New observations of DW Cnc: where is the 38 min signal?

ABSTRACT We present extensive radial velocity observations of the intermediate polar DW Cnc during its 2018–2019 low state. We show that the 86 min signal associated with the orbital period is strong in our radial velocity analysis, power spectrum search, and in our Doppler tomography. However, we find that the velocity modulation associated with the 70 min beat period and the 38 min spin cycle is dramatically weaker than that previously observed. We put forward two interpretations for this change. The first is that a sudden drop into a low state detected in 2018–2019 caused an episode of low mass transfer from the companion, thus inhibiting the lighthouse effect produced by the rebound emission. The second is that this is a consequence of a rare outburst detected in 2007 by Crawford et al. (2008). We find this post-outburst hypothesis to be less likely. If the first scenario is correct, we predict that DW Cnc will recover its intermediate polar characteristics. A new ephemeris is presented by combining Patterson et al. (2004) radial velocities with ours.

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X-ray and optical observations of BY Cam

International Astronomical Union Colloquium ◽

10.1017/s0252921100038665 ◽

1996 ◽

Vol 158 ◽

pp. 213-214 ◽

Cited By ~ 1

Author(s):

Gavin Ramsay ◽

Paul A. Mason

Keyword(s):

Power Spectrum ◽

Orbital Period ◽

White Dwarf ◽

Optical Observations ◽

Optical Data ◽

Spin Orbit ◽

Side Band ◽

X Ray ◽

Beat Period ◽

Spin Period

We present preliminary results of an analysis of X-ray and optical data of the asynchronous AM Her star BY Cam [1]. We use X-ray data from EXOSAT (0.1… 50 keV), Ginga (1.5… 50 keV) and ROSAT (0.1…2.0 keV) and optical data obtained during a 45-day campaign in 1994.There are 4 known periods: the orbital period (201.30 m), the spin period of the white dwarf (199.3303 m), a spin-orbit beat period (14.15 d) and a side-band period (197.4 m). The detection of this side-band period lends credence to the theory of [2], who suggest that for a stream accreting, diskless, magnetic CV a frequency, f = 2ωspin − Ωorb (=197.399 m), will appear as a strong spike in the power spectrum for certain systems. Wu & Mason (this volume) discuss a competing model where Pspin = 197.4 m.

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Time-Resolved Spectroscopy and Doppler Tomography of UX UMa

International Astronomical Union Colloquium ◽

10.1017/s025292110015314x ◽

2004 ◽

Vol 194 ◽

pp. 270-270 ◽

Cited By ~ 1

Author(s):

V. F. Suleimanov ◽

V. V. Neustroev ◽

N. V. Borisov ◽

I. S. Fioktistova

Keyword(s):

Radial Velocity ◽

Emission Line ◽

Orbital Period ◽

Velocity Curve ◽

Cataclysmic Variable ◽

Radial Velocity Curve ◽

Doppler Tomography ◽

Time Resolved ◽

Time Resolved Spectroscopy ◽

Medium Resolution

Medium resolution spectroscopy of nova-like cataclysmic variable UX UMA was performed using the 6-m telescope SAO RAS in April 1999. Obtained spectra cover the total orbital period including eclipse phases and allow us to reproduce the radial velocity curve. The radial-velocity variations of the Hβ emission line are found to have semi-amplitude of about 100 km/s.

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Influence of the initial orbital period and accretion efficiency on the low-mass binary evolution

Serbian Astronomical Journal ◽

10.2298/saj2102025p ◽

2021 ◽

pp. 25-30

Author(s):

J. Petrovic

Keyword(s):

Mass Transfer ◽

Orbital Period ◽

White Dwarf ◽

Binary Systems ◽

Evolutionary Models ◽

Stable Case ◽

Long Period ◽

Low Mass ◽

Orbital Periods ◽

Binary Evolution

This paper presents detailed evolutionary models of low-mass binary systems (1.25 + 1 M?) with initial orbital periods of 10, 50 and 100 days and accretion efficiency of 10%, 20%, 50%, and a conservative assumption. All models are calculated with the MESA (Modules for Experiments in Stellar Astrophysics) evolutionary code. We show that such binary systems can evolve via a stable Case B mass transfer into long period helium white dwarf systems.

