilmiştir. Ayrıca, yapılan çevirilerin Türk okuyucusunda nasıl bir etki yarattığı tartışılmıştır. Çalışmanın sonuç kısmında, ulaşılan bulgular değerlendirilmiş ve Bulgarcadan çeviri faaliyetlerinin seyri konusunda önerilerde bulunulmuştur.
When main-sequence stars expand into red giants, they are expected to engulf close-in planets. Until now, the absence of planets with short orbital periods around post-expansion, core-helium-burning ...red giants has been interpreted as evidence that short-period planets around Sun-like stars do not survive the giant expansion phase of their host stars. Here we present the discovery that the giant planet 8 Ursae Minoris b orbits a core-helium-burning red giant. At a distance of only 0.5 au from its host star, the planet would have been engulfed by its host star, which is predicted by standard single-star evolution to have previously expanded to a radius of 0.7 au. Given the brief lifetime of helium-burning giants, the nearly circular orbit of the planet is challenging to reconcile with scenarios in which the planet survives by having a distant orbit initially. Instead, the planet may have avoided engulfment through a stellar merger that either altered the evolution of the host star or produced 8 Ursae Minoris b as a second-generation planet. This system shows that core-helium-burning red giants can harbour close planets and provides evidence for the role of non-canonical stellar evolution in the extended survival of late-stage exoplanetary systems.
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