scholarly journals GG Carinae: discovery of orbital-phase-dependent 1.583-day periodicities in the B[e] supergiant binary

2021 ◽  
Vol 503 (4) ◽  
pp. 4802-4814
Author(s):  
Augustus Porter ◽  
Katherine Blundell ◽  
Philipp Podsiadlowski ◽  
Steven Lee
Keyword(s):  
Orbital Period ◽  
Primary Component ◽  
Emission Lines ◽  
Optical Monitoring ◽  
Eccentric Orbit ◽  
Tidal Forces ◽  
Short Period ◽  
Period Variations ◽  
Orbital Phase ◽  
Monitoring Camera

ABSTRACT GG Carinae (GG Car) is a binary whose primary component is a B[e] supergiant. Using photometric data from the Transiting Exoplanet Survey Satellite (TESS), All Sky Automated Survey (ASAS), Optical Monitoring Camera (OMC), and All Sky Automated Survey for Supernovae (ASAS-SN), and spectroscopic data from the Global Jet Watch to study visible He i, Fe ii, and Si ii emission lines, we investigate the short-period variations that are exhibited in GG Car. We find a hitherto neglected periodicity of 1.583156 ± 0.0002 d that is present in both its photometry and the radial velocities of its emission lines, alongside variability at the well-established ∼31-d orbital period. We find that the amplitudes of the shorter period variations in both photometry and some of the emission lines are modulated by the orbital phase of the binary, such that the short-period variations have largest amplitudes when the binary is at periastron. There are no significant changes in the phases of the short-period variations over the orbital period. We investigate potential causes of the 1.583-d variability, and find that the observed period agrees well with the expected period of the l = 2 f-mode of the primary given its mass and radius. We propose that the primary is periodically pulled out of hydrostatic equilibrium by the quadrupolar tidal forces when the components are near periastron in the binary’s eccentric orbit (e = 0.5) and the primary almost fills its Roche lobe. This causes an oscillation at the l = 2 f-mode frequency that is damped as the distance between the components increases.

scholarly journals Observations of Southern Dwarf Novae

1979 ◽  
Vol 53 ◽  
pp. 497-497
Author(s):  
N. Vogt
Keyword(s):  
Orbital Period ◽  
White Dwarf ◽  
Photometric Data ◽  
Emission Lines ◽  
List Type ◽  
Type Number ◽  
Dwarf Novae ◽  
Broad Emission ◽  
Cataclysmic Binaries ◽  
Short Period

Preliminary results of spectroscopic and photometric data for five dwarf novae are presented : 1) V 436 Cen. The orbital period of 0.0669 days was determined from radial velocity variations. The RV half amplitude of the primary, K1. = 159 km/s, implies very small masses of M1 ≲ 0.20 M⊙ and M2 = 0.18 M⊙ for the binary components.2) Z Cha. Broad emission (Hβ, Hγ, Hδ) and superimposed narrow absorption lines of Hβ-HII, HeI 4471, Cal 4427 and Call K characterize the spectrum during quiescence. Apparently, the cool, optically thin outer disc is seen on the background of a hot continuum, originating from the white dwarf or the inner disc. The RV half amplitude K1 = 87 km/s results in masses of M1 = 1.10 M⊙ and M⊙ = 0.21 M⊙.3) EX Hya. The RV half amplitude K1 = 68 km/s reveals masses of M1 = 1.4 M⊙ and M2 = 0.19 M⊙ The equivalent widths of the emission lines of H, HeI 4471 and HeII 4686 vary with the phase of the recently detected 67 minute cycle (maximal EW coincides nearly with maximal continuum intensity).4) 0Y Car is an eclipsing binary with an orbital period of 0.0631 days. The eclipses show strong variations in shape and amplitude in the course of an outburst, similar as those of Z Cha. The observations seem to confirm that the location of the eruption is the central part of the disc which increases in size and luminosity.5) EK TrA shows periodic superhumps (P = 0.0645 days) during supermaximum, and therefore belongs to the SU UMa sub-group of dwarf novae which are also characterized by a quasi-periodic occurence of super-maxima. The SU UMa sub-group comprises 70% of the ultra-short period cataclysmic binaries, and at least 18% of all dwarf novae.

scholarly journals Wind-wind collision effects in close massive WR+O binaries

1995 ◽  
Vol 163 ◽  
pp. 397-405
Author(s):  
S.V. Marchenko
Keyword(s):  
Ionization Potential ◽  
Orbital Period ◽  
Bow Shock ◽  
Emission Lines ◽  
Line Profiles ◽  
Emission Component ◽  
Shock Region ◽  
Orbital Phase

