BD–22°3467, a DAO-type star exciting the nebula Abell 35

A barium central star binary in the Type - I diamond ring planetary nebula Abell 70 ⋆

Abell 70 (PN G038.1−25.4, hereafter A 70) is a planetary nebula (PN) known for its diamond ring appearance due a superposition with a background galaxy. The previously unstudied central star is found to be a binary consisting of a G8IV-V secondary at optical wavelengths and a hot white dwarf (WD) at UV wavelengths. The secondary shows Ba II and Sr II features enhanced for its spectral type that...

The separation of the stars in the binary nucleus of the planetary nebula Abell 35

Using the Planetary Camera on board the Hubble Space Telescope we have measured the projected separation of the binary components in the nucleus of the planetary nebula Abell 35 to be larger than 0.08 but less than 0.14. The system was imaged in three filters centered at 2950Å, 3350Å and 5785Å. The white dwarf primary star responsible for ionizing the nebula is half as bright as its companion i...

The Exciting Star VES 735

Physical conditions in the planetary nebula Abell 30

We have analysed optical spectra of two of the hydrogen-deficient knots (J1 & J3) in the born-again planetary nebula Abell 30, together with UV spectra of knots J3 & J4. We determine electron temperatures in the knots based on several diagnostics. The [O III] nebular-toauroral transition ratio yields temperatures of the order of 17 000 K. The weak temperature dependence of the ratios of helium ...

the investigation of the relationship between type a and type b personalities and quality of translation

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