- ID:
- ivo://CDS.VizieR/J/A+A/380/258
- Title:
- V light curve of AzV 73
- Short Name:
- J/A+A/380/258
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A CCD V light curve for the eclipsing binary star AzV 73 is presented. This new photometric observations are analysed together with previously published CCD I photometry from Udalski et al. (1998AcA....48..563U) and spectrographic data from Niemela & Bassino (1994ApJ...437..332N), by means of the Wilson-Devinney code. It is found that this system is semi-detached, with an orbital inclination of roughly 86{deg} and a separation of 42R_{sun}_. The sizes and masses are R_1_=11.53 +/-0.5R_{sun}_, M_1_=25.26+/-0.7M_{sun}_, and R_2_=15.46+/-0.4R_{sun}_, M_2_=21.96+/-0.8M_{sun}_ for the primary and secondary components, respectively.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/147/42
- Title:
- V light curves of EP Cep, ES Cep, and V369 Cep
- Short Name:
- J/AJ/147/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 188 is a good laboratory for studying the formation and evolution of W UMa type contact binaries due to its rich populations of them. We present a detailed photometric study of three short-period close binaries, EP Cep, ES Cep, and V369 Cep, in the old open cluster NGC 188 based on our two-set photometric observations. We discovered that both EP Cep and ES Cep are shallow-contact binaries with continuously decreasing periods. The difference is in their mass ratios. EP Cep has an extremely low-mass ratio, q=0.15, while ES Cep has a relatively high-mass ratio, q=0.69, indicating that they lie in different evolutionary stages. ES Cep is likely a newly formed contact binary via a Case A mass transfer, while EP Cep is an evolved system and may be on the oscillations caused by the combined effect of the thermal relaxation oscillation and the variable angular momentum loss. For another system, V369 Cep, we found that it is a primary-filling near-contact binary. Both the semidetached configuration and the continuous decrease in the orbital period indicate that it is undergoing a mass transfer from the primary component to the secondary one. This conclusion is in agreement with the excess luminosity seen in the light curves on the ingress of the secondary minimum produced by the impact of the mass transfer. All of the results suggest that V369 Cep is evolving into contact, and a shallow-contact high-mass ratio system similar to ES Cep will be formed. Then, it will evolve into a low-mass ratio contact binary just like EP Cep, and finally merge into a rapidly rotating single star.
- ID:
- ivo://CDS.VizieR/J/MNRAS/446/411
- Title:
- V lightcurves of J1407 from PROMPT-4 and ROAD
- Short Name:
- J/MNRAS/446/411
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The young (~16 Myr) pre-main-sequence star in Sco-Cen 1SWASP J140747.93-394542.6, hereafter referred to as J1407, underwent a deep eclipse in 2007 April, bracketed by several shallower eclipses in the surrounding 54d. This has been interpreted as the first detection of an eclipsing ring system circling a substellar object (dubbed J1407b). We report on a search for this companion with Sparse Aperture Mask imaging and direct imaging with both the UT4 VLT and Keck telescopes. Radial velocity measurements of J1407 provide additional constraints on J1407b and on short period companions to the central star. Follow-up photometric monitoring using the Panchromatic Robotic Optical Monitoring and Polarimetry Telescopes (PROMPT)-4 and ROAD observatories during 2012-2014 has not yielded any additional eclipses. Large regions of mass-period space are ruled out for the companion. For circular orbits the companion period is constrained to the range 3.5-13.8 yr (a~2.2-5.6 au), and stellar masses (>80 M_Jup_) are ruled out at 3{sigma} significance over these periods. The complex ring system appears to occupy more than 0.15 of its Hill radius, much larger than its Roche radius and suggesting a ring structure in transition. Further, we demonstrate that the radial velocity of J1407 is consistent with membership in the Upper Cen-Lup subgroup of the Sco-Cen association, and constraints on the rotation period and projected rotational velocity of J1407 are consistent with a stellar inclination of i_*_~68{deg}+/-10{deg}.
- ID:
- ivo://CDS.VizieR/J/AJ/141/44
- Title:
- V396 Mon BVRI light curves
- Short Name:
- J/AJ/141/44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper analyzes the first obtained four-color light curves of V396 Mon using the 2003 version of the W-D code. It is confirmed that V396 Mon is a shallow W-type contact binary system with a mass ratio q=2.554(+/-0.004) and a degree of contact factor f=18.9%(+/-1.2%). A period investigation based on all available data shows that the period of the system includes a long-term decrease (dP/dt=-8.57x10^-8^days/yr) and an oscillation (A3=0.0160day, T3=42.4yr). They are caused by angular momentum loss and light-time effect, respectively. The suspect third body is possibly a small M-type star (about 0.31 solar mass).
- ID:
- ivo://CDS.VizieR/J/A+A/624/A88
- Title:
- V643 Ori differential light curves
- Short Name:
- J/A+A/624/A88
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- One of the greatest uncertainties in modelling the mass-exchange phases during the evolution of a binary system is the amount of mass and angular momentum that has been lost from the system. In order to constrain this problem, a favourable, evolved and detached real binary system is valuable as an example of the end result of this process. We study the 52-day post-mass-exchange eclipsing binary V643 Ori from complete uvby light curves and high-resolution spectra. V643 Ori is double-lined and shows total primary eclipses. The orbit is accurately circular and the rotation of both stars synchronised with the orbit, but the photometry from a single year (1993) shows signs of weak spot activity (0.02mag) around the primary eclipse. We determine accurate masses of 3.3 and 1.9M_{sun}_ from the spectroscopic orbit and solve the four light curves to determine radii of 16 and 21R_{sun}_, using the Wilson-Devinney photometric code. The rotational velocities from the cross-correlation profiles agree well with those computed from the known radii and orbital parameters. All observable parameters are thus very precisely determined, but the masses and radii of V643 Ori are incompatible with undisturbed post-main-sequence evolution. We have attempted to simulate the past evolutionary history of V643 Ori under both conservative and non-conservative Case B mass transfer scenarios. In the non-conservative case we varied the amounts of mass and angular momentum loss needed to arrive at the present masses in a circular 52-day orbit, keeping the two stars detached and synchronized as now observed, but without following the evolution of other stellar properties in any detail. Multiple possible solutions were found. Further attempts were made using both the BSE formalism and the binary MESA code in order to track stellar evolution more closely, and make use of the measured radii and temperatures as important additional constraints. Those efforts did not yield satisfactory solutions, possibly due to limitations in handling mass transfer in evolved stars such as these. We remain hopeful that future theoreticians can more fully model the system under realistic conditions.