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Period dependent variations of the shell spectrum of V923 AQL

Symposium - International Astronomical Union ◽

10.1017/s0074180900215386 ◽

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).

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ASASSN-14ho: Longest-period dwarf nova with multiple rebrightenings

Publications of the Astronomical Society of Japan ◽

10.1093/pasj/psz135 ◽

2020 ◽

Vol 72 (1) ◽

Author(s):

Taichi Kato

Keyword(s):

Mass Transfer ◽

Radial Velocity ◽

Accretion Disks ◽

Orbital Period ◽

Formal Solution ◽

Dwarf Novae ◽

X Ray ◽

Dwarf Nova ◽

Orbital Periods ◽

The Stability

Abstract The post-outburst rebrightening phenomenon in dwarf novae and X-ray novae is still one of the most challenging subjects for theories of accretion disks. It has been widely recognized that post-outburst rebrightenings are a key feature of WZ Sge-type dwarf novae, which predominantly have short (≲0.06 d) orbital periods. The author found four post-outburst rebrightenings in ASASSN-14ho during its 2014 outburst, whose orbital period was recently measured to be exceptionally long [0.24315(10) d]. Using the formal solution of the radial velocity study in the literature, this paper discusses the possibility that this object could be an SU UMa-type dwarf nova near the stability border of the 3 : 1 resonance, despite its exceptionally long orbital period. Such objects are considered to be produced if mass transfer occurs after the secondary has undergone significant nuclear evolution, and they may be hidden in a significant number of dwarf novae showing multiple post-outburst rebrightenings.

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Light Curves Analysis and Period Study of Two Eclipsing Binaries UZ Lyr and BR Cyg

Research in Astronomy and Astrophysics ◽

10.1088/1674-4527/ac3e5f ◽

2021 ◽

Author(s):

Kazem Yoosefi Roobiat ◽

Reza Pazhouhesh

Keyword(s):

Mass Transfer ◽

Radial Velocity ◽

Orbital Period ◽

Binary Systems ◽

Eclipsing Binaries ◽

Light Curves ◽

Secondary Component ◽

Physical Parameters ◽

Time Effects ◽

First Time

Abstract Two eclipsing binary systems UZ Lyr and BR Cyg are the semi-detached types whose secondary component fill its Roche lobe. Although radial velocity and light curves of these systems have already been investigated separately, both radial velocity and light curves of them are analyzed simultaneously for the first time in the present study . Also, the orbital period changes of these systems are studied. Our results show that the mass transfer between components have negligible effects on the orbital period changes of these systems, but two light-time effects are the reasons of the periodic behavior of the O-C curve for UZ Lyr. We could not remark more information about orbital period changes for BR Cyg, but we find a new orbital period for it. By radial velocity and light curves analysis we find a clod spot on the secondary components of BR Cyg. The new geometrical and physical parameters of both systems are obtained and their positions on H-R diagram demonstrated.

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TOI-222: a single-transit TESS candidate revealed to be a 34-d eclipsing binary with CORALIE, EulerCam, and NGTS

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz3545 ◽

2019 ◽

Vol 492 (2) ◽

pp. 1761-1769 ◽

Cited By ~ 12

Author(s):

Monika Lendl ◽

François Bouchy ◽

Samuel Gill ◽

Louise D Nielsen ◽

Oliver Turner ◽

...

