- ID:
- ivo://CDS.VizieR/J/AJ/158/48
- Title:
- Speckle interferometry at SOAR in 2018
- Short Name:
- J/AJ/158/48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of speckle interferometric observations at the 4.1 m Southern Astrophysical Research Telescope (SOAR) in 2018 are given, totaling 3097 measurements of 2427 resolved pairs with separations from 11 mas to 5.9" (median 0.15", magnitude difference up to 7 mag) and nonresolutions of 624 targets. This work continues our long-term speckle program. Its main goal is to monitor orbital motion of close binaries, including members of high-order hierarchies and Hipparcos pairs in the solar neighborhood. Also, pre-main-sequence stars in the Orion OB1 association were surveyed, resolving 26 out of 118 targets. In addition, we report the discovery of 35 new companions among field visual multiples (some of which are likely optical) and first-time resolutions of another 31 pairs. By combining the measurements given here with the published ones, we computed 76 orbits for the first time and updated orbital elements of 34 visual binaries. Their periods range from 0.65 to 1100 yr, and their quality varies from first tentative solutions of grade 5 to accurate elements of grades 1 and 2. Finally, a list of 53 spurious pairs discovered by various techniques and unresolved at SOAR is given.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/155/235
- Title:
- Speckle interferometry at SOAR in 2016 and 2017
- Short Name:
- J/AJ/155/235
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of speckle interferometric observations at the 4.1 m Southern Astrophysical Research Telescope in 2016 and 2017 are given, totaling 2483 measurements of 1570 resolved pairs and 609 non-resolutions. We describe briefly recent changes in the instrument and observing method and quantify the accuracy of the pixel scale and position angle calibration. Comments are given on 44 pairs resolved here for the first time. The orbital motion of the newly resolved subsystem BU 83 Aa,Ab roughly agrees with its 36-year astrometric orbit proposed by J. Dommanget. Most Tycho binaries examined here turned out to be spurious.
- ID:
- ivo://CDS.VizieR/J/AJ/161/253
- Title:
- Speckle interferometry at the OAN-SPM Mexico
- Short Name:
- J/AJ/161/253
- Date:
- 09 Mar 2022
- Publisher:
- CDS
- Description:
- In this paper we present multiband speckle interferometric measurements of double stars performed at the 2.1m telescope of the Observatorio Astronomico Nacional, San Pedro Martir, Mexico. We focused our efforts on objects from the Washington Double Star Catalog that were observed during five runs allocated in 2018 and 2019. We report here 2101 astrometric and 2027 photometric measurements of 631 pairs, with angular separations ranging from 0.05" to 6.09", including 1622 measurements with separations smaller than 1", and a magnitude difference up to 5.99mag through the V filter, 5.46mag for the R filter, and 5.85mag for the I filter. We estimated a mean error in separation of 12mas, 1.1{deg} in position angle, and 0.14mag for the magnitude difference. We confirmed 58 double stars discovered by Hipparcos. For the first time we are presenting astrometric measurements for 7 systems listed at the Washington Double Star Catalog as being suspected binaries, which did not have a secondary confirmation, and 15 stars with only one published measurement. We identified a new close companion with a mean angular separation of 0.10", detected in a previously known pair. Finally, we present a correction to two previously published orbital solutions of two visual binaries.
- ID:
- ivo://CDS.VizieR/J/AJ/150/16
- Title:
- Speckle-interferometry in Melotte 111
- Short Name:
- J/AJ/150/16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a high-angular resolution survey for the search of binary and multiple stars in the Galactic open cluster Melotte 111. Combining our own speckle-interferometric observations with data taken from the literature, we found a ratio of the number of single to multiple stars to be 29:8:0:0:0:1 for the most probable members, indicating a multiplicity fraction for this cluster of 25.6%+/-2%. We also observed field stars in the vicinity of the cluster and estimated a ratio of multiplicities of 286:17:1:0:0:0:1 (between one and seven companions), equivalent to a multiplicity fraction of 5.9%+/-3%. We showed that the cumulative distribution of separations for our sample stars is in agreement with Opik's law.