- ID:
- ivo://CDS.VizieR/J/A+A/480/465
- Title:
- V505 Per BV light curves
- Short Name:
- J/A+A/480/465
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The orbit and fundamental physical parameters of the double-lined eclipsing binary V505 Per are derived by means of Echelle high-resolution and high S/N spectroscopy, and B, V photometry. In addition, effective temperatures, gravities, rotational velocities, and metallicities of both components are also obtained from atmospheric chi^2^ analysis, showing an excellent match with the results of the orbital solution.
- ID:
- ivo://CDS.VizieR/J/other/NewA/36.50
- Title:
- V873 Per BVR light curves
- Short Name:
- J/other/NewA/36.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a photometric study of a weak-contact binary V873 Per. New observations in BVR filter bands showed asymmetric light curves to be a negative type of the O'Connell effect, which can be described by magnetic activity of a cool spot on the more massive component. Our photometric solutions showed that V873 Per is a W-type with a mass ratio of q=2.504(+/-0.0029), confirming the results of Samec et al. (2009IBVS.5901....1S). The derived contact degree was found to be f=18.10%(+/-1.36%). Moreover, our analysis found the cyclic variation with the period of about 4yr that could be due to existence of the third companion in the system or the mechanism of magnetic activity cycle in the binary. While available data indicated that the long-term orbital period tends to be stable rather than decreasing.
- ID:
- ivo://CDS.VizieR/J/A+A/319/867
- Title:
- V436 Persei = 1 Persei byBV photometry
- Short Name:
- J/A+A/319/867
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Outline of a project aimed at testing the presence of rapid line-profile variations in the atmospheres of hot components of close binaries is presented and its first results are described. An analysis of new electronic spectra of the eclipsing binary V436 Per from three observatories and of photoelectric observations, obtained earlier by several authors, leads to a unique determination of all basic physical elements of this interesting object. The first practical application of a new method of spectral disentangling allowed us to obtain, for the first time, individual accurate line profiles of both binary components and to derive their rotational velocities and orbital radial-velocity curves. We also detected absorption sub-features travelling from blue to red accross the He I 6678 line profile, in a series of six spectra taken during one night. At least one of the components of V436 Per is, therefore, a new hot line-profile variable.
- ID:
- ivo://CDS.VizieR/J/A+A/408/611
- Title:
- V436 Persei UBV photometry
- Short Name:
- J/A+A/408/611
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An analysis of new spectroscopic and photoelectric UBV observations, satisfactorily covering the whole orbital period of V436 Per, together with existing data allowed us to improve the knowledge of the basic physical characteristics of the binary and its components. In several aspects, our new results differ from the findings of Paper I (Harmanec et al., 1997, Cat. <J/A+A/319/867>) of this series: In particular, we found that it is the star eclipsed in the secondary minimum which is slightly more massive and larger than the optical primary. We also conclude that the apsidal advance -- if present at all -- is much slower than that estimated in a previous study. The orbital period might be increasing by 0.28 s per year but also this finding is very uncertain and needs verification by future observations. It is encouraging to note that two completely independent sets of programs for light-curve solutions lead to identical results. A notable finding is that both binary components rotate with very similar -- if not identical -- rotational periods of 1.45d and 1.40d, much shorter than what would correspond to a 10.9d spin-orbit synchronization period at periastron. Rapid line-profile changes reported earlier could not be confirmed from new, dedicated series of high-resolution and S/N spectra.
- ID:
- ivo://CDS.VizieR/J/A+AS/133/7
- Title:
- V photometry of YY CMi
- Short Name:
- J/A+AS/133/7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New V photoelectric observations of the eclipsing system YY CMi, obtained at La Silla, Chile, and Merate Observatory, Italy, are presented. New times of minima and ephemeris based on our observations are also given. The V light curve was analysed by using the WD code to derive the geometrical and physical parameters of the system. Since no spectroscopic mass ratio is available, the q-search method was applied to yield the preliminary range of the mass ratio in order to search for the final solution. First the unspotted solution was carried out by using the unperturbed parts of the light curve and applying the DC program of the WD code. The solution was performed by assuming contact (mode 3) and semi-detached (mode 4) configuration, since no classification of the system is possible from the shape of the light curve. The solution in mode 4 does not lead to an acceptable model, since the secondary was found to be slightly overcontact. Therefore the contact solution was finally adopted. Moreover the light curve peculiarities (MaxII fainter than MaxI and excess of light around the phase 0.32) were explained by assuming a cool and a hot spot on the surface of the secondary (cooler) component. The degree of contact is very small (f=~3%) and the thermal contact is poor (T_1_-T_2_)=~650K. These results together with the high photometric mass ratio q=~0.89 indicate that YY CMi is very probably a system at the beginning or the end of the contact phase.
