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Detecting binary stars in photometric time series is traditionally done by measuring eclipses. This requires the orbital plane to be aligned with the observer. A new method without that requirement uses stellar oscillations to measure…

太阳与恒星天体物理 · 物理学 2016-05-13 Douglas L. Compton , Timothy R. Bedding , Simon J. Murphy , Dennis Stello

Context: Stellar pulsations in main-sequence B-type stars are driven by the kappa-mechanism due to the Fe-group opacity bump. The current models do not predict the presence of instability strips in the B spectral domain at very low…

天体物理学 · 物理学 2009-11-13 P. D. Diago , J. Gutierrez-Soto , J. Fabregat , C. Martayan

We present an extensive survey for rapid pulsators among Extreme Horizontal Branch (EHB) stars in omega Cen. The observations performed consist of nearly 100 hours of time-series photometry, as well as low-resolution spectroscopy. We…

Hybrid $\delta$ Scuti-$\gamma$ Doradus pulsating stars show acoustic ($p$) oscillation modes typical of $\delta$ Scuti variable stars, and gravity ($g$) pulsation modes characteristic of $\gamma$ Doradus variable stars simultaneously…

太阳与恒星天体物理 · 物理学 2016-12-28 J. P. Sánchez Arias , A. H. Córsico , L. G. Althaus

We have explored the possibility of driving pulsation modes in models of sdO stars in which the effects of element diffusion, gravitational settling and radiative levitation have been neglected so that the distribution of iron-peak elements…

太阳与恒星天体物理 · 物理学 2015-05-14 C. Rodríguez-López , A. Moya , R. Garrido , J. MacDonald , R. Oreiro , A. Ulla

$\nu$ Eridani is a well known multiperiodic $\beta$ Cephei pulsator which exhibits also the SPB (Slowly Pulsating B-type stars) type modes. Recent frequency analysis of the BRITE photometry of $\alpha$ Lupi showed that the star is also a…

太阳与恒星天体物理 · 物理学 2017-01-06 Przemysław Walczak , Jadwiga Daszyńska-Daszkiewicz , Alexey Pamyatnykh , Gerald Handler , Andrzej Pigulski , BEST

Helium-star models were dynamically evolved into the region of the HR Diagram where R CrB variables are found. The MESA stellar evolution code was able to pick up pulsational instabilities with cycle lengths that are compatible with the…

太阳与恒星天体物理 · 物理学 2023-12-25 Alfred Gautschy

We examine the role of opacities in stellar pulsation with reference to Cepheids and RR Lyraes, and examine the effect of augmented opacities on the theoretical pulsation light curves in key temperature ranges. The temperature ranges are…

太阳与恒星天体物理 · 物理学 2018-06-11 S. M. Kanbur , M. Marconi , A. Bhardwaj , R. Kundu , H. P. Singh

Using linear non-adabatic pulsation analysis, we explore the radial-mode (p-mode) stability of stars across a wide range of mass (0.2 <= M <= 50 Msun), composition (0 <= X <= 0.7, Z=0.001, 0.02), effective temperature (3 000 <= T_eff <= 40…

太阳与恒星天体物理 · 物理学 2016-03-09 C. S. Jeffery , H. Saio

{\delta} Scuti variables are found at the intersection of the classical instability strip and the main sequence on the Hertzsprung-Russell diagram. With space-based photometry providing millions of light-curves of A-F type stars, we can now…

太阳与恒星天体物理 · 物理学 2024-05-31 Keyan Gootkin , Marc Hon , Daniel Huber , Daniel R. Hey , Timothy R. Bedding , Simon J. Murphy

There are different classes of pulsating stars in the H-R diagram. While many of those classes are undisputed, some remain a mystery such as the objects historically called "Maia variables". Whereas the presence of such a class was…

太阳与恒星天体物理 · 物理学 2024-09-13 F. Kahraman Aliçavuş , G. Handler , S. Chowdhury , E. Niemczura , R. Jayaraman , P. De Cat , D. Ozuyar , F. Aliçavuş

The analysis of the light curves of 48 B-type stars observed by Kepler is presented. Among these are 15 pulsating stars, all of which show low frequencies characteristic of SPB stars. Seven of these stars also show a few weak, isolated high…

The stable oscillations of pulsating stars can serve as accurate timepieces, which may be monitored for the influence of exoplanets. An external companion gravitationally tugs the host star, causing periodic changes in pulsation arrival…

太阳与恒星天体物理 · 物理学 2019-02-06 J. J. Hermes

The recent variability survey of the NGC 3766 cluster revealed a considerable number of periodic variable stars in a region of the H-R diagram where no pulsation is expected. This region lies between the instability strips of the delta…

太阳与恒星天体物理 · 物理学 2014-09-10 S. J. A. J. Salmon , J. Montalbàn , D. R. Reese , M. -A. Dupret , P. Eggenberger

Inspection of the periodograms of TESS delta Scuti stars indicates that there is little, if any, similarity between the frequencies of stars in the same region of the H-R diagram. This is difficult to understand because pulsation models…

太阳与恒星天体物理 · 物理学 2024-01-23 Luis A. Balona

We consider the excitation of radial and non-radial oscillations in low-mass B stars by the iron-bump opacity mechanism. The results are significant for the interpretation of pulsations in subdwarf B stars, helium-rich subdwarfs and extreme…

天体物理学 · 物理学 2009-11-11 C. S. Jeffery , H. Saio

Random changes in pulsation period occur in cool pulsating Mira variables, Type A, B, and C semiregular variables, RV Tauri variables, and in most classical Cepheids. The physical processes responsible for such fluctuations are uncertain,…

太阳与恒星天体物理 · 物理学 2011-02-23 David G. Turner , Leonid N. Berdnikov , J. R. Percy , Mohamed Abdel-Sabour Abdel-Latif

Massive B type pulsators such as beta Cep and slowly pulsating B (SPB) stars pulsate due to layers of increased opacity caused by partial ionization. The increased opacity blocks the energy flux to the surface of the stars which causes the…

天体物理学 · 物理学 2008-09-29 C. Karoff , T. Arentoft , L. Glowienka , C. Coutures , T. B. Nielsen , G. Dogan , F. Grundahl , H. Kjeldsen

Stellar pulsation is nowadays a widely understood subject. However, there has been no research about the effects of pulsations on the star's orbital dynamics throughout the galaxy. We investigate whether these oscillations can cause chaotic…

太阳与恒星天体物理 · 物理学 2022-09-20 Ronaldo S. S. Vieira , Ricardo A. Mosna

We have performed a linear pulsational stability survey of 6 series of long period variable models with M=1.0 Msun, L=3000 - 8000Lsun, and (X,Z)= (0.700,0.020),(0.735,0.005). The dynamic and thermodynamic couplings between convection and…

天体物理学 · 物理学 2009-10-30 D. R. Xiong , L. Deng , Q. L. Cheng