- ID:
- ivo://CDS.VizieR/J/A+A/631/A108
- Title:
- Disks around post-AGB binaries fit results
- Short Name:
- J/A+A/631/A108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Post-asymptotic giant branch (pAGB) binaries are surrounded by circumbinary disks of gas and dust that are similar to protoplanetary disks found around young stars. We aim to understand the structure of these disks and identify the physical phenomena at play in their very inner regions. We want to understand the disk-binary interaction and to further investigate the comparison with protoplanetary disks. We conducted an interferometric snapshot survey of 23 post-AGB binaries in the near-infrared (H-band) using VLTI/PIONIER. We fit the multi-wavelength visibilities and closure phases with purely geometrical models with an increasing complexity (including two point-sources, an azimuthally modulated ring, and an over-resolved flux) in order to retrieve the sizes, temperatures, and flux ratios of the different components. All sources are resolved and the different components contributing to the H-band flux are dissected. The environment of these targets is very complex: 13/23 targets need models with thirteen or more parameters to fit the data. We find that the inner disk rims follow and extend the size-luminosity relation established for disks around young stars with an offset toward larger sizes. The measured temperature of the near-infrared circumstellar emission of post-AGB binaries is lower (Tsub~1200K) than for young stars, which is probably due to a different dust mineralogy and/or gas density in the dust sublimation region. The dusty inner rims of the circumbinary disks around post-AGB binaries are ruled by dust sublimation physics. Additionally a significant amount of the circumstellar $H$-band flux is over-resolved (more than 10% of the non-stellar flux is over-resolved in 14 targets). This hints that a source of unknown origin, either a disk structure or outflow. The amount of over-resolved flux is larger than around young stars. Due to the complexity of these targets, interferometric imaging is a necessary tool to reveal the interacting inner regions in a model-independent way.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/457/133
- Title:
- Displaced red and blue components objects
- Short Name:
- J/MNRAS/457/133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted a feasibility study to determine the effectiveness of using USNO-B1.0 data to preferentially detect objects with displaced red and blue components. A procedure was developed to search catalogue entries for such objects, which include M dwarfs paired with white dwarfs or with earlier main-sequence stars, and galaxies with asymmetric colour distributions. Residual differences between red and blue and infrared and blue scanned emulsion images define vectors, which, when appropriately aligned and of sufficient length, signal potential candidates. Test sample sets were analysed to evaluate the effective discrimination of the technique. Over 91000 USNO-B1.0 catalogue entries at points throughout the celestial sphere were then filtered for acceptable combinations of entry observations and magnitudes and the resulting total of about 17000 entries was winnowed down to a little more than 200 objects of interest. These were screened by visual examination of photo images to a final total of 146 candidates. About one quarter of these candidates coincide with SDSS (Sloan Digital Sky Survey) data. Those constituents fall into two groups, single and paired objects. SDSS identified several galaxies in the first group. Regarding the second group, at least half of its members were tentatively identified as main-sequence pairs, the greater portion being of widely separated spectral types. Two white dwarf-main-sequence pairs were also identified. Most importantly, the vectors formed from USNO-B1.0 residuals were in alignment with corresponding SDSS pair position angles, thereby supporting this work's central thesis.
- ID:
- ivo://CDS.VizieR/J/AJ/155/165
- Title:
- Dissipation in exoplanet hosts from tidal spin-up
- Short Name:
- J/AJ/155/165
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stars with hot Jupiters (HJs) tend to rotate faster than other stars of the same age and mass. This trend has been attributed to tidal interactions between the star and planet. A constraint on the dissipation parameter Q_*_' follows from the assumption that tides have managed to spin up the star to the observed rate within the age of the system. This technique was applied previously to HATS-18 and WASP-19. Here, we analyze the sample of all 188 known HJs with an orbital period <3.5 days and a "cool" host star (T_eff_<6100 K). We find evidence that the tidal dissipation parameter (Q_*_') increases sharply with forcing frequency, from 10^5^ at 0.5 day^-1^ to 10^7^ at 2 day^-1^. This helps to resolve a number of apparent discrepancies between studies of tidal dissipation in binary stars, HJs, and warm Jupiters. It may also allow for a HJ to damp the obliquity of its host star prior to being destroyed by tidal decay.