- ID:
- ivo://CDS.VizieR/J/AJ/162/156
- Title:
- Speckle interfero. nearby multiple stars. II
- Short Name:
- J/AJ/162/156
- Date:
- 14 Mar 2022 06:50:24
- Publisher:
- CDS
- Description:
- Long-term monitoring at the 6m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences made it possible to improve the orbits of 15 objects (HIP689, HIP3951, HIP10438, HIP43948, HIP69962, HIP95995, HIP102029, HIP102357, HIP104383, HIP105947, HIP106255, HIP108917, HIP111546, HIP113726, HIP114922) and construct an orbital solution for HIP65327 for the first time. Observations have been carried out since 2007; that is, the accumulated data correspond to an interval of 13yr. As a result, most of the orbits were classified as "accurate" using the qualitative criteria by Worley & Heintz. A comparison of the mass sums and masses of the components calculated by two independent methods was made for objects with orbital solutions. The Gaia EDR3 parallax was used to obtain the fundamental parameters, as well as the Hipparcos and Gaia DR2 parallaxes.
- ID:
- ivo://CDS.VizieR/J/AJ/158/167
- Title:
- Speckle observations & orbits of multiple stars
- Short Name:
- J/AJ/158/167
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report results of speckle-interferometric monitoring of visual hierarchical systems using the newly commissioned instrument NN-EXPLORE Exoplanet and Stellar Speckle Imager at the 3.5 m WIYN telescope. During one year, 390 measurements of 129 resolved subsystems were made, while some targets were unresolved. Using our astrometry and archival data, we computed 36 orbits (27 for the first time). Spectro-interferometric orbits of seven pairs are determined by combining positional measurements with radial velocities measured, mostly, with the Center for Astrophysics digital speedometers. For the hierarchical systems HIP 65026 (periods 49 and 1.23 yr) and HIP 85209 (periods 34 and 1.23 yr) we determined both the inner and the outer orbits using astrometry and radial velocities and measured the mutual orbit inclinations of 11.3{deg}+/-1.0{deg} and 12.0{deg}+/-3.0{deg}, respectively. Four bright stars are resolved for the first time; two of those are triple systems. Several visual subsystems announced in the literature are shown to be spurious. We note that subsystems in compact hierarchies with outer separations less than 100 au tend to have less eccentric orbits compared to wider hierarchies.
- ID:
- ivo://CDS.VizieR/J/AJ/162/75
- Title:
- Speckle observations TESS exoplanet host stars. II.
- Short Name:
- J/AJ/162/75
- Date:
- 18 Mar 2022 09:30:45
- Publisher:
- CDS
- Description:
- We present high-angular-resolution imaging observations of 517 host stars of TESS exoplanet candidates using the 'Alopeke and Zorro speckle cameras at Gemini North and South. The sample consists mainly of bright F, G, K stars at distances of less than 500pc. Our speckle observations span angular resolutions of ~20mas out to 1.2", yielding spatial resolutions of <10-500au for most stars, and our contrast limits can detect companion stars 5-9mag fainter than the primary at optical wavelengths. We detect 102 close stellar companions and determine the separation, magnitude difference, mass ratio, and estimated orbital period for each system. Our observations of exoplanet host star binaries reveal that they have wider separations than field binaries, with a mean orbital semimajor axis near 100 au. Other imaging studies have suggested this dearth of very closely separated binaries in systems which host exoplanets, but incompleteness at small separations makes it difficult to disentangle unobserved companions from a true lack of companions. With our improved angular resolution and sensitivity, we confirm that this lack of close exoplanet host binaries is indeed real. We also search for a correlation between planetary orbital radii versus binary star separation; but, given the very short orbital periods of the TESS planets, we do not find any clear trend. We do note that in exoplanet systems containing binary host stars, there is an observational bias against detecting Earth-size planet transits due to transit depth dilution caused by the companion star.
