Open AccessFurther 2MASS mapping of hot dust in planetary nebulae
Author(s) -
Phillips J. P.,
RamosLarios G.
Publication year - 2006
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2006.10237.x
Subject(s) - physics , astrophysics , planetary nebula , sky , flux (metallurgy) , radiative transfer , astronomy , photon flux , reflection nebula , cosmic dust , photon , stars , optics , materials science , metallurgy
We have used 2 Micron All Sky Survey (2MASS) mapping results to investigate the distribution of hot dust continua in 12 planetary nebulae (PNe). The nature of this emission is unclear, but it is possible that where the continuum is extended, as is the case for M 1‐12 and NGC 40, then the grains concerned may be very small indeed. The absorption of individual photons by such grains may lead to sharp spikes in temperature, as has previously discussed for several other such outflows. Other sources (such as MaC 1‐4, He 2‐25, B1 2‐1 and K 3‐15) appear to be relatively compact, and the high temperatures observed are understandable in terms of more normal heating processes. It is possible that the grains in these cases are experiencing high radiant flux levels. Finally, it is noted that whilst the core of M 2‐2 appears to show hot grain emission, this is less the case for its more extended envelope. The situation may, in this case, be similar to that of NGC 2346, in which much of the emission is located within an unresolved nucleus. Similarly, it is noted that in addition to hot dust and gas thermal continua, the emission in the interior of NGC 40 may be enhanced through rotational–vibrational transitions of H 2 , and/or the 2p 3 P 0 –2s 3 S transition of He i .