Spectroscopy of planetary nebulae in M 33
Spectroscopy of planetary nebulae in M 33
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DOI：
10.1051/0004-6361:20030031
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发表时间：
2003-01
影响因子：
6.5
通讯作者：
L. Magrini;M. Perinotto;R. Corradi;A. E. G. D. D. A. E. S. Spazio-A.-E.-G.-D.-D.-A.-E.-S.-Spazio-102692068;Firenze Isaac Newton Group of Telescopes;L. Palma;S. I. A. D. Canarias;Tenerife;Spain.
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文献类型：
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作者：
L. Magrini;M. Perinotto;R. Corradi;A. E. G. D. D. A. E. S. Spazio-A.-E.-G.-D.-D.-A.-E.-S.-Spazio-102692068;Firenze Isaac Newton Group of Telescopes;L. Palma;S. I. A. D. Canarias;Tenerife;Spain.
用4.2米WHT望远镜(西班牙拉帕尔马)的AF2/WYFFOS光纤光谱仪，对M33的48个发射线天体进行了光谱观测。给出了42个天体的谱线强度和对数消光系数cβ。它们在沙巴丁和D‘Odorico诊断图上的位置(H�/(S II)与H�/(N II))表明，70%的候选星云是行星状星云(PNE)。在可测到4363U(O III)发射线的6个PNE中，有3个得到了化学丰度和星云物理参数。这些是圆盘PNE，位于4.1kpC的银心距离内，到目前为止，它们是直接测定化学丰度的最远的PNE。氦、氧和Ar的丰度与银河系中相应的PNE丰度没有发现差异。由于我们没有探测到任何(S三世)谱线，因此只获得了硫丰度的下限。N/H似乎低于银河系数值；讨论了这种低丰度的一些可能的解释。
Spectroscopic observations of 48 emission-line objects of M 33 have been obtained with the multi-object, wide field, fibre spectrograph AF2/WYFFOS at the 4.2m WHT telescope (La Palma, Spain). Line intensities and logarithmic extinction, cβ, are presented for 42 objects. Their location in the Sabbadin & D'Odorico diagnostic diagram (H�/(S ii) vs H�/(N ii)) suggests that >70% of the candidates are Planetary Nebulae (PNe). Chemical abundances and nebular physical parameters have been derived for the three of the six PNe where the 4363u (O iii) emission line was measurable. These are disc PNe, located within a galactocentric distance of 4.1 kpc, and, to date, they are the farthest PNe with a direct chemical abundance determination. No discrepancy in the Helium, Oxygen and Argon abundances has been found in comparison with corresponding abundances of PNe in our Galaxy. Only a lower limit to the sulphur abundance has been obtained since we could not detect any (S iii) line. N/H appears to be lower than the Galactic value; some possible explanations for this under-abundance are discussed.