- ID:
- ivo://CDS.VizieR/J/A+A/315/384
- Title:
- Binarity among B-stars in NGC 6231
- Short Name:
- J/A+A/315/384
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured radial velocities for 53 B-type stars, between B1 and B9, in the young open cluster NGC 6231 through a cross-correlation technique with synthetic spectra. Two measurements for 36 stars of the sample were obtained with a time separation of about two years. We derived a minimum binary fraction of 52% in the considered population. The velocity determination precisions were simulated and we analysed their dependence upon the S/N ratios of the spectra and upon the stellar rotational velocities. We discuss the selection of the templates for the correlation.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/428/2118
- Title:
- Binarity in planetary nebula central stars
- Short Name:
- J/MNRAS/428/2118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We still do not know what causes aspherical planetary nebula (PN) morphologies. A plausible hypothesis is that they are due to the presence of a close stellar or substellar companion. So far, only ~40 binary central stars of PN have been detected, almost all of them with such short periods that their binarity is revealed by photometric variability. Here we have endeavoured to discover binary central stars at any separation, thus determining the unbiased binary fraction of central stars of PN. This number, when compared to the binary fraction of the presumed parent population, can give a first handle on the origin of PN. By detecting the central stars in the I band we have searched for cool companions.
- 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.
- 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/MNRAS/508/2226
- Title:
- Binary central star of V510 Pup
- Short Name:
- J/MNRAS/508/2226
- Date:
- 19 Jan 2022 13:43:04
- Publisher:
- CDS
- Description:
- Current models predict that binary interactions are a major ingredient in the formation of bipolar planetary nebulae (PNe) and pre-planetary nebulae (PPNe). Despite years of radial velocity (RV) monitoring, the paucity of known binaries amongst the latter systems means data are insufficient to examine this relationship in detail. In this work, we report on the discovery of a long-period (P=2654+/-124d) binary at the centre of the Galactic bipolar PPN IRAS 08005-2356 (V510 Pup), determined from long-term spectroscopic and near-infrared time-series data. The spectroscopic orbit is fitted with an eccentricity of 0.36+/-0.05, which is similar to that of other long-period post-AGB binaries. Time-resolved H{alpha} profiles reveal high-velocity outflows (jets) with deprojected velocities up to 231^+31^_-27_km/s seen at phases when the luminous primary is behind the jet. The outflow traced by H{alpha} is likely produced via accretion on to a main-sequence companion, for which we calculate a mass of 0.63+/-0.13M_{sun}_. This discovery is one of the first cases of a confirmed binary PPN and demonstrates the importance of high-resolution spectroscopic monitoring surveys using large telescopes in revealing binarity among these systems.
- 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/ApJ/716/615
- Title:
- Binary compact object coalescence rates
- Short Name:
- J/ApJ/716/615
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we estimate binary compact object merger detection rates for LIGO, including the potentially significant contribution from binaries that are produced in elliptical galaxies near the epoch of peak star formation. Specifically, we convolve hundreds of model realizations of elliptical- and spiral-galaxy population syntheses with a model for elliptical- and spiral-galaxy star formation history as a function of redshift. Our results favor local merger rate densities of 4x10^-3^Mpc^-3^/Myr for binary black holes (BHs), 3x10^-2^Mpc^-3^/Myr for binary neutron stars (NSs), and 10^-2^Mpc^-3^/Myr for BH-NS binaries. Assuming a detection signal-to-noise ratio threshold of 8 for a single detector (in practice as part of a network, to reduce its noise), corresponding to radii Dbns of the effective volume inside of which a single LIGO detector could observe the inspiral of two 1.4M_{sun}_ NSs of 14Mpc and 197Mpc, for initial and advanced LIGO, we find event rates of any merger type of 2.9x10^-2^-0.46 and 25-400yr^-1^ (at 90% confidence level), respectively.
1699. Binary evolution
- ID:
- ivo://CDS.VizieR/J/MNRAS/319/215
- Title:
- Binary evolution
- Short Name:
- J/MNRAS/319/215
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using Eggleton's stellar evolution code, we carry out 150 runs of Population I binary evolution calculations with the initial primary mass between 1 and 8 solar masses, the initial mass ratio q=M_1/M_2 between 1.1 and 4, and the onset of Roche lobe overflow (RLOF) at an early, middle or late Hertzsprung-gap stage. We assume that the RLOF is conservative in the calculations. We list characteristics for binaries with different initial parameters at the beginning of RLOF, minimum luminosity during RLOF, the end of the last episode of RLOF and the end of the evolutionary calculations. The characteristics includes the age of the primary, its mass, mass transfer rate, its effective temperature, its luminosity, its radius, its helium core mass, its carbon-oxygen core mass, the hydrogen abundance at its surface, the mass ratio of the binary, and the orbital period.
- 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.
