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מאמרים קשורים
Looking Into the Hearts of Bok Globules: Millimeter and Submillimeter Continuum Images of Isolated Star-forming Cores
We present the results of a comprehensive infrared, submillimeter, andmillimeter continuum emission study of isolated low-mass star-formingcores in 32 Bok globules, with the aim to investigate the process ofstar formation in these regions. The submillimeter and millimeter dustcontinuum emission maps together with the spectral energy distributionsare used to model and derive the physical properties of the star-formingcores, such as luminosities, sizes, masses, densities, etc. Comparisonswith ground-based near-infrared and space-based mid- and far-infraredimages from Spitzer are used to reveal the stellar content of the Bokglobules, association of embedded young stellar objects (YSOs) with thesubmillimeter dust cores, and the evolutionary stages of the individualsources. Submillimeter dust continuum emission was detected in 26 out ofthe 32 globule cores observed. For 18 globules with detected(sub)millimeter cores, we derive evolutionary stages and physicalparameters of the embedded sources. We identify nine starless cores,most of which are presumably prestellar, nine Class 0 protostars, andtwelve Class I YSOs. Specific source properties like bolometrictemperature, core size, and central densities are discussed as afunction of evolutionary stage. We find that at least two thirds (16 outof 24) of the star-forming globules studied here show evidence offorming multiple stars on scales between 1000 and 50,000 AU. However, wealso find that most of these small prototstar and star groups arecomprised of sources with different evolutionary stages, suggesting apicture of slow and sequential star formation in isolated globules.
| Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
| The Vienna-KPNO search for Doppler-imaging candidate stars. I. A catalog of stellar-activity indicators for 1058 late-type Hipparcos stars
We present the results from a spectroscopic Ca ii H&K survey of 1058late-type stars selected from a color-limited subsample of the Hipparcoscatalog. Out of these 1058 stars, 371 stars were found to showsignificant H&K emission, most of them previously unknown; 23% withstrong emission, 36% with moderate emission, and 41% with weak emission.These spectra are used to determine absolute H&K emission-linefluxes, radial velocities, and equivalent widths of theluminosity-sensitive Sr ii line at 4077 Ä. Red-wavelengthspectroscopic and Strömgren y photometric follow-up observations ofthe 371 stars with H&K emission are used to additionally determinethe absolute Hα -core flux, the lithium abundance from the Li i6708 Å equivalent width, the rotational velocity vsin i, theradial velocity, and the light variations and its periodicity. Thelatter is interpreted as the stellar rotation period due to aninhomogeneous surface brightness distribution. 156 stars were found withphotometric periods between 0.29 and 64 days, 11 additional systemsshowed quasi-periodic variations possibly in excess of ~50 days. Further54 stars had variations but no unique period was found, and four starswere essentially constant. Altogether, 170 new variable stars werediscovered. Additionally, we found 17 new SB1 (plus 16 new candidates)and 19 new SB2 systems, as well as one definite and two possible new SB3systems. Finally, we present a list of 21 stars that we think are mostsuitable candidates for a detailed study with the Doppler-imagingtechnique. Tables A1--A3 are only available in electronic form at theCDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Mesures de vitesses radiales. VII. Accompagnement AU sol DU programme d'observation DU satellite Hipparcos. Radial velocities. VII. Ground based measurements for Hipparcos.
We publish 734 radial velocities of stars distributed in 28 fields of4x4deg. We continue the PPO series (Fehrenbach et al. 1987; Duflot etal. 1990 and 1992), using the Fehrenbach objective prism method.
| A spectrophotometric survey of stars along the Milky Way. IV
In the present paper a catalogue of spectrophotometric quantities,spectral types, monochromatic magnitudes and colour equivalents is givenfor all stars brighter than the magnitude m4400 = 10.5 in aregion of the Milky Way in Perseus. No absorption is found for starscloser than about r = 100 pc. The absorbing clouds are situated atdistances closer than 1 kpc and at about 2.5 kpc in the local arm andthe Perseus arm, respectively. The space between the two arms is freefrom absorption. It is also concluded that the Perseus arm continuesbeyond l = 140 deg, containing not only hydrogen gas but also dust to atleast l = 150 deg), while the content of OB stars decreases abruptly atl = 140 deg.
| Stellar Spectra in Milky way Regions.VI. a Region in Camelopardalis.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1956ApJS....2..298M&db_key=AST
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תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | ג'ירף |
| התרוממות ימנית: | 04h04m39.22s |
| סירוב: | +56°44'31.7" |
| גודל גלוי: | 8.029 |
| מרחק: | 200.401 פארסק |
| תנועה נכונה: | 22.7 |
| תנועה נכונה: | -30 |
| B-T magnitude: | 9.417 |
| V-T magnitude: | 8.144 |
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