- ID:
- ivo://CDS.VizieR/J/A+A/574/A6
- Title:
- Study of 95 binaries closer than 18pc from the Sun
- Short Name:
- J/A+A/574/A6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We test whether or not the orbital poles of the systems in the solar neighbourhood are isotropically distributed on the celestial sphere. The problem is plagued by the ambiguity on the position of the ascending node. Of the 95 systems closer than 18pc from the Sun with an orbit in the 6th Catalogue of Orbits of Visual Binaries, the pole ambiguity could be resolved for 51 systems using radial velocity collected in the literature and CORAVEL database or acquired with the HERMES/Mercator spectrograph. For several systems, we can correct the erroneous nodes in the 6th Catalogue of Orbits and obtain new combined spectroscopic/astrometric orbits for seven systems [WDS 01083+5455Aa,Ab; 01418+4237AB; 02278+0426AB (SB2); 09006+4147AB (SB2); 16413+3136AB; 17121+4540AB; 18070+3034AB]. We used of spherical statistics to test for possible anisotropy. After ordering the binary systems by increasing distance from the Sun, we computed the false-alarm probability for subsamples of increasing sizes, from N=1 up to the full sample of 51 systems. Rayleigh-Watson and Beran tests deliver a false-alarm probability of 0.5% for the 20 systems closer than 8.1pc. To evaluate the robustness of this conclusion, we used a jackknife approach, for which we repeated this procedure after removing one system at a time from the full sample. The false-alarm probability was then found to vary between 1.5% and 0.1%, depending on which system is removed. The reality of the deviation from isotropy can thus not be assessed with certainty at this stage, because only so few systems are available, despite our efforts to increase the sample. However, when considering the full sample of 51 systems, the concentration of poles toward the Galactic position l=46.0{deg}, b=37{deg}, as observed in the 8.1pc sphere, totally vanishes (the Rayleigh-Watson false-alarm probability then rises to 18%).
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/818/73
- Title:
- Study of protostars in the Perseus molecular cloud
- Short Name:
- J/ApJ/818/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multiplicity study of all known protostars (94) in the Perseus molecular cloud from a Karl G. Jansky Very Large Array survey at Ka-band (8 mm and 1 cm) and C-band (4 and 6.6 cm). The observed sample has a bolometric luminosity range between 0.1 L_{sun}_ and ~33 L_{sun}_, with a median of 0.7 L_{sun}_. This multiplicity study is based on the Ka-band data, having a best resolution of ~0.065" (15 au) and separations out to ~43" (10000 au) can be probed. The overall multiplicity fraction (MF) is found to be 0.40+/-0.06 and the companion star fraction (CSF) is 0.71+/-0.06. The MF and CSF of the Class 0 protostars are 0.57+/-0.09 and 1.2+/-0.2, and the MF and CSF of Class I protostars are both 0.23+/-0.08. The distribution of companion separations appears bi-modal, with a peak at ~75 au and another peak at ~3000 au. Turbulent fragmentation is likely the dominant mechanism on >1000 au scales and disk fragmentation is likely to be the dominant mechanism on <200 au scales. Toward three Class 0 sources we find companions separated by <30 au. These systems have the smallest separations of currently known Class 0 protostellar binary systems. Moreover, these close systems are embedded within larger (50-400 au) structures and may be candidates for ongoing disk fragmentation.
- ID:
- ivo://CDS.VizieR/J/PASJ/68/92
- Title:
- Subaru NIR obs. of Pleiades stars in SEEDS survey
- Short Name:
- J/PASJ/68/92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We find a new substellar companion to the Pleiades member star, Pleiades HII 3441, using the Subaru telescope with adaptive optics. The discovery is made as part of the high-contrast imaging survey to search for planetary-mass and substellar companions in the Pleiades and young moving groups. The companion has a projected separation of 0.49+/-0.02 (66+/-2au) and a mass of 68+/-5MJ based on three observations in the J-, H-, and Ks-bands. The spectral type is estimated to be M7 (~2700K), and thus no methane absorption is detected in the H band. Our Pleiades observations result in the detection of two substellar companions including one previously reported among 20 observed Pleiades stars, and indicate that the fraction of substellar companions in the Pleiades is about 10.0^+26.1^_-8.8_%. This is consistent with multiplicity studies of both the Pleiades stars and other open clusters.
