Measurements of double stars 1993.67 - 1998.13
624 Micrometer Measurements of 224 pairs with a 32.5 cm Cassegrain, 719Measurements of 310 double stars with a 360 mm Newtonian are given.Tables 1 to 4 are available in electronic form only at the CDS130.79.128.5 or via http://cdsweb.u-strasbg.fr/Abstract.html
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The Polarizing Power of the Interstellar Medium in Taurus
We present a study of the polarizing power of dust in cold dense regions(dark clouds) compared with that of dust in the general interstellarmedium (ISM). Our study uses new polarimetric, optical, and spectralclassification data for 36 stars to carefully study the relation betweenpolarization percentage (p) and extinction ( AV ) in theTaurus dark cloud complex. We find two trends in our p-AVstudy: (1) stars that are background to the warm ISM show an increase inp with AV , and (2) the percentage of polarization of starsthat are background to cold dark clouds does not increase withextinction. We detect a break in the p-AV relation at anextinction of 1.3+/-0.2 mag, which we expect corresponds to a set ofconditions where the polarizing power of the dust associated with theTaurus dark clouds drops precipitously. This break point placesimportant restrictions on the use of polarimetry in studyinginterstellar magnetic fields.
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A new optical extinction law and distance estimate for the Taurus-Auriga molecular cloud
This paper presents optical spectrophotometry of field stars projectedon the Taurus-Auriga molecular cloud. We derive extinction laws forheavily reddened stars in this sample and show that the reddening lawthrough the dark cloud is nearly identical to the standard law forlambda-lambda(3600-6100) and AV approximately less than 3mag. Our spectroscopic parallaxes suggest a distance of 140 +/- 10 pcfor the northern portion of the cloud and show no compelling evidencefor a substantial variation in distance across the leading edge of thecloud.
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A preliminary compilation of DS-programme star positions
A catalog is presented of the double-star-program (DS-program) starpositions, listing right ascensions for 930 DSs and declinations for1225 DSs of the program. The positions were compiled from the observedvalues obtained between 1980 and 1987 with the meridian circles of sixUSSR observatories (the Moscow, Kazan', Kiev, Khar'kov, Odessa, andTashkent Observatories) and the Belgrade Observatory. The measurementsand the treatment of the observational material were performed using therelative method, and the FK-4 system stars were used as reference stars.
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Local intersteller medium
Radio, IR, optical, UV, and X-ray observations of the local interstellarmedium (LISM) are reviewed, confirming the previous suggestion that thesun is located near an edge of a giant cavern with a radius of about 180pc whose center coincides with the Sco-Cen associated center. It issuggested that the bright spots of soft X-rays observed near thegalactic poles are produced by an interaction of stellar winds with theouter edge of the local cloud near the ends of Tinbergen's (1982) 'patchof polarization'. Results indicate that the main source of ionization ofextended H II regions of low density in the LISM is the Lyman continuumradiation from Sco-Cen stars.
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Photometric variations of Orion population stars. V - A search for periodicities
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1987AJ.....94..137H&db_key=AST
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On the distribution of interstellar matter around the sun
Available data on interstellar line or EUV continuum absorptionattributable to the local (r equal to or less than 100 pc) interstellarmedium are presented and analyzed as a whole for clues leading to adeeper understanding of the spatial distribution and physical propertiesof this material. By using these data in conjunction with upper limitsprovided by polarization and color excess surveys and relatingeverything to the neutral-hydrogen column density, it is shown that thedata are consistent with a simple model that assumes the relativelypervasive presence of a tenuous (nH = 0.07 per cu cm), possibly warm (T= 1,000-10,000 K) gas extending uniformly out to considerable distancesfrom the sun in most directions. The only region manifestly clear ofthis material lies in the 200 deg to 270 deg galactic longitude range inboth high and low latitudes. Strong density discontinuities are clearlyobservable at r approximately 100-150 pc in the general directions ofthe Sco-Cen and Per associations and a weaker discontinuity much closerto the sun running along a ridge oriented parallel to the lineconnecting their centers. Beyond these fronts, the space density ofinterstellar matter must fall to very low values that extend out toseveral hundred parsecs or so from the sun. These results are notincompatible with H I, 21-cm, and soft X-ray all-sky surveys. Theimplication of these findings for the theory of the interstellar mediumand EUV visibility is briefly discussed.
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Photometric variations of Orion population stars. II Ae-irregular variables and T Tauri stars
UBVRI and H-alpha photometry of five T Tauri stars and threeAe-irregular variables obtained during the 1982/83 observing season atVVO and KPNO is presented. RY Tau shows very little change in color withbrightness, except in (V-R) where it actually becomes bluer as it fades.The 'turnaround' in (U-B) suggested in last year's data on CO Ori hasbeen confirmed when faint, the star ceases becoming redder as it dimsand begins to get bluer. The turnaround is also now clearly seen in B -V. Similar turnarounds are found in two of the Ae stars, BF Ori and UXOri, the latter confirming Zajtseva's (1973) result. These 'blueing'trends make interpretations of the variability based on dust obscurationimplausible. The Ae stars monitored were nearly indistinguishable intheir photometric behavior from the G-type weak emission line T Tauristars SU Aur and CO Ori, suggesting a common mechanism for theirvariability. A general scheme for integrating the diverse properties ofthese variables is proposed, which involves photospheric andchromospheric responses to strong surface magnetic fields.
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Polarimetric investigation of background stars in the region of T and RY Tau
Electropolarimetric observations of 97 background stars in the TTauri/RY Tauri region, obtained with the 40-cm Cassegrain telescope ofthe Biurakan Astrophysical Observatory in December 1982, are reportedand interpreted in terms of local-magnetic-field effects oncometary-nebula bending. The data are presented in a table, and thedependence of polarization position angle on declination is establishedin a graph and attributed to a continuous variation in the direction ofthe magnetic field. From the magnitude of the effect, however, it isconcluded that the observed bending of the cometary nebulae in theregion results from the combined influence of the local magnetic momentand the magnetic moment of the star itself (as proposed by Vardanian,1983) rather than from the local moment alone.
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Errata in Magnitudes of Stars in AGK3
Not Available
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Optical monitoring of Orion population stars. I - Results for some T Tauri and Herbig Ae/Be stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1982AJ.....87.1710H&db_key=AST
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The polarization of T and RY Tau.
Not Available
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