- ID:
- ivo://CDS.VizieR/J/A+A/502/253
- Title:
- V636 Cen radial velocities curves
- Short Name:
- J/A+A/502/253
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The influence of stellar activity on the fundamental properties of stars around and below 1M_{sun}_ is not well understood. Accurate mass, radius, and abundance determinations from solar-type binaries exhibiting various levels of activity are needed for a better insight into the structure and evolution of these stars. We aim to determine absolute dimensions and abundances for the solar-type detached eclipsing binary V636Cen, and to perform a detailed comparison with results from recent stellar evolutionary models. uvby light curves and uvby{beta} standard photometry were obtained with the Stroemgren Automatic Telescope, radial velocity observations with the CORAVEL spectrometer, and high-resolution spectra with the FEROS spectrograph, all at ESO, La Silla. State-of-the-art methods were applied for the photometric and spectroscopic analyses.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AN/332/616
- Title:
- V444 Cyg BV differential light curves
- Short Name:
- J/AN/332/616
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric and spectroscopic characteristics of the WN5+O6 binary system, V444 Cyg, were studied. The Wilson-Devinney (WD) analysis, using new BV observations carried out at the Ankara University Observatory, revealed the masses, radii, and temperatures of the components of the system as M_WR_=10.64M_{sun}_, M_O_=24.68M_{sun}_, R_WR_=7.19R_{sun}_, R_O_=6.85R_{sun}_, T_WR_=31000K, and T_O_=40000K, respectively. It was found that both components had a full spherical geometry, whereas the circumstellar envelope of the WR component had an asymmetric structure. The O-C analysis of the system revealed a period lengthening of 0.139+/-0.018s/yr, implying a mass loss rate of (6.76+/-0.39)x10^-6^M_{sun}/yr for the WR component. Moreover, 106 IUE-NEWSIPS spectra were obtained from NASA's IUE archive for line identification and determination of line profile variability with phase, wind velocities and variability in continuum fluxes. The integrated continuum flux level (between 1200-2000{AA}) showed a mild and regular increase from orbital phase 0.00 up to 0.50 and then a decrease in the same way back to phase 0.00. This is evaluated as the O component making a constant and regular contribution to the system's UV light as the dominant source. The CIV line, originating in the circumstellar envelope, had the highest velocity while N IV line, originating in deeper layers of the envelope, had the lowest velocity. The average radial velocity calculated by using the CIV line (wind velocity) was found as 2326km/s.
- ID:
- ivo://CDS.VizieR/J/other/NewA/31.32
- Title:
- V729 Cyg UBVRI light curves
- Short Name:
- J/other/NewA/31.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present multicolor photometry of the massive interacting close binary system V729 Cyg. The light variations of V729 Cyg were observed in the Bessel U, B, V, R and I bands over 65 nights between August 2010 and October 2011.
- ID:
- ivo://CDS.VizieR/J/other/NewA/53.1
- Title:
- V2480 Cyg V and R light curves
- Short Name:
- J/other/NewA/53.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the photometric analysis of the detached eclipsing binary V2480 Cyg. After taking the photometric data, the light curve was analyzed in PHOEBE software, which uses the Wilson-Devinney code. Due to the observed O'Connell (1951PRCO....2...85O) effect in light curve, we introduce a spotted model with 3 spots on the components, and the exact parameters of the system have been achieved. The main parameters of the system were calculated as about q_ptm_=1.7, T_eff1_=8075K and T_eff2_=3829K.
- ID:
- ivo://CDS.VizieR/J/AJ/151/66
- Title:
- Velocities of WOCS 24009 and WOCS 40007 in NGC 6819
- Short Name:
- J/AJ/151/66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As part of our study of the old (~2.5Gyr) open cluster NGC 6819 in the Kepler field, we present photometric (Kepler and ground-based BVR_C_I_C_) and spectroscopic observations of the detached eclipsing binary WOCS 24009 (Auner 665; KIC5023948) with a short orbital period of 3.6 days. WOCS 24009 is a triple-lined system, and we verify that the brightest star is physically orbiting the eclipsing binary using radial velocities and eclipse timing variations. The eclipsing binary components have masses M_B_=1.090+/-0.010M_{sun}_ and M_C_=1.075+/-0.013M_{sun}_, and radii R_B_=1.099+/-0.006+/-0.005R_{sun}_and R_C_=1.069+/-0.006+/-0.013R_{sun}_. The bright non-eclipsing star resides at the cluster turnoff, and ultimately its mass will directly constrain the turnoff mass: our preliminary determination is M_A_=1.251+/-0.057M_{sun}_. A careful examination of the light curves indicates that the fainter star in the eclipsing binary undergoes a very brief period of total eclipse, which enables us to precisely decompose the light of the three stars and place them in the color-magnitude diagram (CMD). We also present improved analysis of two previously discussed detached eclipsing stars in NGC6819 (WOCS40007 and WOCS23009) en route to a combined determination of the cluster's distance modulus (m-M)_V_=12.38+/-0.04. Because this paper significantly increases the number of measured stars in the cluster, we can better constrain the age of the CMD to be 2.21+/-0.10+/-0.20Gyr. Additionally, using all measured eclipsing binary star masses and radii, we constrain the age to 2.38+/-0.05+/-0.22Gyr. The quoted uncertainties are estimates of measurement and systematic uncertainties (due to model physics differences and metal content), respectively.
