- ID:
- ivo://CDS.VizieR/J/A+A/623/A72
- Title:
- Binarity of Hipparcos stars from Gaia pm anomaly
- Short Name:
- J/A+A/623/A72
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The census of stellar and substellar companions of nearby stars is largely incomplete, in particular towards the low mass brown dwarf and long-period exoplanets. It is however of fundamental importance to understand the stellar and planetary formation and evolution mechanisms. Nearby stars are particularly favorable targets for high precision astrometry. We aim at characterizing the presence of physical companions of stellar and substellar mass in orbit around nearby stars. Orbiting secondary bodies influence the proper motion of their parent star through their gravitational reflex motion. Using the Hipparcos and Gaia DR2 catalogs, we determine the long-term proper motion of the stars common to these two catalogs. We then search for a proper motion anomaly (PMa) between the long-term proper motion vector and the Gaia DR2 (or Hipparcos) measurements, indicative of the presence of a perturbing secondary object. We focus our analysis on the 6741 nearby stars located within 50pc, and we also present a catalog of the PMa for >99 percent of the stars of the full Hipparcos catalog. A fraction of 30 percent of the studied stars presents a PMa at a level of more than 3 sigma. The PMa allows us to detect orbiting companions, or set stringent limits to their presence. We present a few illustrations of the PMa analysis to interesting targets. We set upper limits of 0.1-0.3MJ to potential planets orbiting Proxima between 1 and 10au (P_orb_=3 to 100 years). We confirm that Proxima is gravitationally bound to alpha Cen. We recover the masses of the known companions of epsilon Eri, epsilon Ind, Ross 614 and beta Pic. We also detect the signature of a possible planet of a few jovian masses orbiting tau Ceti. Based on only 22 months of Gaia data, the DR2 has limitations, but its combination with the Hipparcos catalog and the very high accuracy of the derived PMa already enables to set valuable constraints on the binarity of nearby objects. The detection of tangential velocity anomalies at a median accuracy of sigma({Delta}v_T_)=1.0m/s per parsec of distance is already possible with the Gaia DR2. This type of analysis opens the possibility to identify long period orbital companions otherwise inaccessible. The complementarity of Gaia (for long orbital periods), radial velocity and transit techniques (for short periods) already appears as remarkably powerful.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/799/72
- Title:
- Binary AGNs from the VLA Stripe 82 survey
- Short Name:
- J/ApJ/799/72
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galaxy mergers play an important role in the growth of galaxies and their supermassive black holes. Simulations suggest that tidal interactions could enhance black hole accretion, which can be tested by the fraction of binary active galactic nuclei (AGNs) among galaxy mergers. However, determining the fraction requires a statistical sample of binaries. We have identified kiloparsec-scale binary AGNs directly from high-resolution radio imaging. Inside the 92deg^2^ covered by the high-resolution Very Large Array survey of the Sloan Digital Sky Survey (SDSS) Stripe 82 field, we identified 22 grade A and 30 grade B candidates of binary radio AGNs with angular separations less than 5" (10kpc at z=0.1). Eight of the candidates have optical spectra for both components from the SDSS spectroscopic surveys and our Keck program. Two grade B candidates are projected pairs, but the remaining six candidates are all compelling cases of binary AGNs based on either emission line ratios or the excess in radio power compared to the H{alpha}-traced star formation rate. Only two of the six binaries were previously discovered by an optical spectroscopic search. Based on these results, we estimate that ~60% of our binary candidates would be confirmed once we obtain complete spectroscopic information. We conclude that wide-area high-resolution radio surveys offer an efficient method to identify large samples of binary AGNs. These radio-selected binary AGNs complement binaries identified at other wavelengths and are useful for understanding the triggering mechanisms of black hole accretion.
