scholarly journals V772 Cas: an ellipsoidal HgMn star in an eclipsing binary

2020 ◽  
Vol 500 (2) ◽  
pp. 2577-2589
Author(s):  
O Kochukhov ◽  
C Johnston ◽  
J Labadie-Bartz ◽  
S Shetye ◽  
T A Ryabchikova ◽  
...  
Keyword(s):  
Brightness Variation ◽  
Primary Component ◽  
Eclipsing Binaries ◽  
High Resolution Spectroscopy ◽  
Eclipsing Binary ◽  
Fundamental Parameters ◽  
Chemically Peculiar ◽  
Photometric Observations ◽  
Peculiar Stars ◽  
Chemically Peculiar Stars

ABSTRACT The late B-type star V772 Cas (HD 10260) was previously suspected to be a rare example of a magnetic chemically peculiar star in an eclipsing binary system. Photometric observations of this star obtained by the TESS satellite show clear eclipses with a period of 5.0137 d accompanied by a significant out-of-eclipse variation with the same period. High-resolution spectroscopy reveals V772 Cas to be an SB1 system, with the primary component rotating about a factor two slower than the orbital period and showing chemical peculiarities typical of non-magnetic HgMn chemically peculiar stars. This is only the third eclipsing HgMn star known and, owing to its brightness, is one of the very few eclipsing binaries with chemically peculiar components accessible to detailed follow-up studies. Taking advantage of the photometric and spectroscopic observations available for V772 Cas, we performed modelling of this system with the phoebe code. This analysis provided fundamental parameters of the components and demonstrated that the out-of-eclipse brightness variation is explained by the ellipsoidal shape of the evolved, asynchronously rotating primary. This is the first HgMn star for which such variability has been definitively identified.

scholarly journals On-line database of photometric observations of magnetic chemically peculiar stars

2007 ◽  
Vol 328 (1) ◽  
pp. 10-15 ◽  
Author(s):  
Z. Mikulášek ◽  
J. Janík ◽  
J. Zverko ◽  
J. Žižňovský ◽  
M. Zejda ◽  
...  
Keyword(s):  
Chemically Peculiar ◽  
Photometric Observations ◽  
Peculiar Stars ◽  
On Line ◽  
Chemically Peculiar Stars

scholarly journals The nature of the photometric variability of HgMn stars: a test of simulated light curves of φ Phe against the TESS data

2019 ◽  
Vol 492 (2) ◽  
pp. 1834-1840 ◽  
Author(s):  
Milan Prvák ◽  
Jiří Krtička ◽  
Heidi Korhonen
Keyword(s):  
Light Curves ◽  
Heavy Elements ◽  
High Resolution Spectroscopy ◽  
Inhomogeneous Surface ◽  
Surface Distribution ◽  
Photometric Variability ◽  
Chemically Peculiar ◽  
Peculiar Stars ◽  
Chemically Peculiar Stars ◽  
Light Variability

ABSTRACT The inhomogeneous surface distribution of heavy elements is known to cause periodic light variability of magnetic chemically peculiar stars. It is unclear to what extent the same paradigm applies to mercury–manganese (HgMn) stars. We aim to model the photometric variability of the HgMn star φ Phe using abundance maps obtained from high-resolution spectroscopy and to study how this variability evolves with time. We compute a grid of atlas12 model atmospheres and the corresponding synspec synthetic spectra. Interpolating within this grid and integrating the specific intensity over the visible stellar surface at different rotational phases, we obtain theoretical light curves of the star. We predict the variability of φ Phe in the ultraviolet and in the visible spectral regions with amplitude of the order of millimagnitudes, mainly caused by absorption in lines of yttrium, chromium, and titanium. We also show how this variability is affected by changes of the distribution of the heavy elements over time. The main characteristics of the predicted light variability of φ Phe correspond roughly to the variability of the star observed with the Transiting Exoplanet Survey Satellite (TESS).

scholarly journals Fundamental parameters and evolutionary status of the magnetic chemically peculiar stars HD 188041 (V1291 Aquilae), HD 111133 (EP Virginis), and HD 204411: spectroscopy versus interferometry

2019 ◽  
Vol 488 (2) ◽  
pp. 2343-2356 ◽  
Author(s):  
A Romanovskaya ◽  
T Ryabchikova ◽  
D Shulyak ◽  
K Perraut ◽  
G Valyavin ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Measurement Errors ◽  
Chemical Elements ◽  
Model Fitting ◽  
Evolutionary Status ◽  
Fundamental Parameters ◽  
Chemically Peculiar ◽  
Peculiar Stars ◽  
Chemically Peculiar Stars ◽  
Ap Stars

