- ID:
- ivo://CDS.VizieR/J/AJ/131/3008
- Title:
- Double star speckle measures
- Short Name:
- J/AJ/131/3008
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 549 observations of 181 primarily southern binary stars. Of these, 32 are high-quality nondetections, meaning that, if binary, the system had a separation below the diffraction limit at the time of the observation, and relative astrometry is presented for the remaining 517 observations. In addition, a magnitude difference measure is reported in 312 cases in which the observation was judged to be of sufficient quality to have little decorrelation of the speckle pattern of the secondary relative to the primary star. These data were obtained from speckle observations taken at the Lowell-Tololo 0.6m telescope at Cerro Tololo Inter-American Observatory using a fast-readout CCD detector during 2001 November.
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- ID:
- ivo://CDS.VizieR/J/AJ/131/1000
- Title:
- Double star speckle measures
- Short Name:
- J/AJ/131/1000
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Position angle and separation measures of 482 primarily southern binary stars are presented. These were obtained from speckle observations taken at the Carlos U. Cesco Observatory, El Leoncito, Argentina, using a multianode microchannel array detector during the period 1994 July to 1996 July.
- ID:
- ivo://CDS.VizieR/J/ApJS/131/561
- Title:
- Double stars with PISCO at Pic du midi
- Short Name:
- J/ApJS/131/561
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present astrometric measurements of binary stars based on speckle observations of 164 independent sequences of observations (~10^4^ frames each) made with the PISCO speckle camera at Pic du Midi. These measurements concern 147 objects, of which 134 were found to be double with a separation in the range 0.1"-1.0". These objects were mainly selected among grade 3 orbits to improve the accuracy of their orbits and to constrain their masses. We discovered the binarity of 59 Aql with an angular separation of 0.09"+/-0.01".
- ID:
- ivo://CDS.VizieR/III/278
- Title:
- Double stars with wide separations in the AGK3
- Short Name:
- III/278
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A large list of common proper motion stars selected from the third Astronomischen Gesellschaft Katalog (AGK3) was monitored with the CORAVEL (for COrrelation RAdial VELocities) spectrovelocimeter, in order to prepare a sample of physical binaries with very wide separations. In paper I,66 stars received special attention, since their radial velocities (RV) seemed to be variable. These stars were monitored over several years in order to derive the elements of their spectroscopic orbits. In addition, 10 of them received accurate RV measurements from the SOPHIE spectrograph of the T193 telescope at the Observatory of Haute-Provence. For deriving the orbital elements of double-lined spectroscopic binaries (SB2s), a new method was applied, which assumed that the RV of blended measurements are linear combinations of the RV of the components. 13 SB2 orbits were thus calculated. The orbital elements were eventually obtained for 52 spectroscopic binaries (SBs), two of them making a triple system. 40 SBs received their first orbit and the orbital elements were improved for 10 others. In addition, 11 SBs were discovered with very long periods for which the orbital parameters were not found. It appeared that HD 153252 has a close companion, which is a candidate brown dwarf with a minimum mass of 50 Jupiter masses. In paper II, 80 wide binaries (WBs) were detected, and 39 optical pairs were identified. Adding CPM stars with separations close enough to be almost certain they are physical, a "bias-controlled" sample of 116 wide binaries was obtained, and used to derive the distribution of separations from 100 to 30,000 au. The distribution obtained doesn't match the log-constant distribution, but is in agreement with the log-normal distribution. The spectroscopic binaries detected among the WB components were used to derive statistical informations about the multiple systems. The close binaries in WBs seem to be similar to those detected in other field stars. As for the WBs, they seem to obey the log-normal distribution of periods. The number of quadruple systems is in agreement with the "no correlation" hypothesis; this indicates that an environment conducive to the formation of WBs doesn't favor the formation of subsystems with periods shorter than 10 years.
- ID:
- ivo://CDS.VizieR/J/MNRAS/458/3808
- Title:
- DR9-12 SDSS WDMS binaries
- Short Name:
- J/MNRAS/458/3808
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an updated version of the spectroscopic catalogue of white dwarf-main-sequence (WDMS) binaries from the Sloan Digital Sky Survey (SDSS). We identify 938 WDMS binaries within the data releases (DR) 9-12 of SDSS plus 40 objects from DR 1-8 that we missed in our previous works, 646 of which are new. The total number of spectroscopic SDSS WDMS binaries increases to 3294. This is by far the largest and most homogeneous sample of compact binaries currently available. We use a decomposition/fitting routine to derive the stellar parameters of all systems identified here (white dwarf effective temperatures, surface gravities and masses, and secondary star spectral types). The analysis of the corresponding stellar parameter distributions shows that the SDSS WDMS binary population is seriously affected by selection effects. We also measure the Na I {lambda}{lambda} 8183.27, 8194.81 absorption doublet and H {alpha} emission radial velocities (RV) from all SDSS WDMS binary spectra identified in this work. 98 objects are found to display RV variations, 62 of which are new. The RV data are sufficient enough to estimate the orbital periods of three close binaries.
