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Adaptive-Optics-Assisted Near-Infrared Spectroscopy of SVS 13 and Its Jet
We present long-slit H- and K-band spectroscopy of the low-mass outflowsource SVS 13, obtained with the adaptive-optics-assistedimager-spectrometer NACO on the VLT. With a spatial resolution of<0.25" and a pixel scale of 0.027", we precisely establish therelative offsets of H2, [Fe II], CO, H I, and Na I componentsfrom the source continuum. The H2 and [Fe II] peaks areclearly associated with the jet, while the CO, H I, and Na I peaks arespatially unresolved and coincident with the source, as is expected foremission associated with accretion processes. The H2 profilealong the slit is resolved into multiple components, which increase insize, although they decrease in intensity, with distance from thesource. This trend might be consistent with thermal expansion of packetsof gas ejected during periods of increased accretion activity. Indeed,for the brightest component nearest the source, proper-motionmeasurements indicate a tangential velocity of 0.028" yr-1.It therefore seems unlikely that this emission peak is associated with astationary zone of warm gas at the base of the jet. However, the samecannot be said for the [Fe II] peak, for which we see no evidence formotion downwind, even though radial velocity measurements indicate thatthe emission is associated with higher jet velocities. We postulate thatthe [Fe II] could be associated with a collimation shock at the base ofthe jet.Based on Observations collected at the European Southern Observatory,Paranal, Chile (ESO programs 074.C-0408).
| Radial velocities. Measurements of 2800 B2-F5 stars for HIPPARCOS
Radial velocities have been determined for a sample of 2930 B2-F5 stars,95% observed by the Hipparcos satellite in the north hemisphere and 80%without reliable radial velocity up to now. Observations were obtainedat the Observatoire de Haute Provence with a dispersion of 80Ä,mm(-1) with the aim of studying stellar and galactic dynamics.Radial velocities have been measured by correlation with templates ofthe same spectral class. The mean obtained precision is 3.0 km s(-1)with three observations. A new MK spectral classification is estimatedfor all stars. Based on observations made at the Haute ProvenceObservatory, France and on data from The Hipparcos Catalogue, ESA.Tables 4, 5 and 6 are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr or viahttp://cdsweb.u-strasbg.fr/Abstract.htm
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| קבוצת-כוכבים: | עגלון |
| התרוממות ימנית: | 06h29m39.49s |
| סירוב: | +28°46'50.4" |
| גודל גלוי: | 7.534 |
| מרחק: | 10000000 פארסק |
| תנועה נכונה: | -0.1 |
| תנועה נכונה: | -5.6 |
| B-T magnitude: | 7.483 |
| V-T magnitude: | 7.53 |
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