A detailed description of the wind-wind collision (WWC) zones in the Wolf-Rayet binaries V444 Cyg (WN5+O6III-V, P = 4.21 d) and CX Cep (WN5+O5V, P = 2.13 d) is presented. In V444 Cyg, parameters of the WWC zone can be derived from variations of HeI line profiles. There is some evidence for a highly unstable character of the WWC zone. In CX Cep, the complicated dependence of equivalent widths for emission lines of different ionization potential on orbital phase can be explained by a combination of several factors, e.g., (a) additional ionization from the bow shock region; (b) reheating of the WR wind by the O-star companion; and (c) an emission component arising in the WWC region. Some preliminary indications of WWC are revealed in the WR+OB system CQ Cep (WN7+O9I-II?) with the shortest known orbital period: P = 1.64 d.

scholarly journals Accretion and pulsation of IU Per based on INTEGRAL and ground base photometry

2012 ◽  
Vol 8 (S290) ◽  
pp. 377-378
Author(s):  
Emil Kundra ◽  
Ladislav Hric ◽  
Rudolf Gális
Keyword(s):  
Primary Component ◽  
Light Curves ◽  
Optical Monitoring ◽  
Short Term ◽  
Period Analysis ◽  
Massive Component ◽  
Monitoring Camera ◽  
Pulsation Activity ◽  
Scuti Stars ◽  
Δ Scuti Stars

AbstractIU Persei (IU Per) is an eclipsing semi detached (SD) binary with pulsating component (oscillating eclipsing Algol - oEA). Using our ground base photometry in Johnson's B and V filters and INTEGRAL/OMC (Optical Monitoring Camera) data in V filter we introduce the model of this system. We determined the (O - C) diagram behavior. Moreover, the short term variations of the light curve were detected. Whats more, we obtained residua, by comparison of observational and synthetic light curves (LC), of which the detailed period analysis enabled to characterize and localize their source, that can be explained as the pulsation activity of the primary component. The secondary, less massive component, is beyond the instability belt on H-R diagram and fulfills its Roche lobe. The accreting primary component pulsates in modes typical for the δ Scuti stars.

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 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 Study of Eclipsing Binary and Multiple Systems in OB Associations IV: Cas OB6 Member DN Cas

2016 ◽  
Vol 33 ◽  
Author(s):  
V. Bakış ◽  
H. Bakış ◽  
S. Bilir ◽  
Z. Eker
Keyword(s):  
Orbital Period ◽  
Early Type ◽  
Eccentric Orbit ◽  
Period Analysis ◽  
Multiple Systems ◽  
Spectroscopic Binary ◽  
Short Period ◽  
Synchronous Rotation ◽  
The Masses ◽  
Absolute Parameters

AbstractAn early-type, massive, short-period ($P_{\text{orb}}=2^d.310951$) eclipsing spectroscopic binary DN Cas has been re-visited with new spectral and photometric data. The masses and radii of the components have been obtained as $M_1=19.04\pm 0.07\,\text{M}_\odot$, $M_2=13.73\pm 0.05\,\text{M}_\odot$ and $R_1=7.22\pm 0.06\,\text{R}_\odot$, $R_2=5.79\pm 0.06\,\text{R}_\odot$, respectively. Both components present synchronous rotation ($V_{\text{rot}1}=160\,\text{km } \text{s}^{-1}$, $V_{\text{rot}2}=130\ \text{km} \,\text{s}^{-1}$) with their orbit. Orbital period analysis yielded a physically bound additional component in the system with a minimum mass of $M_3=0.88\,\text{M}_\odot$ orbiting in an eccentric orbit (e = 0.37 ± 0.2) with an orbital period of P12 = 42 ± 9 yr. High precision absolute parameters of the system allowed us to derive a distance to DN Cas as 1.7 ± 0.2 kpc which locates the system within the borders of the Cas OB6 association (d = 1.8 kpc). The space velocities and the age of DN Cas are in agreement with those of Cas OB6. The age of DN Cas (τ = 3–5 Myr) is found to be 1–2 Myr older than the embedded clusters (IC 1795, IC 1805, and IC 1848) in the Cas OB6 association, which implies a sequential star formation in the association.

