- ID:
- ivo://CDS.VizieR/J/A+A/615/A131
- Title:
- R CMa radial velocity curves
- Short Name:
- J/A+A/615/A131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- R Canis Majoris is the prototype of a small group of Algol-type stars showing short orbital periods and low mass ratios. A previous detection of short-term oscillations in its light curve has not yet been confirmed. We investigate a new time series of high-resolution spectra with the aim to derive improved stellar and system parameters, to search for the possible impact of a third component in the observed spectra, to look for indications of activity in the Algol system, and to search for short-term variations in radial velocities. We disentangled the composite spectra into the spectra of the binary components. Then we analysed the resulting high signal-to-noise spectra of both stars. Using a newly developed program code based on an improved method of least-squares deconvolution, we were able to determine the radial velocities of both components also during primary eclipse. This allowed us to develop a better model of the system including the Rossiter-McLaughlin effect and to derive improved orbital parameters. Combining the results with those from spectrum analysis, we obtain accurate stellar and system parameters. We further deduce at least one oscillation frequency of 21.38c/d. It could be detected during primary eclipses only and confirms a previous photometric finding. Results point to an amplitude amplification of non-radial pulsation modes due to the eclipse mapping effect. The presence of a HeI line in the spectra indicates mass transfer in the R CMa system. Calculations of its Roche geometry give evidence that the cool secondary component may fill its Roche lobe. No evidence of a third body in the system could be found in the observed spectra.
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- ID:
- ivo://CDS.VizieR/J/A+A/600/A55
- Title:
- Refined Analysis of T-Cyg1-12664
- Short Name:
- J/A+A/600/A55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The observational mass-radius relation of main sequence stars with masses between ~0.3 and 1.0M_{sun}_ reveals deviations between the stellar radii predicted by models and the observed radii of stars in detached binaries. We generate an accurate physical model of the low-mass eclipsing binary T-Cyg1-12664 in the Kepler mission field to measure the physical parameters of its components and to compare them with the prediction of theoretical stellar evolution models. We analyze the Kepler mission light curve of T-Cyg1-12664 to accurately measure the times and phases of the primary and secondary eclipse. In addition, we measure the rotational period of the primary component by analyzing the out-of-eclipse oscillations that are due to spots. We accurately constrain the effective temperature of the system using ground-based absolute photometry in B, V, R_C_, and I_C_. We also obtain and analyze VR_C_I_C_ differential light curves to measure the eccentricity and the orbital inclination of the system, and a precise Teff ratio. From the joint analysis of new radial velocities and those in the literature we measure the individual masses of the stars. Finally, we use the PHOEBE code to generate a physical model of the system.
- ID:
- ivo://CDS.VizieR/J/A+A/398/239
- Title:
- RI differential photometry of CU Cnc
- Short Name:
- J/A+A/398/239
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric observations in the R and I bands of the detached M-type double-lined eclipsing binary CU Cnc have been acquired and analysed. The photometric elements obtained from the analysis of the light curves have been combined with an existing spectroscopic solution to yield high-precision (errors<2%) absolute dimensions: M_A_=0.4333+/-0.0017M_{sun}_, M_B_=0.3980+/-0.0014M_{sun}_, R_A_=0.4317+/-0.0052R_{sun}_, and R_B_=0.3908+/-0.0094R_{sun}_. The mean effective temperature of the system has been estimated to be Teff=3140+/-150K by comparing multi-band photometry with synthetic colors computed from model atmospheres. Additionally, we have been able to obtain an estimate for the age (~320Myr) and chemical composition ([Fe/H]~0.0) of the binary system through its membership of the Castor moving group.
- ID:
- ivo://CDS.VizieR/J/A+A/439/433
- Title:
- RIJ photometry of stars around PSR B1718-19
- Short Name:
- J/A+A/439/433
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In our paper we present VLT-observations in R, I and J of the candidate companion of PSR B1718-19, and also make use of HST observations in F702W, previously presented in Van Kerkwijk et al., 2000ApJ...529..428V. We make available online our astrometry and photometry including error-bars. The field-size is approximately 34x34 arcsec (F702W), 80x80 arcsec (R & I), and 89x89 arcsec (J).
- ID:
- ivo://CDS.VizieR/J/AJ/119/1901
- Title:
- ROTSE all-sky surveys for variable stars
- Short Name:
- J/AJ/119/1901
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Robotic Optical Transient Search Experiment I (ROTSE-I) experiment has generated CCD photometry for the entire northern sky in two epochs nightly since 1998 March. These sky patrol data are a powerful resource for studies of astrophysical transients. As a demonstration project, we present first results of a search for periodic variable stars derived from ROTSE-I observations. Variable identification, period determination, and type classification are conducted via automatic algorithms. In a set of nine ROTSE-I sky patrol fields covering roughly 2000 deg^2^, we identify 1781 periodic variable stars with mean magnitudes between m_v_ = 10.0 and m_v_ = 15.5. About 90% of these objects are newly identified as variable. Examples of many familiar types are presented. All classifications for this study have been manually confirmed. The selection criteria for this analysis have been conservatively defined and are known to be biased against some variable classes. This preliminary study includes only 5.6% of the total ROTSE-I sky coverage, suggesting that the full ROTSE-I variable catalog will include more than 32,000 periodic variable stars.
