Variation of Central Star Masses in Planetary Nebulae with Height above the Galactic Plane
There are various reasons for suspecting that the progenitor masses of planetarynebulae (PNe) decline with height z above the Galactic plane. This, if true,would also imply a similar decrease in mean central star masses <MCS>. We reporthere a further way in which such gradients may be determin...
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2004 |
| País: | México |
| Institución: | Universidad de Guadalajara |
| Repositorio: | Redalyc-UDG |
| OAI Identifier: | oai:redalyc.org:57140103 |
| Acceso en línea: | https://www.redalyc.org/articulo.oa?id=57140103 |
| Access Level: | acceso abierto |
| Palabra clave: | Física, Astronomía y Matemáticas STARS: EVOLUTION ISM: JETS AND OUTFLOWS PLANETARY NEBULAE:GENERAL |
| Sumario: | There are various reasons for suspecting that the progenitor masses of planetarynebulae (PNe) decline with height z above the Galactic plane. This, if true,would also imply a similar decrease in mean central star masses <MCS>. We reporthere a further way in which such gradients may be determined. It will beshown that the distribution of planetary nebulae with respect to 5 GHz brightnesstemperature varies strongly with Galactic latitude. This variation is likely to arisefrom a change in the central star mass function N(MCS). High latitude sources appearto have a steeply varying function N(MCS), implying the presence of relativelyfew nebulae with high central star masses. By contrast, the low latitude sourceshave a much gentler fall-off in N(MCS), implying a larger proportion of high MCSnebulae. This is shown to imply significant gradients of mean mass <MCS> withlatitude b. We find that d<MCS>/d/bLOW/ 2.0x10_3 Mo deg_1 for nebulaehaving 1.0 <log(TB/K)< 3.6, where /b/LOW/ represents the lower limit latitude ofthe sources. This corresponds to a gradient d<MCS>/d/zLOW/ 5.6x10_2 kpc_1for nebulae with heights /z/>/zLOW/, and where one adopts the statistical distancesof Phillips (2002). |
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