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A majority part of magnetic chemically peculiar (mCP) stars of the upper main sequence exhibits strictly periodic light, magnetic, radio, and spectral variations that can be fully explained by the model of a rigidly rotating main-sequence…

Solar and Stellar Astrophysics · Physics 2017-02-27 Zdeněk Mikulášek

Stars are not perfectly spherically symmetric. They are deformed by rotation and magnetic fields. Until now, the study of stellar shapes has only been possible with optical interferometry for a few of the fastest-rotating nearby stars. We…

Transit timing variations of Kepler-410Ab were already reported in a few papers. Their semi-amplitude is about 14.5 minutes. In our previous paper, we found that the transit timing variations could be caused by the presence of a stellar…

We measure the mean Galactocentric radial component of the velocity of stars ($v_R$) in the disk at 8 kpc$<R<28$ kpc in the direction of the anticenter. For this, we use the Apache Point Galactic Evolution Experiment (APOGEE). Furthermore,…

Astrophysics of Galaxies · Physics 2019-02-26 M. Lopez-Corredoira , F. Sylos Labini , P. M. W. Kalberla , C. Allende Prieto

The observed velocities of radio pulsars, which range in the hundreds kilometers per second, and many of which exceed 1000 km/s, are not explained by the standard physics of the supernova explosion. However, if a sterile neutrino with mass…

Astrophysics · Physics 2009-11-10 Alexander Kusenko

GAIA spectroscopic and radial velocity performancies are reviewed on the base of ground-based test observations and simulations. The prospects for accurate analysis of stellar atmospheres (temperature, gravity, chemical abundances,…

Astrophysics · Physics 2015-06-24 Ulisse Munari

We have used many decades of visual observations from the AAVSO International Database, and the AAVSO time-series analysis package VSTAR, to study the long-term changes in period, amplitude, and mean magnitude in about 30 normal pulsating…

Solar and Stellar Astrophysics · Physics 2018-05-29 John R. Percy , Arthur Lei Qiu

The nearby brown dwarf LP 944-20 has been monitored for radial velocity variability at optical and near-infrared wavelengths using the VLT/UVES and the Keck/NIRSPEC spectrographs, respectively. The UVES radial velocity data obtained over 14…

Astrophysics · Physics 2009-11-11 E. L. Martin , E. Guenther , M. R. Zapatero Osorio , H. Bouy , R. Wainscoat

Instability of population I (X=0.7, Y=0.02) massive stars against radial oscillations during the post-main sequence gravitational contraction of the helium core is investigated. Initial stellar masses are in the range from 65M_\odot to…

Solar and Stellar Astrophysics · Physics 2015-05-27 Yuri A. Fadeyev

The `radio sky' is relatively unexplored for transient signals, although the potential of radio-transient searches is high, as demonstrated recently by the discovery of a previously unknown type of source which varies on timescales of…

We present the peculiar in-plane velocities derived from the LAMOST red clump stars. From the variations of the in-plane velocity with the Galactocentric radius for the young and old red clump stars, we are able to identify two types of…

Astrophysics of Galaxies · Physics 2017-12-20 Hai-Jun Tian , Chao Liu , Jun-Chen Wan , Li-Cai Deng , Zi-Huang Cao , Yong-Hui Hou , Yong Zhang , Yue-Fei Wang , Yue Wu , Yong-Heng Zhao

In this paper we search for distant massive companions to known transiting gas giant planets that may have influenced the dynamical evolution of these systems. We present new radial velocity observations for a sample of 51 planets obtained…

We present the results of a study aimed at assessing whether low and high mass stars form similarly. Our approach is (1) to examine the observed projected rotational velocities among a large sample of newly-formed stars spanning a range in…

Astrophysics · Physics 2008-11-26 S. C. Wolff , S. E. Strom , D. Dror , L. Lanz , K. Venn

New high-cadence observations with BRITE covering many months confirm that coupled pairs of nonradial pulsation modes are widespread among early-type Be stars. With the difference frequency between the parental variations they may form a…

We measured the radial-velocity curve of HD77581, the B-supergiant companion of the X-ray pulsar Vela X-1, using 183 high-resolution optical spectra obtained in a nine-month campaign. We derive radial-velocity amplitudes for different lines…

Astrophysics · Physics 2009-11-07 O. Barziv , L. Kaper , M. H. van Kerkwijk , J. H. Telting , J. van Paradijs

The giant planet occurrence rate rises with orbital period out to at least $\sim$300 days. Large-scale planetary migration through the disk has long been suspected to be the physical origin of this feature, as the timescale of standard Type…

Earth and Planetary Astrophysics · Physics 2020-12-09 Tim Hallatt , Eve J Lee

The majority of magnetic chemically peculiar (mCP) stars exhibit periodic light, magnetic, radio, and spectroscopic variations that can be adequately modelled as a rigidly-rotating main-sequence star with persistent surface structures.…

We report that the spectroscopic binary ? Ursae Majoris (?mu UMa) has secondary RV variations of 471.2 days in addition to those of 230.0 days already known. Keplerian orbit analysis yields stellar mass companions of 1.6 M_Sun for the 230-d…

Solar and Stellar Astrophysics · Physics 2016-04-20 Byeong-Cheol Lee , Inwoo Han , Myeong-Gu Park , David E. Mkrtichian , Artie P. Hatzes , Gwanghui Jeong , Kang-Min Kim

As part of a radial velocity survey of low Galactic latitude structures that we undertook with the 2dF spectrograph on the AAT, we present the radial velocities of more than 1500 Red Giant Branch and Red Clump stars towards the centre of…

Astrophysics · Physics 2009-11-10 N. F. Martin , R. A. Ibata , B. C. Conn , G. F. Lewis , M. Bellazzini , M. J. Irwin

This study presents the rotational distribution of red giant stars (RGs) in eleven old to intermediate age open clusters. The masses of these stars are all above the Kraft break, so that they lose negligible amounts of their birth angular…

Solar and Stellar Astrophysics · Physics 2015-06-19 Joleen K. Carlberg
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