Title of article :
Helium abundances in inner Galaxy planetary nebulae
Author/Authors :
Oscar Cavichia، نويسنده , , Roberto D. D. Costa، نويسنده , , Walter J. Maciel، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2009
Abstract :
New helium abundances of planetary nebulae located towards the bulge of the Galaxy were derived, based on observations made at OPD (Brazil). We present accurate helium abundances for 56 PNe located towards the galactic bulge. The data show good agreement with other results in the literature, in the sense that the distribution of the abundances is similar to previous works. Furthermore, the radial helium gradient is extended towards the galactic center. The results show that no trend can be identified when comparing the internal gradient (R < 4 kpc) to the whole galactic disk.
Keywords :
ISM: planetary nebulae: general , galaxy: abundances , Evolution
Journal title :
Proceedings of the International Astronomical Union
Journal title :
Proceedings of the International Astronomical Union