Pn – Ism Interaction: the Observational Evidence
نویسندگان
چکیده
We present results of an ongoing survey of low surface brightness planetary nebulae (PNe). Using both narrow-band imaging and long slit spectroscopy we have studied 15 new examples for interaction with the interstellar medium (ISM) demonstrating that this process is common in evolved PNe. Characteristic properties of the nebulae in terms of morphology and plasma parameters have been established and different degrees of interaction can be identified. Although the study of the objects is at an early stage the observational findings are in agreement with theory. The data indicate that the objects have a very high degree of individuality due to the action of complex physics under varying conditions.
منابع مشابه
The interaction of planetary nebulae and their AGB progenitors with the interstellar medium
Interaction with the Interstellar Medium (ISM) cannot be ignored in understanding planetary nebula (PN) evolution and shaping. In an effort to understand the range of shapes observed in the outer envelopes of PNe, we have run a comprehensive set of three-dimensional hydrodynamic simulations, from the beginning of the asymptotic giant branch (AGB) superwind phase until the end of the post–AGB/PN...
متن کاملNLTE Spectral Analysis of Central Stars of PNe Interacting with the ISM
The analysis of Planetary Nebulae (PNe) provides a tool to investigate the properties of their exciting central stars (CSPN) at the moment of the PN ejection as well as on the properties of the ambient interstellar medium (ISM). The spectral analysis of the CSPN is a prerequisite to calculate the ionizing flux which is a crucial input for reliable PN modeling. In the framework of a systematic s...
متن کاملEffects of Stellar-Mass and the ISM on the Evolving Morphologies of Planetary Nebulae
A significant step forward in the understanding of Planetary Nebula (PN) formation can be achieved by exploring the connection of PN with stellar evolution. In particular, the initial mass of the star plays a crucial role, as it determines the evolutionary timescales, the density structure of the gas and the amount of energy injected into the nebula. Here we summarize our study of the effects o...
متن کاملProbing the Magnetized Interstellar Medium Surrounding the Planetary Nebula Sh2-216
We present 1420 MHz polarization images of a 2.5 × 2.5 region around the planetary nebula (PN) Sh 2-216. The images are taken from the Canadian Galactic Plane Survey (CGPS). An arc of low polarized intensity (size 0.2×0.7) appears prominently in the north-east portion of the visible disk of Sh 2-216, coincident with the optically identified interaction region between the PN and the interstellar...
متن کاملo - ph . G A ] 1 J un 2 01 6 Dicke ’ s Superradiance in Astrophysics . I – The 21 cm Line
We have applied the concept of superradiance introduced by Dicke in 1954 to astrophysics by extending the corresponding analysis to the magnetic dipole interaction characterizing the atomic hydrogen 21 cm line. Although it is unlikely that superradiance could take place in thermally relaxed regions and that the lack of observational evidence of masers for this transition reduces the probability...
متن کامل