- ID:
- ivo://CDS.VizieR/J/A+A/391/547
- Title:
- Binary and multiple clusters in the LMC
- Short Name:
- J/A+A/391/547
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on the Bica et al. (1999, Cat. <J/AJ/117/238>) catalogue we studied the star cluster system of the LMC area and provide a new catalogue of all binary and multiple cluster candidates found. As a selection criterion we used a maximum separation of 1.4' corresponding to 20pc (assuming a distance modulus of 18.5mag). We performed Monte Carlo simulations and produced artificial cluster distributions that we compared with the real one in order to check how many of the found cluster pairs and groups can be expected statistically due to chance superposition on the plane of the sky. In the cluster catalogue (file "clusters.dat"), identifiers and remarks, coordinates, object type, maximum and minimum diameter D_max_ and D_min_ and the position angle (P.A.) are taken from Bica et al. (1999, Cat. <J/AJ/117/238>). For the acronyms of the objects see the "Nomenclature Notes" section below, where their Table 1 is reproduced. The acronym used in the OGLE catalogue of star clusters in the LMC (e.g., LMC0012, (Pietrzynski & Udalski, 2000AcA....50..337P) is also given. The 9th column gives the separations (d) in pc found in the corresponding group, assuming a distance modulus of 18.5mag. The last column gives the ages available in the literature; the notes given in brackets indicate the reference. In some cases, only an age for the association of which the cluster appears to be part is found. If so, a corresponding remark is given in brackets.
- ID:
- ivo://CDS.VizieR/J/A+A/561/A8
- Title:
- Binary central stars of SMC PNe
- Short Name:
- J/A+A/561/A8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Optical Gravitational Lensing Experiment (OGLE), originally designed to search for microlensing events, provides a rich and uniform data set suitable for studying the variability of certain types of objects. We used the OGLE data to study the photometry of central stars of planetary nebulae (PNe) in the Small Magellanic Cloud (SMC). In particular, we searched for close binary central stars with the aim to constrain the binary fraction and period distribution in the SMC. We also searched for PNe mimics and removed them from the PNe sample. We identified 52 counterparts of PNe in the SMC in the I-band images from the OGLE-II and OGLE-III surveys. We analysed the time-series photometry of the PNe. Spectra of the photometric variables were obtained to constrain the nature of the objects or search for additional evidence for binarity. Eight variables were found. Of these, seven objects are PNe mimics, including one symbiotic star candidate. One close binary central star of PN with a period of 1.15 or 2.31 day was discovered. The obtained binary fraction for the SMC PNe and the observational biases are discussed in terms of the OGLE observations.
- ID:
- ivo://CDS.VizieR/J/A+A/496/813
- Title:
- Binary PNe towards the Galactic bulge
- Short Name:
- J/A+A/496/813
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Binarity has been hypothesised to play an important, if not ubiquitous, role in the formation of planetary nebulae (PNe). Yet there remains a severe paucity of known binary central stars required to test the binary hypothesis and to place strong constraints on the physics of the common-envelope (CE) phase of binary stellar evolution. Large photometric surveys offer an unrivalled opportunity to efficiently discover many binary central stars. We have combined photometry from the OGLE microlensing survey with the largest sample of PNe towards the Galactic bulge to systematically search for new binaries. A total of 21 periodic binaries were found thereby more than doubling the known sample. The orbital period distribution was found to be best described by CE population synthesis models when no correlation between primary and secondary masses is assumed for the initial mass ratio distribution. A comparison with post-CE white dwarf binaries indicates both distributions are representative of the true post-CE period distribution with most binaries exhibiting periods less than one day. An estimated close binary fraction of 12-21% is derived and is the first robust and independent validation of the prevailing 10-15% fraction estimated by Bond (2000, in Asymmetrical Planetary Nebulae II: From Origins to Microstructures, 199, 115). This suggests that binarity is not a precondition for the formation of PNe and that close binaries do not play a dominant role in the shaping of nebular morphologies. Systematic effects and biases of the survey are discussed with implications for future photometric surveys.
