scholarly journals GG Carinae: orbital parameters and accretion indicators from phase-resolved spectroscopy and photometry

2020 ◽  
Author(s):  
Augustus Porter ◽  
David Grant ◽  
Katherine Blundell ◽  
Steven Lee
Keyword(s):  
Radial Velocity ◽  
Orbital Period ◽  
Initial Energy ◽  
Primary Component ◽  
Emission Lines ◽  
Circumstellar Envelopes ◽  
Orbital Parameters ◽  
History Of ◽  
Velocity Variations ◽  
Species Being

Abstract B[ e ] supergiants are a rare and unusual class of massive and luminous stars, characterised by opaque circumstellar envelopes. GG Carinae is a binary whose primary component is a B[ e ] supergiant and whose variability has remained unsatisfactorily explained. Using photometric data from ASAS, OMC, and ASAS-SN, and spectroscopic data from the Global Jet Watch and FEROS to study visible emission lines, we focus on the variability of the system at its ∼31-day orbital period and constrain the stellar parameters of the primary. There is one photometric minimum per orbital period and, in the emission line spectroscopy, we find a correlation between the amplitude of radial velocity variations and the initial energy of the line species. The spectral behaviour is consistent with the emission lines forming in the primary’s wind, with the variable amplitudes between line species being caused by the less energetic lines forming at larger radii on average. By modelling the atmosphere of the primary, we are able to model the radial velocity variations of the wind lines in order to constrain the orbit of the binary. We find that the binary is even more eccentric than previously believed (e = 0.5 ± 0.03). Using this orbital solution, the system is brightest at periastron and dimmest at apastron, and the shape of the photometric variations at the orbital period can be well described by the variable accretion by the secondary of the primary’s wind. We suggest that the evolutionary history of GG Carinae may need to be reevaluated in a binary context.

scholarly journals Fluorescence and Chromospheric Activity of V471 Tau

2002 ◽  
Vol 187 ◽  
pp. 167-172
Author(s):  
T.R. Vaccaro ◽  
R.E. Wilson
Keyword(s):  
Light Curve ◽  
Radial Velocity ◽  
Orbital Period ◽  
White Dwarf ◽  
Binary Star ◽  
Star Model ◽  
Orbital Inclination ◽  
Orbital Parameters ◽  
Maximum Emission ◽  
Chromospheric Activity

AbstractThe red dwarf + white dwarf eclipsing binary V471 Tau shows a variable Hα feature that varies from absorption during eclipse to maximum emission during white dwarf transit. In 1998 we obtained simultaneous BVRI photometry and Hα spectroscopy, with thorough phase coverage of the 12.5 hour orbital period. A binary star model was used with our light curve, radial velocity, and Hα data to refine stellar and orbital parameters. Combined absorption-emission profiles were generated by the model and fit to the observations, yielding a red star radius of 0.94R⊙. Orbital inclination 78° is required with this size and other known parameters. The model includes three spots 1,000 K cooler than the surrounding photosphere. The variable Hα profile was modeled as a chromospheric fluorescing region (essentially on the surface of the red star) centered at the substellar point. Additional emission seen outside our modeled profiles may be large co-rotating prominences that complicate the picture.

scholarly journals The multiple system Sk-67°18 in the LMC

1995 ◽  
Vol 163 ◽  
pp. 251-253 ◽  
Author(s):  
V. S. Niemela ◽  
W. Seggewiss ◽  
A. F. J. Moffat
Keyword(s):  
Binary System ◽  
Radial Velocity ◽  
Spectral Type ◽  
Orbital Period ◽  
Large Magellanic Cloud ◽  
Primary Component ◽  
Magellanic Cloud ◽  
Bright Star ◽  
High Mass ◽  
Eclipsing Binary

The bright star Sk—67°18 (Brey 5) in the Large Magellanic Cloud (LMC) contains an eclipsing binary system. Our radial velocity study reveals that the orbital period is almost exactly two days. The spectra also show that the star's primary component is not of spectral type WN, but that the star is rather an Of+O type binary where the primary is probably of type O3f*. Furthermore, Sk—67°18 appears to be a high-mass multiple system.