ABSTRACT The determination of fundamental parameters of stars is one of the main tasks of astrophysics. For magnetic chemically peculiar stars, this problem is complicated by the anomalous chemical composition of their atmospheres, which requires special analysis methods. We present the results of the effective temperature, surface gravity, abundance, and radius determinations for three CP stars HD 188041, HD 111133, and HD 204411. Our analysis is based on a self-consistent model fitting of high-resolution spectra and spectrophotometric observations over a wide wavelength range, taking into account the anomalous chemical composition of atmospheres and the inhomogeneous vertical distribution for three chemical elements: Ca, Cr, and Fe. For two stars, HD 188041 and HD 204411, we also performed interferometric observations that provided us with the direct estimates of stellar radii. Comparison of the radii determined from the analysis of spectroscopic/spectrophotometric observations with direct measurements of the radii by interferometry methods for seven CP stars shows that the radii agree within the limits of measurement errors, which proves indirect spectroscopic analysis capable of proving reliable determinations of the fundamental parameters of fainter Ap stars that are not possible to study with modern interferometric facilities.

scholarly journals JD 16 – Spectroscopy With Large Telescopes of Chemically Peculiar Stars: Preface

1998 ◽  
Vol 11 (2) ◽  
pp. 645-645
Author(s):  
M. Takada-Hidai ◽  
J. Zverko
Keyword(s):  
High Resolution ◽  
Spectroscopic Studies ◽  
High Resolution Spectroscopy ◽  
Stellar Spectroscopy ◽  
Chemically Peculiar ◽  
Peculiar Stars ◽  
New Findings ◽  
Chemically Peculiar Stars ◽  
Large Telescopes ◽  
Near Future

The Keck 10-m telescope has begun to produce many new findings in a field of stellar spectroscopy with the help of the High Resolution Spectrograph (HIRES). The other large telescopes such as the Subaru, VLT, and Gemini are now being constructed and expected to perform high-resolution spectroscopy in a near future within several years or so. These highresolution spectroscopic studies will be carried out based on studies which have been made mainly with existing telescopes with aperture smaller than 4 m.

scholarly journals Time Resolved Photometric and Spectroscopic Analysis of Chemically Peculiar Stars

2014 ◽  
Vol 9 (S307) ◽  
pp. 218-219 ◽  
Author(s):  
Santosh Joshi ◽  
Gireesh C. Joshi ◽  
Y. C. Joshi ◽  
Rahul Aggrawal
Keyword(s):  
Time Series ◽  
Main Sequence ◽  
Spectroscopic Analysis ◽  
Time Resolved ◽  
Photometric Variability ◽  
Chemically Peculiar ◽  
Photometric Observations ◽  
Peculiar Stars ◽  
The Family ◽  
Chemically Peculiar Stars

AbstractHere we present the report on the “Nainital–Cape survey” research project aiming to search for and study the pulsational variability of main-sequence chemically peculiar (CP) stars. For this study, the time-series photometric observations of the sample stars were carried out at the 1.04 m ARIES telescope (India), while the high-resolution spectroscopic and spectro-polarimetric observations were carried out at the the 6.0 m Russian telescope. Under this project, we have recently found clear evidence of photometric variability in the Am star HD 73045, which is likely to be pulsating in nature with a period of about 36 min, hence adding a new member to the family of the δ Scuti pulsating variables that have peculiar abundances.

Extremely peculiar spectrum of the primary component of the eclipsing binary HD 66051

2019 ◽  
Vol 15 (S350) ◽  
pp. 412-414
Author(s):  
E. Niemczura ◽  
P. A. Kołaczek-Szymański ◽  
F. Castelli ◽  
S. Hubrig ◽  
S. P. Järvinen ◽  
...  
Keyword(s):  
Time Series ◽  
Time Series Data ◽  
Primary Component ◽  
Series Data ◽  
Physical Parameters ◽  
Orbital Parameters ◽  
Chemically Peculiar ◽  
Peculiar Stars ◽  
Chemically Peculiar Stars ◽  
Chemical Peculiarity

AbstractHD 66051 is an eclipsing and spectroscopic double-lined binary (SB2), hosting two chemically peculiar stars: a highly peculiar B star as primary and an Am star as secondary. The investigation of the new high-resolution UVES spectrum of HD 66051 allowed us to decide on the chemical peculiarity type of both components with more reliability. An analysis of TESS photometric time series data will further specify the physical parameters of the stars and the orbital parameters of the system.