- ID:
- ivo://CDS.VizieR/J/ApJ/771/129
- Title:
- Submillimetric Class II sources of Taurus
- Short Name:
- J/ApJ/771/129
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a substantial extension of the millimeter (mm) wave continuum photometry catalog for circumstellar dust disks in the Taurus star-forming region, based on a new "snapshot" {lambda}=1.3mm survey with the Submillimeter Array. Combining these new data with measurements in the literature, we construct a mm-wave luminosity distribution, f(L_mm_), for Class II disks that is statistically complete for stellar hosts with spectral types earlier than M8.5 and has a 3{sigma} depth of roughly 3mJy. The resulting census eliminates a longstanding selection bias against disks with late-type hosts, and thereby demonstrates that there is a strong correlation between L_mm_ and the host spectral type. By translating the locations of individual stars in the Hertzsprung-Russell diagram into masses and ages, and adopting a simple conversion between L_mm_ and the disk mass, M_d_, we confirm that this correlation corresponds to a statistically robust relationship between the masses of dust disks and the stars that host them. A Bayesian regression technique is used to characterize these relationships in the presence of measurement errors, data censoring, and significant intrinsic scatter: the best-fit results indicate a typical 1.3mm flux density of ~25mJy for 1M_{sun}_ hosts and a power-law scaling L_mm_{propto}M_{star}_^1.5-2.0^. We suggest that a reasonable treatment of dust temperature in the conversion from L_mm_ to M_d_ favors an inherently linear M_d_{prop.to}M_*_ scaling, with a typical disk-to-star mass ratio of ~0.2%-0.6%. The measured rms dispersion around this regression curve is +/-0.7dex, suggesting that the combined effects of diverse evolutionary states, dust opacities, and temperatures in these disks imprint a full width at half-maximum range of a factor of ~40 on the inferred M_d_ (or L_mm_) at any given host mass.
- ID:
- ivo://CDS.VizieR/J/ApJ/799/155
- Title:
- Sub-stellar companions in Taurus
- Short Name:
- J/ApJ/799/155
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a large, high-spatial-resolution near-infrared imaging search for stellar and sub-stellar companions in the Taurus-Auriga star-forming region. The sample covers 64 stars with masses between those of the most massive Taurus members at ~3M_{sun}_ and low-mass stars at ~0.2M_{sun}_. We detected 74 companion candidates, 34 of these reported for the first time. Twenty-five companions are likely physically bound, partly confirmed by follow-up observations. Four candidate companions are likely unrelated field stars. Assuming physical association with their host star, estimated companion masses are as low as ~2M_Jup_. The inferred multiplicity frequency within our sensitivity limits between ~10-1500AU is 26.3_-4.9_^+6.6^%. Applying a completeness correction, 62%+/-14% of all Taurus stars between 0.7 and 1.4M_{sun}_ appear to be multiple. Higher order multiples were found in 1.8_-1.5_^+4.2^% of the cases, in agreement with previous observations of the field. We estimate a sub-stellar companion frequency of ~3.5%-8.8% within our sensitivity limits from the discovery of two likely bound and three other tentative very low-mass companions. This frequency appears to be in agreement with what is expected from the tail of the stellar companion mass ratio distribution, suggesting that stellar and brown dwarf companions share the same dominant formation mechanism. Further, we find evidence for possible evolution of binary parameters between two identified sub-populations in Taurus with ages of ~2Myr and ~20Myr, respectively.
- ID:
- ivo://CDS.VizieR/J/other/FrASS/8.624907
- Title:
- (Sub)Stellar companions of exoplanet hosts
- Short Name:
- J/other/FrASS/8.
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present the latest results of an ongoing multiplicity survey of exoplanet hosts, which was initiated at the Astrophysical Institute and University Observatory Jena, using data from the second data release of the ESA-Gaia mission. In this study the multiplicity of 289 targets was investigated, all located within a distance of about 500pc from the Sun. In total, 41 binary, and five hierarchical triple star systems with exoplanets were detected in the course of this project, yielding a multiplicity rate of the exoplanet hosts of about 16%. A total of 61 companions (47 stars, a white dwarf, and 13 brown dwarfs) were detected around the targets, whose equidistance and common proper motion with the exoplanet hosts were proven with their precise Gaia DR2 astrometry, which also agrees with the gravitational stability of most of these systems. The detected companions exhibit masses from about 0.016 up to 1.66M_{sun}_ and projected separations in the range between about 52 and 9555au.
