scholarly journals Emission activity of the Be star 60 Cygni

2017 ◽  
pp. 51-57
Author(s):  
K. Sejnová ◽  
V. Votruba
Keyword(s):  
Time Evolution ◽  
Line Profile ◽  
Equivalent Width ◽  
Spectroscopic Analysis ◽  
Circumstellar Disk ◽  
Line Profiles ◽  
Emission Activity ◽  
Be Star

In this paper we present results of spectroscopic analysis of the H? line profile of the Be star 60 Cygni. We present time evolution of the equivalent width of the H? line profiles during years 1992 - 2016 and V=R variation during years 1995 - 2016. We analyzed data from Ond?ejov Observatory and from BeSS Database. The circumstellar disk of the star was present twice during years 1992 - 2016 and the second cycle shows stronger emission activity. We found out that the formation of the disk takes longer time than the disk extinction (the extinction is much steeper than the formation) and that there is no evident period of changes in the V=R variation.

scholarly journals A STUDY OF THE TIME VARIABILITY AND LINE PROFILE VARIATIONS OF κ DRA

2021 ◽  
Vol 57 (1) ◽  
pp. 91-105
Author(s):  
S. M. Saad ◽  
M. I. Nouh ◽  
A. Shokry ◽  
I. Zead
Keyword(s):  
Line Profile ◽  
Orbital Period ◽  
Circular Orbit ◽  
Spectroscopic Analysis ◽  
Emission Lines ◽  
Time Variability ◽  
Line Profiles ◽  
Orbital Elements ◽  
Balmer Lines ◽  
Be Star

We present a spectroscopic analysis of the bright Be star Κ Dra. Two independent sets of radial velocity (RV) measurements were obtained by direct measurement and using a line profile disentangling technique. By combining solutions from codes FOTEL and KOREL, we derived improved orbital elements. From the RVs of the Balmer lines and also from some strong metallic lines we found that all RV variations are phase-locked with the orbital period. V/R variations were obtained for Hα, Hβ, Hγ and some other photospheric lines. A moving absorption bump superposed over the emission line profiles was detected. The orbital solutions for Κ Dra were derived assuming a circular orbit with a period P = 61d.5549 and K = 6.81 km s−1. We failed to find absorption or emission lines for the unresolved secondary component.

scholarly journals Pulsations in 66 Oph: Multiperiodicity in He I 6678

2000 ◽  
Vol 175 ◽  
pp. 256-259 ◽  
Author(s):  
M. Floquet ◽  
C. Neiner ◽  
D. Briot ◽  
J. Chauville ◽  
A.M. Hubert ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Line Profile ◽  
Equivalent Width ◽  
Phase Distribution ◽  
Line Profiles ◽  
Short Term ◽  
Spectroscopic Observations

Abstract66 Oph has shown recurrent short-lived outbursts nicely detected from ground-based and space (Hipparcos) photometry.Spectroscopic observations of He I 6678 and Hα lines were performed in June 1997 and June 1998. Search for short-term periodicities was done in He I 6678 line profiles as in equivalent width EW, radial velocity of the line centroid, and V and R components. At least two frequencies were present: ν = 4.0 c/d and ν = 2.2 c/d. The phase distribution of these frequencies over the line profile corresponds in the nrp frame to g-modes with ℓ ~ 3 − 4 and ℓ = 2 respectively.

scholarly journals HR 4074: an Emission-Free NRP Twin of the Be Star 28 CMa

2002 ◽  
Vol 185 ◽  
pp. 248-249
Author(s):  
S. Štefl ◽  
Th. Rivinius ◽  
D. Baade
Keyword(s):  
Time Series ◽  
Line Profile ◽  
Rotational Velocity ◽  
Be Stars ◽  
Narrow Component ◽  
Rotational Modulation ◽  
Line Core ◽  
Emission Activity ◽  
History Of ◽  
Be Star