- ID:
- ivo://CDS.VizieR/J/A+A/564/A117
- Title:
- Binary quasars from LQAC-2
- Short Name:
- J/A+A/564/A117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Thanks to huge surveys, such as the Sloan Digital Sky Survey (SDSS), the last decade has shown a dramatic increase in the number of known quasars. In the second release of the general compiled catalogue Large Quasar Astrometric Catalogue (LQAC), 187504 objects are recorded. From this catalogue, we carry out statistical studies dealing with several topics: the astrometric accuracy of the quasars, their spatial location, the distribution of the distance to the closest neighbour, the identification of binary quasars, the completness of catalogues at a given magnitude and the estimation of the number of quasars expected to be detected by the astrometric space mission Gaia. We analyse the astrometric improvements brought by the LQAC-2 in terms of equatorial coordinates off-sets. We plot the bi-dimensional spatial distribution of the LQAC-2 quasars according to their equatorial, galactic, and ecliptic coordinates, thus exploring the anisotropy of the distribution. We compare the observed distribution of closest neighbours with the theoretical values based on a Poisson distribution. Moreover, we perform a comparison between two catalogues, the SDSS and the 2dF inside a huge common field. By extrapolating to the whole sky we deduce the number of quasars that will be detected by Gaia.
- ID:
- ivo://CDS.VizieR/J/AJ/131/1
- Title:
- Binary quasars in the SDSS
- Short Name:
- J/AJ/131/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of 221 new quasar pairs with proper transverse separations R_prop_<1h^1^Mpc over the redshift range 0.5<z<3.0, discovered from an extensive follow-up campaign to find companions around the Sloan Digital Sky Survey (Cat. <VII/243>) and 2dF QSO Redshift Survey (Cat. <VII/241>) quasars. This sample includes 26 new binary quasars with separations R_prop_<50h^-1^kpc ({thetas}<10"), more than doubling the number of such systems known. We define a statistical sample of binaries selected with homogeneous criteria and compute its selection function, taking into account sources of incompleteness. The first measurement of the quasar correlation function on scales 10h^-1^kpc<R_prop_<400h^-1^kpc is presented.
- ID:
- ivo://CDS.VizieR/J/ApJ/875/124
- Title:
- Binary red supergiants. II. B-type companions
- Short Name:
- J/ApJ/875/124
- Date:
- 20 Jan 2022 11:13:46
- Publisher:
- CDS
- Description:
- The percentage of massive main-sequence OB stars in binary systems is thought to be as high as 100%. However, very few Galactic binary red supergiants (RSGs) have been identified, despite the fact that these stars are the evolved descendants of OB stars. As shown in our recent paper, binary RSGs will likely have B-type companions, as dictated by stellar evolution considerations. Such a system will have a very unique photometric signature due to the shape of the spectral energy distribution. Using photometric cutoffs, it should therefore be possible to detect candidate RSG+B star binary systems. Here we present our spectroscopic follow-up observations of such candidates. Out of our initial list of 280 candidates in M31 and M33, we observed 149 and confirmed 63 as newly discovered RSG+B star binary systems. Additional spectra of four candidate systems in the Small Magellanic Cloud confirmed all of them as new RSG+B star binaries including the first known RSG+Be star system. By fitting BSTAR06 and MARCS model atmospheres to the newly obtained spectra, we place estimates on the temperatures and subtypes of both the B stars and RSGs. Overall, we have found 87 new RSG+B star binary systems in M31, M33 and the Small and Large Magellanic Clouds. Our future studies are aimed at determining the binary fraction of RSGs.
- ID:
- ivo://CDS.VizieR/J/AJ/127/1181
- Title:
- Binary speckle measurements at Calar Alto
- Short Name:
- J/AJ/127/1181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of our second observational run of binary star interferometric measurements with an ICCD speckle camera attached to the 1.52m telescope of the Observatorio Astronomico Nacional at Calar Alto (Almeria, Spain) in 2000 June-July are presented. The measured angular separations range from 0.096" to 6.558". With the use of the new speckle data, the orbits of the visual binaries WDS 14369+4813 and WDS 21597+4908 are improved.
- ID:
- ivo://CDS.VizieR/J/A+A/366/868
- Title:
- Binary speckle measurements at Calar Alto. I.
- Short Name:
- J/A+A/366/868
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results of our speckle interferometric measurements of binary stars made with the ICCD speckle camera using the 1.52-m telescope of the Observatorio Astronomico Nacional at Calar Alto (Spain) in September, 1999. The data contain 123 observations of 83 systems. The measured angular separations range from 0.153" to 6.727". We have used there new speckle measurements to improve the orbital elements for the binaries COU 247 and BU 524 AB.
