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Optical spectroscopic and 2MASS measurements of Stephenson Halpha stars
We present the results of spectroscopic observations for 52 objects fromthe list of Halpha emission stars of Stephenson(\cite{Ste86}). Out of six known T Tauri stars observed, five showedHalpha in emission and in one (StHa 40), Halpha changed from being in absorption to emission over a period of two years,accompanied by photometric and spectral type variability. We confirm theT Tauri nature of one Stephenson object (StHa 48) on the basis of thepresence of Halpha and Hbeta in emission, Li Ilambda6708 in absorption, infrared excess and X-ray emission. Among the52 objects observed, there were other emission line objects: 1 Ke star,1 BQ[ ] star, 2 galaxies and 2 Be stars. We present a higher-resolutionspectrum of StHa 62 showing permitted and forbidden lines in emissiontypical of BQ[ ] stars. Twenty five out of 30 newly observed objectsfailed to show Halpha in emission. We also present 2MASSobservations for 112 StHa objects. We suggest three Stephenson objects(StHa 52, 125 and 129) to be YSOs on the basis of 2MASS, IRAS and ROSATobservations. These and all other known YSOs amongst StHa stars arefound in regions of star-forming clouds in Taurus, Orion and Ophiuchus.YSOs at high galactic latitudes in other parts of the sky are thereforerare.Table 2 is only available in electronic form at the CDS via anonymousftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/402/963
| New H-alpha emission stars found above 10 deg galactic latitude
Approximately 1300 5.2 x 5.2 deg red-sensitive objective prism plateshave been searched for H-alpha emission stars in order to complete thesearch of the entire sky. The survey here reported represents 59 percentof the whole sky, defined by the region north of declination -25 deg andmostly further than 10 deg from the Galactic plane; the omitted portionshad already been surveyed, in part at Warner and Swasey, in partelsewhere. Two hundred and six stars have been newly found, mostly ofunknown spectral type. The stars' latitude distribution suggests thatthey are mainly moderately high luminosity disk population stars. Thereare new finds especially in Orion and the Taurus dark clouds (limitingmag of about 13).
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| Takýmyýldýz: | Yilanci |
| Sað Açýklýk: | 16h51m49.07s |
| Yükselim: | +11°26'56.3" |
| Görünürdeki Parlaklýk: | 9.852 |
| özdevim Sað Açýklýk: | -10.1 |
| özdevim Yükselim: | 12.7 |
| B-T magnitude: | 10.206 |
| V-T magnitude: | 9.882 |
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