- ID:
- ivo://CDS.VizieR/J/MNRAS/403/1089
- Title:
- SUNS and DEBRIS surveys target selection
- Short Name:
- J/MNRAS/403/1089
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Debris discs - analogous to the asteroid and Kuiper-Edgeworth belts in the Solar system - have so far mostly been identified and studied in thermal emission shortward of 100um. The Herschel space observatory and the Submillimetre Common-User Bolometer Array-2 (SCUBA-2) camera on the James Clerk Maxwell Telescope will allow efficient photometric surveying at 70 to 850um, which allows for the detection of cooler discs not yet discovered, and the measurement of disc masses and temperatures when combined with shorter wavelength photometry. The SCUBA-2 Unbiased Nearby Stars survey (SUNS) and the Disc Emission via a Bias-free Reconnaissance in the Infrared/Submillimetre (DEBRIS) Herschel Open Time Key Project are complementary legacy surveys observing samples of ~500 nearby stellar systems. To maximize the legacy value of these surveys, great care has gone into the target selection process. This paper describes the target selection process and presents the target lists of these two surveys.
- ID:
- ivo://CDS.VizieR/J/MNRAS/488/4905
- Title:
- SuperWASP transit false positive catalog
- Short Name:
- J/MNRAS/488/4905
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- SuperWASP, the Northern hemisphere WASP observatory, has been observing the skies from La Palma since 2004. In that time, more than 50 planets have been discovered with data contributions from SuperWASP. In the process of validating planets, many false-positive candidates have also been identified. The TESS telescope is set to begin observations of the northern sky in 2019. Similar to the WASP survey, the TESS pixel size is relatively large (13 arcsec for WASP and 21 arcsec for TESS), making it susceptible to many blended signals and false detections caused principally by grazing and blended stellar eclipsing binary systems. In order to reduce duplication of effort on targets, we present a catalogue of 1041 Northern hemisphere SuperWASP targets that have been rejected as planetary transits through follow-up observation.
- ID:
- ivo://CDS.VizieR/J/ApJS/247/66
- Title:
- SUPERWIDE: wide binaries in Gaia & SUPERBLINK
- Short Name:
- J/ApJS/247/66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 99203 wide binary systems, initially identified as common proper motion (CPM) pairs from a subset of ~5.2million stars with proper motions {mu}>40mas/yr, selected from Gaia data release 2 (DR2, I/345) and the SUPERBLINK high proper motion catalog (Lepine 2005, J/AJ/130/1247 and Lepine & Gaidos 2011, J/AJ/142/138). CPM pairs are found by searching for pairs of stars with angular separations <1{deg} and proper motion differences {Delta}{mu}<40mas/yr. A Bayesian analysis is then applied in two steps. In a first pass, we use proper motion differences and angular separations to distinguish between real binaries and chance alignments. In a second pass, we use parallax data from Gaia DR2 to refine our Bayesian probability estimates. We present a table of 119390 pairs which went through the full analysis, 99203 of which have probabilities >95% of being real wide binaries. Of those 99203 high-probability pairs, we estimate that only about 364 pairs are most likely to be false positives. In addition, we identify 57506 pairs that have probabilities greater than 10% from the first pass but have high parallax errors and therefore were not vetted in the second pass. We examine the projected physical separation distribution of our highest probability pairs and note that the distribution is a simple exponential tail and shows no evidence of being bimodal. Among pairs with lower probability, wide binaries are detected at larger separations (>10^4^-10^5^au), consistent with the very wide population suggested in previous studies; however, our analysis suggests that these do not represent a distinct population, but instead represent either the exponential tail of the "normal" wide binary distribution or are simply chance alignments of unrelated field stars. We examine the Hertzsprung-Russell diagram of this set of high-probability wide binaries and find evidence for 980 overluminous components among 2227 K+K wide binaries; assuming these represent unresolved subsystems, we determine that the higher-order multiplicity fraction for K+K wide systems is at least 39.6%.
- ID:
- ivo://CDS.VizieR/J/ApJ/783/123
- Title:
- Surface gravity for 220 Kepler stars
- Short Name:
- J/ApJ/783/123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a novel method for estimating lower-limit surface gravities (logg) of Kepler targets whose data do not allow the detection of solar-like oscillations. The method is tested using an ensemble of solar-type stars observed in the context of the Kepler Asteroseismic Science Consortium. We then proceed to estimate lower-limit log g for a cohort of Kepler solar-type planet-candidate host stars with no detected oscillations. Limits on fundamental stellar properties, as provided by this work, are likely to be useful in the characterization of the corresponding candidate planetary systems. Furthermore, an important byproduct of the current work is the confirmation that amplitudes of solar-like oscillations are suppressed in stars with increased levels of surface magnetic activity.