- ID:
- ivo://CDS.VizieR/J/MNRAS/492/2709
- Title:
- Double-lined spectroscopic binaries catalog
- Short Name:
- J/MNRAS/492/2709
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The study of a selected set of 69 double-lined spectroscopic binaries (SB2) with well defined visual and spectroscopic orbits was carried out. The orbital parallax, the mass, the colour, and the luminosity of each component were derived from observational data for almost all of these systems. We have also obtained an independent estimation of the component masses by comparing the colour-luminosity diagram (CMD) to the stellar evolution tracks reported by Pietrinferni. Nearly all of the observational points on the CMD are located between two tracks of slightly different mass or which fall very close to the one corresponding to a unique mass value. The masses obtained from the stellar model are in good agreement with their empirical values determined by parallax techniques (orbital, dynamical, and Gaia). This means that our adopted model is rather reliable and can therefore be used to infer further information, such as the age of each component in the studied systems. Our results indicate a fair correspondence between the age of primaries and secondary stars within 3{sigma}. Nevertheless, we caution that these age indications suffer of uncertainties due to both inhomogeneities/low precision of the adopted photometric data and possible systematics. Finally, it is statistically shown that along with the orbital and trigonometric parallaxes, the dynamical parallax can serve as a reliable tool for distance estimates.
- ID:
- ivo://CDS.VizieR/J/AJ/157/78
- Title:
- Double & multiple star systems from GaiaDR2
- Short Name:
- J/AJ/157/78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Binary and multiple stars have long provided an effective empirical method of testing stellar formation and evolution theories. In particular, the existence of wide binary systems (separations >20000 au) is particularly challenging to binary formation models as their physical separations are beyond the typical size of a collapsing cloud core (~5000-10000 au). We mined the recently published Gaia-DR2 catalog (Cat. I/345) to identify bright comoving systems in the five-dimensional space (sky position, parallax, and proper motion). We identified 3741 comoving binary and multiple stellar candidate systems, out of which 575 have compatible radial velocities for all the members of the system. The candidate systems have separations between ~400 and 500000 au. We used the analysis tools of the Virtual Observatory to characterize the comoving system members and to assess their reliability. The comparison with previous comoving systems catalogs obtained from TGAS showed that these catalogs contain a large number of false systems. In addition, we were not able to confirm the ultra-wide binary population presented in these catalogs. The robustness of our methodology is demonstrated by the identification of well known comoving star clusters and by the low contamination rate for comoving binary systems with projected physical separations <50000 au. These last constitute a reliable sample for further studies. The catalog is available online at the Spanish Virtual Observatory portal (http://svo2.cab.inta-csic.es/vocats/v2/comovingGaiaDR2/).
- ID:
- ivo://CDS.VizieR/J/MNRAS/259/563
- Title:
- Double star CCD observations
- Short Name:
- J/MNRAS/259/563
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+AS/134/545
- Title:
- Double star measurements 1995-1997
- Short Name:
- J/A+AS/134/545
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present speckle observations of 48 double and multiple stars observed with the 2-meter ``Telescope Bernard Lyot'' (TBL) in December 1995, January 1997 and June 1997. Angular separations, absolute position angles and relative photometry result from these observations. New orbital elements have been recalculated for 8 double stars.
- ID:
- ivo://CDS.VizieR/J/A+A/396/933
- Title:
- Double star measurements at Nice Obs.
- Short Name:
- J/A+A/396/933
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present (table 1) the measurements of 167 visual double stars, made in 2000 and 2001 with the 50 cm refractor of the Nice Observatory and attached CCD camera, using an algorithm based on the adjustment of a tridimensional mathematical surface. Position angle, angular separation and magnitude difference are given. 33 new binaries (discovered by HIPPARCOS (HDS) or newly determined from Tycho-2 database (TDS)) discovered by Hipparcos were measured.
- ID:
- ivo://CDS.VizieR/J/A+A/464/641
- Title:
- Double stars CCD photometry and astrometry. III
- Short Name:
- J/A+A/464/641
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent CCD observations were performed in the period 1998-2004 for a large sample of visual double and multiple stars selected from the Hipparcos Catalogue (Cat. <I/239>) and/or from the Gliese Catalogue of Nearby Stars (Cat. <V/70>). Accurate astrometric and photometric data allowing us to characterise the individual components are provided. These data are compared to Hipparcos data or to data from an older epoch to assess the nature of the observed systems. We simultaneously apply a Moffat-Lorentz profile with a similar shape to all detected components and adjust the profile parameters from which we obtain the relative astrometric position (epoch, position angle, angular separation) as well as differential multi-colour photometry (filters (B)VRI).
- ID:
- ivo://CDS.VizieR/J/AJ/132/50
- Title:
- Double stars in astrometric catalogs
- Short Name:
- J/AJ/132/50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The US Naval Observatory has mined over 140 astrometric catalogs, including the Astrographic Catalogue and the Two Micron All Sky Survey, for measures of double stars. This resulted in 114,218 new measures of 47,007 different systems spanning 110 years; these are now included in the Washington Double Star catalog (WDS). This is the single largest data set ever added to the WDS. The measures are typically of wider pairs, most between 4" and 30" thus, their value in aiding orbit determination is limited. However, they have proven invaluable in the verification of systems and the determination of rectilinear motions of systems.
