The Origins of Planetary Nebulae in the Inner and Outer Disks of M 31

Balick, B.; Kwitter, Karen; Corradi, R.; Galera Rosillo, R.; Henry, Richard
Referencia bibliográfica

Planetary Nebulae: Multi-Wavelength Probes of Stellar and Galactic Evolution, Proceedings of the International Astronomical Union, IAU Symposium, Volume 323, pp. 264-268

Fecha de publicación:
10
2017
Número de autores
5
Número de autores del IAC
1
Número de citas
2
Número de citas referidas
2
Descripción
The planetary nebulae (PNe) of M 31 are receiving considerable attention as probes of its structure and chemical evolution in a galactic environment that is putatively similar to the Milky Way. We have obtained deep spectra for about 30 luminous PNe in M 31's inner disk and beyond (R gal < 105 kpc). The entire ensemble of PNe exhibit O/H ~ 2/3 solar with no discernible radial gradient, in stark contrast to the H ii regions of M 31. This suggests that the outer PNe in M 31 formed from a common O-rich ISM at least 5 GY ago. We infer that the outer PNe and the underlying stellar population have little common history in M 31, and that the formation of the O-rich PNe preceded any putative encounter with M 33 ~2-3 Gy ago.