Keyword(s):

Radial Velocity ◽

High Precision ◽

Orbital Period ◽

Mass Star ◽

Mass Determination ◽

Velocity Measurements ◽

Eclipsing Binary ◽

Photometric Detection ◽

Long Period ◽

Low Mass

ABSTRACT We report the period, eccentricity, and mass determination for the Transiting Exoplanet Survey Satellite (TESS) single-transit event candidate TOI-222, which displayed a single 3000 ppm transit in the TESS 2-min cadence data from Sector 2. We determine the orbital period via radial velocity measurements (P = 33.9 d), which allowed for ground-based photometric detection of two subsequent transits. Our data show that the companion to TOI-222 is a low-mass star, with a radius of $0.18_{-0.10}^{+0.39}$ R⊙ and a mass of 0.23 ± 0.01 M⊙. This discovery showcases the ability to efficiently discover long-period systems from TESS single-transit events using a combination of radial velocity monitoring coupled with high-precision ground-based photometry.

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Exoplanet mass estimation for a sample of targets for the Ariel mission

Experimental Astronomy ◽

10.1007/s10686-021-09758-0 ◽

2021 ◽

Author(s):

J. R. Barnes ◽

C. A. Haswell

Keyword(s):

Radial Velocity ◽

Input Parameter ◽

Noise Sources ◽

Time Commitment ◽

Low Mass ◽

Time Required ◽

Fixed Input ◽

The Impact ◽

Quadrature Sampling

AbstractAriel’s ambitious goal to survey a quarter of known exoplanets will transform our knowledge of planetary atmospheres. Masses measured directly with the radial velocity technique are essential for well determined planetary bulk properties. Radial velocity masses will provide important checks of masses derived from atmospheric fits or alternatively can be treated as a fixed input parameter to reduce possible degeneracies in atmospheric retrievals. We quantify the impact of stellar activity on planet mass recovery for the Ariel mission sample using Sun-like spot models scaled for active stars combined with other noise sources. Planets with necessarily well-determined ephemerides will be selected for characterisation with Ariel. With this prior requirement, we simulate the derived planet mass precision as a function of the number of observations for a prospective sample of Ariel targets. We find that quadrature sampling can significantly reduce the time commitment required for follow-up RVs, and is most effective when the planetary RV signature is larger than the RV noise. For a typical radial velocity instrument operating on a 4 m class telescope and achieving 1 m s−1 precision, between ~17% and ~ 37% of the time commitment is spent on the 7% of planets with mass Mp < 10 M⊕. In many low activity cases, the time required is limited by asteroseismic and photon noise. For low mass or faint systems, we can recover masses with the same precision up to ~3 times more quickly with an instrumental precision of ~10 cm s−1.

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Search for intermittent X-ray pulsations from neutron stars in low-mass X-ray binaries

Publications of the Astronomical Society of Australia ◽

10.1017/pasa.2021.6 ◽

2021 ◽

Vol 38 ◽

Author(s):

Yunus Emre Bahar ◽

Manoneeta Chakraborty ◽

Ersin Göğüş

Keyword(s):

Neutron Stars ◽

Orbital Period ◽

Oscillation Frequency ◽

Orbital Motion ◽

X Rays ◽

X Ray ◽

Second Stage ◽

Corrected Data ◽

Low Mass ◽

X Ray Binaries

Abstract We present the results of our extensive binary orbital motion corrected pulsation search for 13 low-mass X-ray binaries. These selected sources exhibit burst oscillations in X-rays with frequencies ranging from 45 to 1 122 Hz and have a binary orbital period varying from 2.1 to 18.9 h. We first determined episodes that contain weak pulsations around the burst oscillation frequency by searching all archival Rossi X-ray Timing Explorer data of these sources. Then, we applied Doppler corrections to these pulsation episodes to discard the smearing effect of the binary orbital motion and searched for recovered pulsations at the second stage. Here we report 75 pulsation episodes that contain weak but coherent pulsations around the burst oscillation frequency. Furthermore, we report eight new episodes that show relatively strong pulsations in the binary orbital motion corrected data.

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