scholarly journals Advanced test of the model stellar atmospheres: the nature of the light variability of magnetic chemically peculiar stars

2008 ◽  
Vol 4 (S252) ◽  
pp. 347-348
Author(s):  
J. Krtička ◽  
Z. Mikulášek ◽  
J. Zverko ◽  
J. Žižňovský ◽  
P. Zvěřina
Keyword(s):  
Chemical Elements ◽  
Horizontal Distribution ◽  
Stellar Atmospheres ◽  
Silicon Iron ◽  
Surface Distribution ◽  
Chemically Peculiar ◽  
Peculiar Stars ◽  
Distribution Of Elements ◽  
Chemically Peculiar Stars ◽  
Light Variability

AbstractThe magnetic chemically peculiar stars exhibit both inhomogeneous horizontal distribution of chemical elements on their surfaces and the light variability. We show that the observed light variability of these stars can be successfully simulated using models of their stellar atmospheres and adopting the observed surface distribution of elements. The most important elements that influence the light variability are silicon, iron, and helium.

scholarly journals 29. Stellar Spectra

1982 ◽  
Vol 18 (1) ◽  
pp. 343-360 ◽  
Author(s):  
W.K. Bonsack
Keyword(s):  
Stellar Evolution ◽  
Working Group ◽  
Main Sequence ◽  
Symbiotic Stars ◽  
Be Stars ◽  
Stellar Spectra ◽  
Chemically Peculiar ◽  
Peculiar Stars ◽  
Chemically Peculiar Stars ◽  
Ap Stars

During the interval covered by this report, Commission 29 has sponsored or cosponsored the following IAU meetings: Symposium 98 on “Be Stars,” Munich, FRG, April 1981; Colloquium 59, “Effects of Mass-Loss on Stellar Evolution,” Trieste, Italy, September 1980; and Colloquim 70, “The Nature of Symbiotic Stars,” Haute-Provence, France, August 1981. In addition, Commission 29, through its Working Group on Ap Stars, collaborated in the organization of the 23rd Liege International Astrophysical Symposium on Upper Main-Sequence Chemically Peculiar Stars. Several IAU symposia and colloquia proposed for 1982 and 1983 are also cosponsored by Commission 29.

scholarly journals K2 space photometry reveals rotational modulation and stellar pulsations in chemically peculiar A and B stars

2018 ◽  
Vol 616 ◽  
pp. A77 ◽  
Author(s):  
D. M. Bowman ◽  
B. Buysschaert ◽  
C. Neiner ◽  
P. I. Pápics ◽  
M. E. Oksala ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Intrinsic Variability ◽  
B Stars ◽  
Pulsating Stars ◽  
Chemically Peculiar ◽  
Large Scale Magnetic Field ◽  
Peculiar Stars ◽  
Show Evidence ◽  
Chemically Peculiar Stars

Context. The physics of magnetic hot stars and how a large-scale magnetic field affects their interior properties is largely unknown. Few studies have combined high-quality observations and modelling of magnetic pulsating stars, known as magneto-asteroseismology, primarily because of the dearth of detected pulsations in stars with a confirmed and well-characterised large-scale magnetic field. Aims. We aim to characterise observational signatures of rotation and pulsation in chemically peculiar candidate magnetic stars using photometry from the K2 space mission. Thus, we identify the best candidate targets for ground-based, optical spectropolarimetric follow-up observations to confirm the presence of a large-scale magnetic field. Methods. We employed customised reduction and detrending tools to process the K2 photometry into optimised light curves for a variability analysis. We searched for the periodic photometric signatures of rotational modulation caused by surface abundance inhomogeneities in 56 chemically peculiar A and B stars. Furthermore, we searched for intrinsic variability caused by pulsations (coherent or otherwise) in the amplitude spectra of these stars. Results. The rotation periods of 38 chemically peculiar stars are determined, 16 of which are the first determination of the rotation period in the literature. We confirm the discovery of high-overtone roAp pulsation modes in HD 177765 and find an additional 3 Ap and Bp stars that show evidence of high-overtone pressure modes found in roAp stars in the form of possible Nyquist alias frequencies in their amplitude spectra. Furthermore, we find 6 chemically peculiar stars that show evidence of intrinsic variability caused by gravity or pressure pulsation modes. Conclusions. The discovery of pulsations in a non-negligible fraction of chemically peculiar stars make these stars high-priority targets for spectropolarimetric campaigns to confirm the presence of their expected large-scale magnetic field. The ultimate goal is to perform magneto-asteroseismology and probe the interior physics of magnetic pulsating stars.

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