- ID:
- ivo://CDS.VizieR/J/A+A/658/A63
- Title:
- DR Tau VLT/SPHERE and LBTI/LMIRCam maps
- Short Name:
- J/A+A/658/A63
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Protoplanetary disks around young stars often contain substructures like rings, gaps, and spirals that could be caused by interactions between the disk and forming planets. We aim to study the young (1-3Myr) star DR Tau in the near-infrared and characterize its disk, which was previously resolved through sub-millimeter interferometry with ALMA, and to search for possible sub-stellar companions embedded into it. We observed DR Tau with VLT/SPHERE both in polarized light (H broad band) and total intensity (in Y, J, H, and K spectral bands). We also performed L' band observations with LBTI/LMIRCam on the Large Binocular Telescope (LBT). We applied differential imaging techniques to analyze the polarized data, using dual beam polarization imaging (DPI), and total intensity data, using both angular and spectral differential imaging (ADI, SDI). We found two previously undetected spirals extending north-east and south of the star, respectively. We further detected an arc-like structure north of the star. Finally a bright, compact and elongated structure was detected at separation of 303+/-10 mas and position angle 21.2+/-3.7 degrees, just at the root of the north-east spiral arm. Since this feature is visible both in polarized light and in total intensity and has a flat spectrum it is likely caused by stellar light scattered by dust. The two spiral arms are at different separation from the star, have very different pitch angles, and are separated by an apparent discontinuity, suggesting they might have a different origin. The very open southern spiral arm might be caused by infalling material from late encounters with cloudlets into the formation environment of the star itself. The compact feature could be caused by interaction with a planet in formation still embedded in its dust envelope and it could be responsible for launching the north-east spiral. We estimate a mass of the putative embedded object of the order of few M Jup .
- ID:
- ivo://CDS.VizieR/J/AJ/150/151
- Title:
- DSSI observations of binaries. VI. Measures in 2014
- Short Name:
- J/AJ/150/151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of 938 speckle measures of double stars and suspected double stars drawn mainly from the Hipparcos Catalog, as well as 208 observations where no companion was noted. One hundred fourteen pairs have been resolved for the first time. The data were obtained during four observing runs in 2014 using the Differential Speckle Survey Instrument at Lowell Observatory's Discovery Channel Telescope. The measurement precision obtained when comparing to ephemeris positions of binaries with very well-known orbits is generally less than 2mas in separation and 0.5{deg} in position angle. Differential photometry is found to have internal precision of approximately 0.1mag and to be in very good agreement with Hipparcos measures in cases where the comparison is most relevant. We also estimate the detection limit in the cases where no companion was found. Visual orbital elements are derived for six systems.
- ID:
- ivo://CDS.VizieR/J/AJ/157/56
- Title:
- DSSI observations of binary & trinary star systems
- Short Name:
- J/AJ/157/56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 248 speckle observations of 43 binary and 19 trinary star systems chosen to make progress in two main areas of investigation: the fundamental properties of metal-poor stars and star formation mechanisms. The observations were taken at the Gemini North and South telescopes during the period 2015 July to 2018 April, mainly with the Differential Speckle Survey Instrument but also with a few early results from the new 'Alopeke speckle camera at Gemini North. We find that the astrometry and photometry of these observations as a whole are consistent with previous work at Gemini. We present five new visual orbits for systems important in understanding metal-poor stars, three of which have orbital periods of less than 4 yr, and we indicate the degree to which these and future observations can impact our knowledge of stellar properties and star formation. In particular, we find a decrease in mass at fixed spectral type for metal-poor stars versus their solar-metallicity analogs that is consistent with predictions that are made from current stellar models.
- ID:
- ivo://CDS.VizieR/J/A+A/650/A66
- Title:
- DS Tuc A radial velocity curve
- Short Name:
- J/A+A/650/A66
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The observations of young close-in exoplanets are providing first indications of the characteristics of the population and, in turn, clues on the early stages of their evolution. Transiting planets at young ages are also key benchmarks for our understanding of planetary evolution through the verification of atmospheric escape models. We performed a radial velocity (RV) monitoring of the 40Myr old star DS Tuc A with HARPS at the ESO-3.6m to determine the planetary mass of its 8.14-days planet, first revealed by the NASA TESS satellite. We also observed two planetary transits with HARPS and ESPRESSO at ESO-VLT, to measure the Rossiter-McLaughlin (RM) effect and characterise the planetary atmosphere. We measured the high-energy emission of the host with XMM-Newton observations to investigate models for atmospheric evaporation. We employed Gaussian Processes (GP) regression to model the high level of the stellar activity, which is more than 40 times larger than the expected RV planetary signal. GPs were also used to correct the stellar contribution to the RV signal of the RM effect. We extracted the transmission spectrum of DS Tuc A b from the ESPRESSO data and searched for atmospheric elements/molecules either by single-line retrieval and by performing cross-correlation with a set of theoretical templates. Through a set of simulations, we evaluated different scenarios for the atmospheric photo-evaporation of the planet induced by the strong XUV stellar irradiation. While the stellar activity prevented us from obtaining a clear detection of the planetary signal from the RVs, we set a robust mass upper limit of 14.4Me for DS Tuc A b. We also confirm that the planetary system is almost (but not perfectly) aligned. The strong level of stellar activity hampers the detection of any atmospheric compounds, in line with other studies presented in the literature. The expected evolution of DS Tuc A b from our grid of models indicates that the planetary radius after the photo-evaporation phase will be 1.8-2.0Re, falling within the Fulton gap. The comparison of the available parameters of known young transiting planets with the distribution of their mature counterpart confirms that the former are characterised by a low density, with DS Tuc A b being one of the less dense. A clear determination of their distribution is still affected by the lack of a robust mass measurement, in particular for planets younger than ~100Myr.
- ID:
- ivo://CDS.VizieR/J/PAZh/26/301
- Title:
- Dynamical stability of triple stars
- Short Name:
- J/PAZh/26/301
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The dynamic stability of 38 observed hierarchical triple stars with known orbital elements of the internal and external binary subsystems and component masses is considered. Four different criteria of dynamical stability are used. The observed stability parameters and their critical values are calculated by taking into account errors in the orbital elements and component masses.