scholarly journals The radius and the pulsation constant of the primary of Spica

1988 ◽  
Vol 123 ◽  
pp. 273-276
Author(s):  
M. Jerzykiewicz ◽  
C. Sterken
Keyword(s):  
Orbital Period ◽  
Primary Component ◽  
Light Variation ◽  
The Other ◽  
Period Term ◽  
Short Period ◽  
Short Period Term

In the late sixties, Spica (α Virginia, a 4.01454-day SB2 and interferometric binary, with a B1 IV primary component) was showing a light variation that consisted of two periodic terms. One term had the form of a double wave with the above-mentioned orbital period, the other was sinusoidal in shape and had a period equal to 0.1738 days. The double-wave term was clearly an ellipsoidal variation, caused by aspect changes of the tidally distorted primary, whereas the short-period term could only be explained as due to the primary's β Cephei-type pulsations. However, in 1972 these pulsations became undetectable.

scholarly journals KIC 4544587: An Eccentric, Short Period Binary with δ Scuti Pulsations and Tidally Excited Modes

2011 ◽  
Vol 7 (S282) ◽  
pp. 77-78
Author(s):  
Kelly Hambleton ◽  
Don Kurtz ◽  
Andrej Prša ◽  
Steven Bloemen ◽  
John Southworth
Keyword(s):  
Light Curve ◽  
Orbital Period ◽  
Main Sequence ◽  
Binary Star ◽  
Original Data ◽  
Primary Component ◽  
Apsidal Motion ◽  
Orbital Frequency ◽  
Short Period ◽  
Eclipsing Binary Star

AbstractKIC 4544587 is an eclipsing binary star with clear signs of apsidal motion and indications of tidal resonance. The primary component is an early A-type δ Scuti variable, with a temperature of 8270±250 K, whilst the secondary component is an early G-type main sequence star with a temperature of 6500±310 K. The orbital period of this system is 2.18911(1) d, with the light curve demonstrating a hump after secondary minimum due to distortion and reflection. The frequency spectrum of the residual data (the original data with the binary characteristics removed) contains both pressure (p) and gravity (g) modes. Eight of the g modes are precise multiples of the orbital frequency, to an accuracy greater than 3 σ. This is a signature of resonant excitation.

The Eclipsing Binary WX Eridani

1979 ◽  
Vol 46 ◽  
pp. 385
Author(s):  
M.B.K. Sarma ◽  
K.D. Abhankar
Keyword(s):  
Light Curve ◽  
Spectral Type ◽  
Orbital Period ◽  
Primary Component ◽  
Light Curves ◽  
Absorption Feature ◽  
Primary Star ◽  
Eclipsing Binary ◽  
The Times ◽  
Phase Angles

AbstractThe Algol-type eclipsing binary WX Eridani was observed on 21 nights on the 48-inch telescope of the Japal-Rangapur Observatory during 1973-75 in B and V colours. An improved period of P = 0.82327038 days was obtained from the analysis of the times of five primary minima. An absorption feature between phase angles 50-80, 100-130, 230-260 and 280-310 was present in the light curves. The analysis of the light curves indicated the eclipses to be grazing with primary to be transit and secondary, an occultation. Elements derived from the solution of the light curve using Russel-Merrill method are given. From comparison of the fractional radii with Roche lobes, it is concluded that none of the components have filled their respective lobes but the primary star seems to be evolving. The spectral type of the primary component was estimated to be F3 and is found to be pulsating with two periods equal to one-fifth and one-sixth of the orbital period.

RSCVn Stars in the Southern Hemisphere

1979 ◽  
Vol 46 ◽  
pp. 371-384 ◽  
Author(s):  
J.B. Hearnshaw
Keyword(s):  
Light Curve ◽  
Southern Hemisphere ◽  
Orbital Period ◽  
Binary Stars ◽  
Small Amplitude ◽  
Light Variation ◽  
Orbital Phase

RSCVn stars are fully detached binary stars which show intrinsic small amplitude (up to 0.3 amplitude peak-to-peak) light variations, as well as, in most of the known cases, eclipses. The spectra are F to G, IV to V for the hotter component and usually KOIV for the cooler. They are also characterised by abnormally strong H and K emission from the cooler star, or, occasionally, from both components. The orbital and light curve periods are in the range 1 day to 2 weeks. An interesting feature is the migration of the light variations to earlier orbital phase, as the light variation period is shorter than the orbital period by a few parts in 10+4to a few parts in 10+3.

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