Dynamic versus Static Designation

2005 ◽  
Vol 13 ◽  
pp. 998-999
Author(s):  
Dimitri Pourbaix
Keyword(s):  
Data Structure ◽  
Radial Velocity ◽  
Orbital Period ◽  
Recent Progress ◽  
The Past ◽  
Lower Case ◽  
History Of ◽  
The Cross ◽  
Cross Reference

AbstractShould the designation of the components of a system reflect its known hierarchy or rather the history of their discovery? With the recent progress in, say, radial velocity techniques, the old famous order in which components were used to be discovered (inner to outer components for spectroscopic systems) is somehow altered. In the past, capital letters were used for visual companions and lower case letters for spectroscopic components and there was almost no overlap between the two groups. The situation has changed from both ends of the orbital period interval. In some rare cases, we think letters should be re-distributed and re-assigned in order to reflect the structure of the system. With an adequate choice of the data structure, such a change of the companion designation is rather straightforward to implement in modern databases (such as SB9). The only foreseen drawback is related to the cross-reference with some old papers: the letter B would not designate the same component in a 1970 paper and in a 2003 one. For instance, the former secondary of an SB2 system might now refer to the unseen companion and an astrometric triple.

scholarly journals Two new double-lined spectroscopic binary white dwarfs

2020 ◽  
Vol 493 (2) ◽  
pp. 2805-2816 ◽  
Author(s):  
Mukremin Kilic ◽  
A Bédard ◽  
P Bergeron ◽  
Alekzander Kosakowski
Keyword(s):  
Radial Velocity ◽  
White Dwarf ◽  
White Dwarfs ◽  
Binary Systems ◽  
Mass Ratio ◽  
Orbital Parameters ◽  
Long Period ◽  
Spectroscopic Binary ◽  
Velocity Variations ◽  
Period System

ABSTRACT We present radial velocity observations of four binary white dwarf candidates identified through their overluminosity. We identify two new double-lined spectroscopic binary systems, WD 0311–649 and WD 1606+422, and constrain their orbital parameters. WD 0311–649 is a 17.7 h period system with a mass ratio of 1.44 ± 0.06 and WD 1606+422 is a 20.1 h period system with a mass ratio of 1.33 ± 0.03. An additional object, WD 1447–190, is a 43 h period single-lined white dwarf binary, whereas WD 1418–088 does not show any significant velocity variations over time-scales ranging from minutes to decades. We present an overview of the 14 overluminous white dwarfs that were identified by Bédard et al., and find the fraction of double- and single-lined systems to be both 31 per cent. However, an additional 31 per cent of these overluminous white dwarfs do not show any significant radial velocity variations. We demonstrate that these must be in long-period binaries that may be resolved by Gaia astrometry. We also discuss the overabundance of single low-mass white dwarfs identified in the SPY survey, and suggest that some of those systems are also likely long-period binary systems of more massive white dwarfs.

scholarly journals Low–Mass He WDs and Millisecond Pulsars Age Determination

2000 ◽  
Vol 177 ◽  
pp. 631-632
Author(s):  
J. Antipova ◽  
Ene Ergma ◽  
M. J. Sarna
Keyword(s):  
Neutron Stars ◽  
Orbital Period ◽  
Time Scale ◽  
Age Determination ◽  
Close Binary ◽  
Orbital Parameters ◽  
History Of ◽  
Low Mass ◽  
Binary Evolution ◽  
Red Giant

It is accepted that the formation of a millisecond binary pulsar (MBP) with a low–mass companion may be explained as the end–point of close binary evolution in which an old pulsar is spun–up by accretion from the red giant (Bhattacharaya & van den Heuvel 1991). In this paper we shall discuss the cooling properties of the helium white dwarfs (WD) in short orbital period MBP systems PSR J0437–4715, PSR J0751+1807 and PSR J1012+5307, without referring to the rotational history of neutron stars (NS).Below we discuss observational data for several system for which the results of our calculations (Sarna, Antipova, & Muslimov 1998; Sarna, Ergma, & Antipova 1999) may be applied, by taking into account the orbital parameters of the system, the pulsar spin-down time, and the WD cooling time-scale.

scholarly journals Period dependent variations of the shell spectrum of V923 AQL

1994 ◽  
Vol 162 ◽  
pp. 374-375
Author(s):  
Lubomir Iliev
Keyword(s):  
Binary System ◽  
Radial Velocity ◽  
Orbital Period ◽  
Be Star ◽  
Low Mass ◽  
Velocity Variations

V923 Aql is a well known Be star with strong shell spectrum. It was included in the list of shell stars of Merrill and Burwell (1949). A detailed study of the radial velocity variations in the spectrum of the star based on wide collection of spectral observations was presented in the work of Koubsky et al. (1988). In this work an orbital period of 214.756 days was suggested for the binary system consisting of a B5–7 primary and low mass (0.5 Msol).

