Abstract We summarize the analysis of a new PG 1159 star, i.e., a hydrogen deficient pre-white dwarf detected in the ROSAT XRT all sky survey /1/. The X-ray source RX J2117.1+3412 is relatively faint (≈0.33 cnt s−1) and was selected for optical identification on the basis of its extreme X-ray softness. With V = 13.2, the counterpart of the X-ray source is in the optical the second brightest member of the PG1159 class. CCD imagery reveals that the star is surrounded by an old highly excited planetary nebula of faint surface brightness. Optical line profiles of HeII, CIV, and OVI and the overall optical and ROSAT PSPC (0.1–2.4 keV) energy distributions are compared to predictions of NLTE model atmospheres. We find an excellent agreement between the atmospheric parameters derived from optical and soft X-ray data. The effective temperature of the star is extremely high (150,000 K). Abundances of He, C and O are found to be consistent with those derived in other PG1159 stars whereas the surface gravity is significantly smaller in RXJ2117.1+3412. New optical spectra presented here show the presence of ultra-high excitation lines of O VIII.


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    Titel :

    Non-LTE analysis of a new pulsating PG 1159-type central star detected in the ROSAT XRT all sky survey


    Beteiligte:
    Werner, K. (Autor:in) / Motch, C. (Autor:in) / Pakull, M.W. (Autor:in)

    Erschienen in:

    Advances in Space Research ; 13 , 12 ; 399-402


    Erscheinungsdatum :

    1993-01-01


    Format / Umfang :

    4 pages




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Elektronische Ressource


    Sprache :

    Englisch



    Non-LTE Analysis of a New Pulsating PG 1159-Type Central Star Detected in the ROSAT XRT All Sky Survey

    Werner, K. / Motch, C. / Pakull, M. W. et al. | British Library Conference Proceedings | 1993



    Nr. 1159

    DataCite | 1867

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    ROSAT observations in star forming regions

    Krautter, J. | British Library Online Contents | 1992