- ID:
- ivo://CDS.VizieR/J/AJ/133/2669
- Title:
- Velocity and H{alpha} width of 22 Vul
- Short Name:
- J/AJ/133/2669
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 22 Vul system is important for studying the winds and chromospheres of cool evolved stars because the G4 I component is rotating rapidly and probably faster than synchronously. We discuss the system's physical properties in the context of a wide range of constraints on them and propose values that may be marginally better than previous ones. We use H{alpha} spectroscopy to assess the variability of the cool star's wind, and archival IUE observations to measure variation of density in the wind and rotation of the chromosphere.
- ID:
- ivo://CDS.VizieR/J/AJ/130/2838
- Title:
- Velocity and light curves of RW Lac
- Short Name:
- J/AJ/130/2838
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 3004 differential observations in the V bandpass measured by a robotic telescope, as well as 36 pairs of radial velocities from high-resolution spectroscopic observations, of the detached, eccentric, EA-type, 10.37day period, double-lined eclipsing binary star RW Lac.
- ID:
- ivo://CDS.VizieR/J/A+A/537/A117
- Title:
- Velocity curves of SW CMa and HW CMa
- Short Name:
- J/A+A/537/A117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate physical properties of eclipsing stars provide important constraints on models of stellar structure and evolution, especially when combined with spectroscopic information on their chemical composition. Empirical calibrations of the data also lead to accurate mass and radius estimates for exoplanet host stars. Finally, accurate data for unusual stellar subtypes, such as Am stars, also help to unravel the cause(s) of their peculiarities. We aim to determine the masses, radii, effective temperatures, detailed chemical composition and rotational speeds for the Am-type eclipsing binaries SWCMa (A4-5m) and HWCMa (A6m) and compare them with similar normal stars.
- ID:
- ivo://CDS.VizieR/J/A+A/625/A150
- Title:
- 10 very-low-mass stars photometry
- Short Name:
- J/A+A/625/A150
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Measurements of the physical properties of stars at the lower end of the main sequence are scarce. In this context we report masses, radii and surface gravities of ten very-low-mass stars in eclipsing binary systems, with orbital periods of the order of several days. The objects probe the stellar mass-radius relation in the fully convective regime, M*<0.35M_{sun}_, down to the hydrogen burning mass-limit, M_HB_~0.07M_{sun}_. The stars were detected by the WASP survey for transiting extra-solar planets, as low-mass, eclipsing companions orbiting more massive, F- and G-type host stars. We use eclipse observations of the host stars, performed with the TRAPPIST, Leonhard Euler and SPECULOOS telescopes, and radial velocities of the host stars obtained with the CORALIE spectrograph, to determine the physical properties of the low-mass companions. Surface gravities of the low-mass companions are derived from the eclipse and orbital parameters of each system. Spectroscopic measurements of the host star effective temperature and metallicity are used to infer the host star mass and age from stellar evolution models for solar-type stars. Masses and radii of the low-mass companions are then derived from the eclipse and orbital parameters of the binary systems. The objects are compared to stellar evolution models for low-mass stars, to test for an effect of the stellar metallicity and orbital period on the radius of low-mass stars in close binary systems. Measurements are found to be in good agreement with stellar evolution models; a systematic inflation of the radius of low-mass stars with respect to model predictions is limited to 1.6+/-1.2%, in the fully convective low-mass regime. The sample of ten objects indicates a scaling of the radius of low-mass stars with the host star metallicity. No correlation between stellar radii and the orbital periods of the binary systems is determined. A combined analysis with thirteen comparable objects from the literature is consistent with this result.
- ID:
- ivo://CDS.VizieR/J/other/NewA/48.58
- Title:
- V1044 Her VR differential photometry
- Short Name:
- J/other/NewA/48.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new CCD photometric observations of V1044 Her obtained on May 22, 23 and 24, 2015. From our data, we derived five new light curve minimum times. Combining our new results with previously available CCD light minimum times, we derived an updated ephemeris and discovered that the period of this binary system exhibits an oscillation. The cyclic variation may be caused by the light-time effect via the presence of a third body or magnetic activity cycle. We calculated the corresponding period of the third body to be 14.1+/-1.4 years or magnetic cycle to be 12.2+/-0.7 years. We analyzed our new asymmetric light curves to obtain photometric solutions and starspot parameters using the Wilson and Devinney program. The final results show that V1044 Her is a contact binary system with a degree of contact factor f=3.220(+/-0.002)%.