In spite of considerable progress in the investigation of rapid line-profile variations (lpv) of Be stars, at least two models still compete in the literature: the rotational modulation, assuming mostly corotating circumstellar structures (Balona, 2000), and nonradial pulsations (Maintz et al. and Rivinius et al., these proceedings). Attempts to explain the lpv of Be stars were often connected with the proto-typical star 28 (ω) CMa (HR 2749 = HD 56139, B2IV-Ve, v sin i = 80 km/s). Štefl et al. (1998) described variability in three line-profile components: in the narrow component of the line core, in the line core itself and in the wings. The Balmer emission of 28 CMa is variable and has always been observed to be at least moderate, mostly strong.HR 4074 (HD 89890, B3 III, v sin i = 70 km/s) has a different history of its emission activity. From a single spectrogram taken in 1893, Pickering (1898) reported an emission in Hβ. Subsequent observations never confirmed this. If it was not mis-identified by Pickering, HR 4074 would be in the probably longest B-star phase known of any Be star. HR 4074 is very probably not an SPB star - the spectral type is too early, the rotational velocity too high and light variations too low for this classification. Baade (1984) detected rapid lpv with a period P ≈ 2.25 d. Our time series analysis of radial velocity (RV) variations, measured as line modes, and that of full profiles give P = (2.3179 ± 0.0008) d.

scholarly journals Investigations of the MnI 539.47 nm and MnI 542.04 nm lines in solar plages

2005 ◽  
pp. 115-121 ◽  
Author(s):  
Istvan Vince ◽  
O. Gopasyuk ◽  
S. Gopasyuk ◽  
Oliver Vince
Keyword(s):  
Line Profile ◽  
Equivalent Width ◽  
Surface Coverage ◽  
Solar Surface ◽  
Activity Cycle ◽  
Full Width ◽  
Half Maximum ◽  
Line Profiles ◽  
Plage Region ◽  
Magnetic Filed

We observed the MnI 539.47 nm and 542.04nm line profiles in the quiet photosphere and plage regions in 1998 and 2001, and measured the full widths at half maximum, equivalent widths and depths of these profiles. The relative changes of the MnI 539.47 nm line parameters, normalized to the values obtained for quiet photosphere, as a function of magnetic field strength in plages is analyzed. We found, for plage region observed in 1998, that both the equivalent width and the depth of the line profile decrease with increasing strength of magnetic filed in plage at a rate of 9x10?4 /Gauss, but the full width at half maximum does not show any significant regular changes. Based on these results, the variations of the MnI 539.47 nm spectral line in solar flux with activity cycle could be explained by the variation of solar surface coverage with plages. For observations in 2001, the equivalent width and the depth of this line profile also decrease with increasing strength of magnetic filed in plage, but there are significant differences in the behavior of line parameters in comparison with the 1998 values. Comparison of changes of the MnI 539.47 nm line parameters with the parameters of the MnI 542.04 nm line in 1998 shows a clear discrepancy between them. On the contrary, in 2001 the full widths at half maximum and the equivalent widths of these two lines behaved in a similar fashion. .

scholarly journals Short-period Variations of 28 CMa during 1998/9

2000 ◽  
Vol 175 ◽  
pp. 236-239
Author(s):  
L.A. Balona ◽  
D. James
Keyword(s):  
Radial Velocity ◽  
Line Profile ◽  
Periodic Variation ◽  
Emission Lines ◽  
Circumstellar Disk ◽  
Be Stars ◽  
Short Period ◽  
Metal Absorption ◽  
Period Variations ◽  
Be Star

AbstractThe Be star 28 CMa was one of the first periodic Be stars to be discovered and shows very large line profile variations with a period of 1.37 d. Recently, it has been shown that the line profile and light variations can be modeled by a patch of gas suspended above the photosphere. We present echelle observations of the Hβ and Hϒ line and several helium and metal absorption lines. We show that the radial velocity variations of these lines are unchanged since they were first observed two decades ago. We also examined several emission lines of Fe II and show that they do not partake of the periodic variation. We attribute the periodic variations of the lines formed close to the photosphere to a co-rotating cloud, whereas the Fe II emission lines are formed in the circumstellar disk outside the co-rotating radius.

scholarly journals Activity of the Be star 28 Cygni: 1985–1991

1994 ◽  
Vol 162 ◽  
pp. 102-103
Author(s):  
Ž. Ružić ◽  
V. Vujnović ◽  
K. Pavlovski ◽  
H. Božić ◽  
J. R. Percy ◽  
...  
Keyword(s):  
Light Curve ◽  
Line Profile ◽  
Equivalent Width ◽  
Wind Profile ◽  
Spectroscopic Monitoring ◽  
Rapid Changes ◽  
Be Star ◽  
Ubv Photometry ◽  
The Mean