- ID:
- ivo://CDS.VizieR/J/ApJ/884/L31
- Title:
- Spectra & HST obs. of gal. in 1ES1553+113 field
- Short Name:
- J/ApJ/884/L31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The relationship between galaxies and the state/chemical enrichment of the warm-hot intergalactic medium (WHIM) expected to dominate the baryon budget at low-z provides sensitive constraints on structure formation and galaxy evolution models. We present a deep redshift survey in the field of 1ES1553+113, a blazar with a unique combination of ultraviolet (UV)+X-ray spectra for surveys of the circumgalactic/intergalactic medium (CGM/IGM). Nicastro+ (2018Natur.558..406N) reported the detection of two OVII WHIM absorbers at z=0.4339 and 0.3551 in its spectrum, suggesting that the WHIM is metal rich and sufficient to close the missing baryons problem. Our survey indicates that the blazar is a member of a z=0.433 group and that the higher-z OVII candidate arises from its intragroup medium. The resulting bias precludes its use in baryon censuses. The z=0.3551 candidate occurs in an isolated environment 630kpc from the nearest galaxy (with stellar mass logM_*_/M_{sun}_~9.7), which we show is unexpected for the WHIM. Finally, we characterize the galactic environments of broad HI Ly{alpha} absorbers (Doppler widths of b=40-80km/s; T<~4x10^5^K) that provide metallicity-independent WHIM probes. On average, broad Ly{alpha} absorbers are ~2x closer to the nearest luminous (L>0.25L*) galaxy (700kpc) than narrow (b<30km/s; T<~4x10^5^K) ones (1300kpc) but ~2x further than OVI absorbers (350kpc). These observations suggest that gravitational collapse heats portions of the IGM to form the WHIM, but with feedback that does not enrich the IGM far beyond galaxy/group halos to levels currently observable in UV/X-ray metal lines.
- ID:
- ivo://CDS.VizieR/J/ApJ/771/114
- Title:
- Spectral analysis of 100 evolved PNe from SPM
- Short Name:
- J/ApJ/771/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have selected a group of 100 evolved planetary nebulae (PNe) and study their kinematics based upon spatially-resolved, long-slit, echelle spectroscopy. The data have been drawn from the San Pedro Martir Kinematic Catalogue of PNe (SPM Catalogue). The aim is to characterize in detail the global kinematics of PNe at advanced stages of evolution with the largest sample of homogenous data used to date for this purpose. The results reveal two groups that share kinematics, morphology, and photo-ionization characteristics of the nebular shell and central star luminosities at the different late stages under study. The typical flow velocities we measure are usually larger than seen in earlier evolutionary stages, with the largest velocities occurring in objects with very weak or absent [NII]{lambda}6584 line emission, by all indications the least evolved objects in our sample. The most evolved objects expand more slowly. This apparent deceleration during the final stage of PNe evolution is predicted by hydrodynamical models, but other explanations are also possible. These results provide a template for comparison with the predictions of theoretical models.
- ID:
- ivo://CDS.VizieR/J/ApJS/238/13
- Title:
- Spectral and timing results of 1ES 1959+650
- Short Name:
- J/ApJS/238/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the detailed timing and spectral results obtained during the Swift observations of the TeV-detected blazar 1ES 1959+650 in 2016 August-2017 November. The source continued its trend of gradually enhancing X-ray flaring activity in the 0.3-10keV energy range, starting in 2015 August, and a new highest historical brightness state was recorded twice. A long-term high state was superimposed by both weak and strong flares, and we detected 32 instances of intraday X-ray flux variability, including several occasions of extremely fast fluctuations with fractional amplitudes of 5.4%-7.5% within 1ks exposures. The 0.3-10keV spectra generally showed a best fit with the log-parabolic model, yielding a very wide range of the curvature parameter b and the photon index at 1keV. The position of the synchrotron SED peak Ep showed an extreme variability on various timescales between energies less than 0.1keV and 7.7+/-0.7keV, with 25% of the spectra peaking at hard X-rays. In 2017 May-November, the source mostly showed lower spectral curvature and an anticorrelation b-Ep, expected in the case of efficient stochastic acceleration of X-ray-emitting electrons. The 0.3-100GeV and optical-UV fluxes also attained their highest historical values in this period, although the latter showed an anticorrelation with the 0.3-10keV emission, which is explained by the stochastic acceleration of electrons with a narrow initial energy distribution, having an average energy significantly higher than the equilibrium energy.