- ID:
- ivo://CDS.VizieR/J/PASP/125/17
- Title:
- RU Eri UBV differential light curves
- Short Name:
- J/PASP/125/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- RU Eri is a near-contact eclipsing binary (V~9.24mag) with a 0.632-day orbital period. The Wilson-Devinney program is used to simultaneously solve new UBV light curves obtained between 1973 and 1981 at the Fernbank Science Center Observatory, together with existing single-lined radial velocity measurements. Light and velocity solution parameters, orbital elements, and absolute dimensions are presented. A period of 0.632198836+/-0.000000046d is found.
- ID:
- ivo://CDS.VizieR/J/other/RAA/9.1035
- Title:
- RV light curves of 1RXS J201607.0+251645
- Short Name:
- J/other/RAA/9.10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 1RXS J201607.0+251645 is identified as an eclipsing binary. We present preliminary observations in the V band with the 0.6-m telescope for three years and extensive observations in the V and R bands with the 0.8-m telescope for six nights, respectively. The light curve of the system is EB type. Five light minimum times were obtained and the orbital period of 0.388058d(+/-0.00044d) is determined.
- ID:
- ivo://CDS.VizieR/J/ApJ/836/177
- Title:
- RVs and R-band obs. of the EB* V541 Cyg
- Short Name:
- J/ApJ/836/177
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report new spectroscopic and photometric observations of the main-sequence, detached, eccentric, double-lined eclipsing binary V541Cyg (P=15.34d, e=0.468). Using these observations together with existing measurements, we determine the component masses and radii to better than 1% precision: M_1_=2.335_-0.013_^+0.017^M_{sun}_, M_2_=2.260_-0.013_^+0.016^M_{sun}_, R_1_=1.859_-0.009_^+0.012^R_{sun}_, and R_2_=1.808_-0.013_^+0.015^R_{sun}_. The nearly identical B9.5 stars have estimated effective temperatures of 10650+/-200K and 10350+/-200K. A comparison of these properties with current stellar evolution models shows excellent agreement at an age of about 190Myr and [Fe/H]~-0.18. Both components are found to be rotating at the pseudo-synchronous rate. The system displays a slow periastron advance that is dominated by general relativity (GR), and has previously been claimed to be slower than predicted by theory. Our new measurement, dot{omega}=0.859_-0.017_^+0.042^deg/century, has an 88% contribution from GR and agrees with the expected rate within the uncertainties. We also clarify the use of the gravity darkening coefficients in the light-curve fitting Eclipsing Binary Orbit Program (EBOP), a version of which we use here.
- ID:
- ivo://CDS.VizieR/J/A+A/374/638
- Title:
- RY Sct UBVR photometry
- Short Name:
- J/A+A/374/638
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The present study deals with the problem of the estimation of the orbital and physical parameters for the EB-type eclipsing binary RY Sct, based on the interpretation of new photometric U B V R observations. The light curves obtained at the Maidanak Observatory during 1979-94 show a slight asymmetry around the secondary minima and a small difference in the height of the successive maxima. The light curves are analysed in the framework of the Roche computer model (Djurasevic, 1992Ap&SS.196..241D) by applying the inverse-problem method (Djurasevic, 1992Ap&SS.197...17D) based on Marquardt's (1963, J. Soc. Ind. Appl. Math. 11(2), 431) algorithm. The analysis shows that RY Sct system is in an overcontact configuration (f_over_~33%) with q=m_2_/m_1_=m_cool_/m_hot_=3.3 and i~84.3{deg}, generating total-annular eclipses. The basic parameters of the system and of the active region are estimated for all individual U, B, V and R light curves. Our results suggested a mass exchange between the components and mass loss through the outer Lagrangian point L_3_. This could be taken as a possible mechanism in the formation of the circumstellar envelope of toroidal form lying in the orbital plane of the system.
- ID:
- ivo://CDS.VizieR/J/AJ/116/1447
- Title:
- RZ Cas JK light curves
- Short Name:
- J/AJ/116/1447
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Light curves of the Algol-type binary system, RZ Cassiopeiae, in the near-IR wavelengths J and K are obtained for the first time. The light curves are analyzed using the Wilson-Devinney model. UBV light curves of RZ Cas obtained by Chambliss are also reanalyzed using the same program. In the J and K bands, the bolometric albedo of the secondary of RZ Cas exhibited values above 0.7, whereas the theoretically expected value for such a star is 0.5. Also, the values of the secondary temperature derived from the J and K light curves are found to be less than that derived from our analysis of the optical light curves as well as from the previous studies in the optical photometric bands. We have attempted to model these effects with a dark spot on the secondary of RZ Cas. The J-band light curve gave a better fit with a cool dark spot on the secondary. Another possible reason for the above mentioned effects is a gas stream from the lobe-filling secondary to the primary star. The magnitudes and colors of the individual components are derived from the observed light curves and the light contributions from the stars derived from the light curve analysis. The primary is found to be an A3 V star as observed by previous investigators. The secondary is classified as K0K4 IV from the derived colors. Seven epochs of primary minima and 3 epochs of secondary minima are obtained from the observations. Because of the increased depths of the secondary eclipse in the infrared bands, the moments of minima are calculated with nearly the same accuracy as that of the primary minima. All the secondary minima are found to occur at phase 0.5. None of the observed primary minima are flat as found by many observers before at optical wavelengths. The colors of the system at the minima obtained by us confirm that the system is partially eclipsing.