28 Cyg (V1624 Cyg, HD 191610, HR 7708; B2e, v sin i = 310 km s-1) has been the target of several observational projects, and in 1988 of a large international campaign. This attention was inspired by several photometric studies and especially by the 1985 nearly simultaneous optical and UV spectroscopic monitoring by Peters & Penrod (1988). They found that the line-profile variations were controlled by two frequencies, 1.45 c/d, and 7.43 c/d, which they identified with sectorial pulsations of modes l = 2, m = +2 and l = 10, m = +10. Rapid changes (0.5 to 1 hr) of the CIV wind profile were found; its equivalent width appeared to correlate with the phase of the l = 2 mode. Pavlovski & Ružić (1990) - who independently analysed Hvar 1985 UBV photometry of 28 Cyg - found periodic light variations with a double-wave light curve and a frequency of 1.54 c/d. However – because of the residual scatter around the mean light–curve – the authors tentatively suggested possible multiperiodicity (1.54, 1.33, and 0.95 c/d).

scholarly journals Global disk oscillations: theoretical line profiles

1994 ◽  
Vol 162 ◽  
pp. 382-383
Author(s):  
W. Hummel ◽  
R.W. Hanuschik
Keyword(s):  
Emission Line ◽  
Line Profile ◽  
Line Profiles ◽  
Circumstellar Envelopes ◽  
Be Star ◽  
Hα Emission ◽  
Line Transfer ◽  
Theoretical Line

Based on 3D radiative line transfer calculations we present Hα emission line profiles of Be star circumstellar envelopes undergoing one-armed global disk oscillations. The results are in agreement with the observed line profile variability.

The circumstellar disk of the Be star 28 (ω) CMa

2003 ◽  
Vol 6 ◽  
pp. 257-257
Author(s):  
S. Štefl ◽  
W. Nowotny-Schipper ◽  
J. Reunanen
Keyword(s):  
Circumstellar Disk ◽  
Be Star

scholarly journals The Kinematics of Quasar Broad Emission Line Regions Using a Disk-Wind Model

2017 ◽  
Vol 34 ◽  
Author(s):  
Suk Yee Yong ◽  
Rachel L. Webster ◽  
Anthea L. King ◽  
Nicholas F. Bate ◽  
Matthew J. O’Dowd ◽  
...  
Keyword(s):  
Emission Line ◽  
Line Profile ◽  
Inclination Angle ◽  
Opening Angle ◽  
Line Profiles ◽  
Wind Model ◽  
Disk Wind ◽  
Reverberation Mapping ◽  
Broad Emission ◽  
Line Region

AbstractThe structure and kinematics of the broad line region in quasars are still unknown. One popular model is the disk-wind model that offers a geometric unification of a quasar based on the viewing angle. We construct a simple kinematical disk-wind model with a narrow outflowing wind angle. The model is combined with radiative transfer in the Sobolev, or high velocity, limit. We examine how angle of viewing affects the observed characteristics of the emission line. The line profiles were found to exhibit distinct properties depending on the orientation, wind opening angle, and region of the wind where the emission arises.At low inclination angle (close to face-on), we find that the shape of the emission line is asymmetric, narrow, and significantly blueshifted. As the inclination angle increases (close to edge-on), the line profile becomes more symmetric, broader, and less blueshifted. Additionally, lines that arise close to the base of the disk wind, near the accretion disk, tend to be broad and symmetric. Single-peaked line profiles are recovered for the intermediate and equatorial wind. The model is also able to reproduce a faster response in either the red or blue sides of the line profile, consistent with reverberation mapping studies.

scholarly journals Apparent Variation of v sin i and Rotational Modulation in Be Stars

2004 ◽  
Vol 215 ◽  
pp. 93-94
Author(s):  
C. Neiner ◽  
S. Jankov ◽  
M. Floquet ◽  
A. M. Hubert
Keyword(s):  
Fourier Transform ◽  
Magnetic Dipole ◽  
Be Stars ◽  
Line Profiles ◽  
Transform Method ◽  
Rotational Modulation ◽  
Be Star ◽  
Apparent Variation ◽  
The Fourier Transform ◽  
First Time

v sin i was determined by applying the Fourier transform method to the line profiles of two classical Be Stars. A variation is observed in the apparent v sin i which corresponds to the main frequencies associated to nrp modes. Rotational modulation is observed in wind sensitive UV lines of the Be star ω Ori and is associated with an oblique magnetic dipole which is discovered for the first time in a classical Be star.

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