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In the first spectroscopic campaign for a PG 1716 variable (or long-period pulsating subdwarf B star), we succeeded in detecting velocity variations due to g-mode pulsations at a level of 1.0-1.5 km/s.The observations were obtained during…

We present interpretation of the oscillation spectrum of the early B-type star $\gamma$ Pegasi, in which both low order p/g and high-order g-modes are observed. Using amplitudes and phases of the photometric and radial velocity variations,…

Solar and Stellar Astrophysics · Physics 2015-06-15 Przemysław Walczak , Jadwiga Daszyńska-Daszkiewicz , Alexey A. Pamyatnykh , Tomasz Zdravkov

M-type stars exhibit strong magnetic fields towards decreasing effective temperatures. The measurement of these fields is complicated due to missing indicators. Molecular FeH lines provide an excellent means to determine magnetic field…

Solar and Stellar Astrophysics · Physics 2010-11-30 Sebastian Wende , Ansgar Reiners , Andreas Seifahrt , Denis Shulyak , Oleg Kochukhov

The goal of this work is to study magnetic fields of the cool, eclipsing binary star UV Piscium (UV Psc). This system contains two active late-type stars, UV Psc A (G5V) and B (K3V). To obtain a complete picture, the properties of both…

Solar and Stellar Astrophysics · Physics 2021-06-30 A. Hahlin , O. Kochukhov , E. Alecian , J. Morin , the BinaMIcS collaboration

$\xi^1$ CMa is a monoperiodically pulsating, magnetic $\beta$ Cep star with magnetospheric X-ray emission which, uniquely amongst magnetic stars, is clearly modulated with the star's pulsation period. The rotational period $P_{\rm rot}$ has…

Solar and Stellar Astrophysics · Physics 2017-06-28 M. Shultz , G. A. Wade , Th. Rivinius , C. Neiner , H. Henrichs , W. Marcolino , the MiMeS Collaboration

High-resolution circular spectropolarimetric observations, obtained with ESPaDOnS in the context of the BinaMIcS Large Program, have revealed a magnetic field in the B3V secondary component of the SB2 binary system $\epsilon$ Lupi (B2/B3).…

Solar and Stellar Astrophysics · Physics 2015-09-30 M. Shultz , G. A. Wade , E. Alecian , the BinaMIcS Collaboration

Magnetic fields connect an array of planetary processes, from atmospheric escape to interior convection. Despite their importance, exoplanet magnetic fields are largely unconstrained by both theory and observation. In this Letter, we…

Earth and Planetary Astrophysics · Physics 2024-06-25 Arjun B. Savel , Hayley Beltz , Thaddeus D. Komacek , Shang-Min Tsai , Eliza M. -R. Kempton

In order to understand the periodic and semi-periodic variations of luminous O- B- A-type stars, linear nonadiabatic stability analyses for radial and nonradial oscillations have been performed for massive evolutionary models ($8M_\odot -…

Solar and Stellar Astrophysics · Physics 2015-05-20 Hideyuki Saio

The origin of magnetic fields in intermediate-mass and high-mass stars is fundamentally a mystery. Clues toward solving this basic astrophysical problem can likely be found at the pre-main sequence (PMS) evolutionary stage. With this work,…

Astrophysics · Physics 2008-11-26 G. A. Wade , S. Bagnulo , D. Drouin , J. D. Landstreet , D. Monin

Today, one of the greatest challenges concerning the Ap/Bp stars is to understand the origin of their slow rotation and their magnetic fields. The favoured hypothesis for the latter is the fossil field, which implies that the magnetic…

We report the systematic detection of magnetic fields in massive (M > 5 M$_\odot$) late-type supergiants, using spectropolarimetric observations obtained with ESPaDOnS at the Canada-France-Hawaii Telescope. Our observations reveal…

Solar and Stellar Astrophysics · Physics 2015-05-19 Jason H. Grunhut , Gregg A. Wade , David A. Hanes , Evelyne Alecian

We have studied a sample of 28 periodically variable B-type supergiants selected from the HIPPARCOS mission and 12 comparison stars covering the whole B-type spectral range. Our goal is to test if their variability is compatible with…

Astrophysics · Physics 2009-10-15 K. Lefever , J. Puls , C. Aerts

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…

Astrophysics · Physics 2009-11-13 P. D. Diago , J. Gutierrez-Soto , J. Fabregat , C. Martayan

Context: About 10% of white dwarfs have magnetic fields with strength in the range between about 10^5 and 3x10^8 G. It is not known whether the remaining white dwarfs are not magnetic, or if they have a magnetic field too weak to be…

Solar and Stellar Astrophysics · Physics 2015-06-11 J. D. Landstreet , S. Bagnulo , G. G. Valyavin , L. Fossati , S. Jordan , D. Monin , G. Wade

The frequent presence of weak magnetic fields on the surface of spotted late-B stars with HgMn peculiarity in binary systems has been controversial during the two last decades. We re-analyse available spectropolarimetric material by…

Solar and Stellar Astrophysics · Physics 2015-06-11 S. Hubrig , J. F. Gonzalez , I. Ilyin , H. Korhonen , M. Schoeller , I. Savanov , R. Arlt , F. Castelli , G. Lo Curto , M. Briquet , T. H. Dall

Soft gamma repeaters and anomalous x-ray pulsars form a rapidly increasing group of x-ray sources exhibiting sporadic emission of short bursts. They are believed to be magnetars, i.e. neutron stars powered by extreme magnetic fields,…

High Energy Astrophysical Phenomena · Physics 2015-05-20 N. Rea , P. Esposito , R. Turolla , G. L. Israel , S. Zane , L. Stella , S. Mereghetti , A. Tiengo , D. Gotz , E. Gogus , C. Kouveliotou

Beta Cephei-type variables are early B-type stars that are characterized by oscillations observable in their optical light curves. At least one Beta Cep-variable also shows periodic variability in X-rays. Here we study the X-ray light…

Solar and Stellar Astrophysics · Physics 2015-04-29 L. M. Oskinova , H. Todt , D. P. Huenemoerder , S. Hubrig , R. Ignace , W. -R. Hamann , L. Balona

Substantial progress has been achieved over the last decade in studies of stellar magnetism due to the improvement of magnetic field measurement methods. We review recent results on the magnetic field characteristics of early B- and O-type…

Solar and Stellar Astrophysics · Physics 2016-03-01 S. Hubrig , M. Schoeller , A. F. Kholtygin , L. M. Oskinova , I. Ilyin

The radio pulsar GLEAM-X J162759.5-523504.3 has an extremely long spin period ($P = 1091.17\, \mbox{s}$), and yet seemingly continues to spin down rapidly ($\dot{P} < 1.2 \times 10^{-9}\, \mbox{ss}^{-1}$). The magnetic field strength that…

High Energy Astrophysical Phenomena · Physics 2023-01-27 Arthur G. Suvorov , Andrew Melatos

Context: [abbreviated] Aims: Kepler data of three known Be stars are re-visited to establish their pulsational nature and assess the properties of additional, non-pulsational variations. The three program stars turned out to be one inactive…

Solar and Stellar Astrophysics · Physics 2016-10-05 Thomas Rivinius , Dietrich Baade , Alex Carciofi