- ID:
- ivo://CDS.VizieR/J/A+A/341/121
- Title:
- Visual binary orbits and masses
- Short Name:
- J/A+A/341/121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The paper gives orbits and masses for some 200 nearby visual binaries, as derived from combining ground-based and Hipparcos data. Table 6 gives identifications and notes, and points to the detailed data in Table 1 (short-P systems with mass-ratio from the Hipparcos observations), Table 3 (mass-uncertainty below 10%) or Table 4 (mass-uncertainty above 10%).
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- ID:
- ivo://CDS.VizieR/J/A+AS/132/253
- Title:
- 9 visual double stars orbital elements
- Short Name:
- J/A+AS/132/253
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Orbital elements and ephemerides for 9 visual double stars are given.
- ID:
- ivo://CDS.VizieR/J/AJ/148/38
- Title:
- WIYN open cluster study. LX. RV survey of NGC 6819
- Short Name:
- J/AJ/148/38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the current state of the WOCS radial-velocity (RV) survey for the rich open cluster NGC 6819 (2.5Gyr) including 93 spectroscopic binary orbits with periods ranging from 1.5 to 8000days. These results are the product of our ongoing RV survey of NGC 6819 using the Hydra Multi-Object Spectrograph on the WIYN 3.5m telescope. We also include a detailed analysis of multiple prior sets of optical photometry for NGC 6819. Within a 1{deg} field of view, our stellar sample includes the giant branch, the red clump, and blue straggler candidates, and extends to almost 2 mag below the main sequence (MS) turnoff. For each star observed in our survey we present all RV measurements, the average RV, and velocity variability information. Additionally, we discuss notable binaries from our sample, including eclipsing binaries (WOCS 23009, WOCS 24009, and WOCS 40007), stars noted in Kepler asteroseismology studies (WOCS 4008, WOCS 7009, and WOCS 8007), and potential descendants of past blue stragglers (WOCS 1006 and WOCS 6002). We find the incompleteness-corrected binary fraction for all MS binaries with periods less than 10^4^days to be 22%+/-3% and a tidal circularization period of 6.2^+1.1^_-1.1_days for NGC 6819.
- ID:
- ivo://CDS.VizieR/J/MNRAS/373/1483
- Title:
- W UMa type and CAB stars dynamical evolution
- Short Name:
- J/MNRAS/373/1483
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Orbital angular momentum (OAM, Jo), systemic mass (M) and orbital period (P) distributions of chromospherically active binaries (CAB) and W Ursae Majoris (W UMa) systems were investigated. The diagrams of and logJo-logP, logM-logP and logJo-logM were formed from 119 CAB and 102 W UMa stars. The log Jo-logM diagram is found to be most meaningful in demonstrating dynamical evolution of binary star orbits. A slightly curved borderline (contact border) separating the detached and the contact systems was discovered on the logJo-logM diagram. Since the orbital size (a) and period (P) of binaries are determined by their current Jo, M and mass ratio, q, the rates of OAM loss (dlogJo/dt) and mass loss (dlogM/dt) are primary parameters to determine the direction and the speed of the dynamical evolution. A detached system becomes a contact system if its own dynamical evolution enables it to pass the contact border on the logJo-logM diagram. The evolution of q for a mass-losing detached system is unknown unless the mass-loss rate for each component is known. Assuming q is constant in the first approximation and using the mean decreasing rates of Jo and M from the kinematical ages of CAB stars, it has been predicted that 11, 23 and 39 per cent of current CAB stars would transform to W UMa systems if their nuclear evolution permits them to live 2, 4 and 6Gyr, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/645/L6
- Title:
- zet01 Ret and zet02 activity indexes
- Short Name:
- J/A+A/645/L6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We explore if the star zet02 Ret, which belongs to a binary system, is in (or going to) a state similar to the MM. To do so, we have collected more than 430 spectra acquired between 2000 and 2019 with the HARPS, REOSC, UVES, and FEROS spectrographs. We performed a detailed long-term activity study of both components using the Mount Wilson index, which is obtained from the Ca II H&K lines. To search for signs of an activity cycle, we analyzed the resulting time-series with the Generalized Lomb-Scargle and CLEAN periodograms. Our spectroscopic analysis shows a high activity level for zet01 Ret and a significant decrease in the magnetic activity cycle amplitude of zet02 Ret. By analogy with the scenario that proposes a weak solar cycle during the MM, we suggest that activity signatures showed by zet02 Ret, i.e., a very low activity level when compared to its stellar companion, a notably decreasing amplitude (~47%), and a cyclic behaviour, are possible evidence that this star could be in a MM state. It is, to our knowledge, the first MM candidate star detected through a highly discrepant activity behaviour in a binary system.