scholarly journals Activity in the circumstellar envelope of the Be/shell star ζ Tau

1994 ◽  
Vol 162 ◽  
pp. 372-373
Author(s):  
Yulian Guo ◽  
Lin Huang ◽  
Jinxin Hao
Keyword(s):  
Radial Velocity ◽  
Orbital Period ◽  
Absorption Lines ◽  
Circumstellar Envelope ◽  
Cyclic Variation ◽  
Spectroscopic Binary ◽  
Velocity Variations ◽  
Shell Star

ζ Tau is a well-known V/R-variable shell star. It is a single-lined spectroscopic binary with an orbital period of 133 days (Harmanec 1984, and Jarad 1987). Delplace (1970) found that the long-term radial velocity variations of the Balmer shell absorption lines are cyclic in 1960–67. Subsequently, similar behaviour has been observed and studied by several authors (Delplace and Chambon 1976, Hubert-Delplace et al 1983, Harmanec 1984, and Guo and Cao 1987). Mon et al (1992) showed that the cyclic variation had terminated and the star seems to have entered a new quiet phase around 1982.

scholarly journals Periodic Variations in the Spectrum of the Dwarf Nova WX Hyi in Outburst and Minimum

1987 ◽  
Vol 93 ◽  
pp. 143-143
Author(s):  
N. Vogt ◽  
M. Curé
Keyword(s):  
Radial Velocity ◽  
Equivalent Width ◽  
Center Of Mass ◽  
Emission Peak ◽  
Emission Lines ◽  
Absorption Lines ◽  
Quiescent State ◽  
Dwarf Nova ◽  
Thick Part ◽  
Velocity Variations

AbstractWe present the analysis of spectrograms obtained during quiescence and during an ordinary outburst of the SU UMa type dwarf nova WX Hyi (ESO 3.6m telescope, B&C spectrograph with Image Disector Scanner, 171 Åmm−1, range 4000–7000 Å, time resolution 6min.). The radial velocities of these spectra have been discussed by Schoembs and Vogt (1981) who also derived the orbital elements of WX Hyi. The phases φmax refer to these elements. All velocities discussed here are with respect to the white dwarf, not to the center of mass of the binary system.In quiescent state we did not find significant radial velocity variations. The equivalent widths Wλ of the He I emission lines revealed periodic variations with an amplitude of ≈30%, maximal values of Wλ were observed at φmax = 0.0... 0.2. In contrast, the equivalent widths of the Balmer lines were not variable.During outburst we found periodic radial velocity variations of the emission peak of Hα, Hβ and He I 5875 with an amplitude of ≈100 km s−l, φmax ≈ 0.5. Also the broad Balmer absorption lines revealed periodic radial velocity variations, with a similar amplitude (φmax = 0.3...0.5). The equivalent width of the Hα central emission peak varies with an amplitude of ≈30%, φmax ≈ 0.85. No variations of the equivalent width of the Balmer absorption lines were found.The outburst observations suggest that the preceeding part of the disc is brighter than the following one (in orbital motion). This is probably due to heating of the preceeding part by collisions with circumbinary matter, which seems to have an enhanced density in outburst as compared to the quiescent state. The emission lines are formed in outer layers or in a halo around the disc. The equivalent width variations can be interpreted in terms of interactions between this halo and the optically thick part of the disc.A more detailed discussion of the data is being published elsewhere.

scholarly journals The radial velocity variations of WR46 (WN3p)

1995 ◽  
Vol 163 ◽  
pp. 245-247
Author(s):  
V.S. Niemela ◽  
R.H. Barbá ◽  
M.M. Shara
Keyword(s):  
Binary System ◽  
Radial Velocity ◽  
Emission Lines ◽  
Strong Emission ◽  
X Ray ◽  
Emission Line Spectrum ◽  
Low Mass ◽  
Photometric Period ◽  
Velocity Variations ◽  
X Ray Binaries

Spectral observations of the WN3p star WR46 (HD 104994) obtained during June 1993 and January/February 1994 display large amplitude radial velocity variations of the strong emission lines Nv 4603-19Å and HeII 4686A, on a time scale of a fraction of a day. The most probable period found is 0.311 d, similar to the photometric period found by previous authors. The amplitude of the radial velocity variations of Nv emission is almost twice that of HeII. Noting the similarity of WR46 with low mass X-ray binaries, we suggest that the emission line spectrum corresponds to that of a luminous accretion disk in an evolved binary system.

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