Bipolar nebulae: The missing population

Authors
Citation
Jp. Phillips, Bipolar nebulae: The missing population, PUB AST S P, 113(785), 2001, pp. 846-850
Citations number
22
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Space Sciences
Journal title
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC
ISSN journal
0004-6280 → ACNP
Volume
113
Issue
785
Year of publication
2001
Pages
846 - 850
Database
ISI
SICI code
0004-6280(200107)113:785<846:BNTMP>2.0.ZU;2-4
Abstract
We have undertaken an analysis of observed aspect ratios for the collimatio n disks in bipolar nebulae (BPNe). We find, as a result, that most such str uctures are likely to have a ratio of thickness to diameter b/a similar to 0.23. Similarly, the paucity of disks having aspect ratios greater than or equal to0.7 implies that many of the sources are either unobserved or, what is more probably the case, misidentified. It seems likely, as a result, th at the true population of BPNe is similar to1.7 times greater than previous ly supposed. Similarly, we determine that as many as of 43% of annular or r inglike planetaries may represent bipolar sources oriented along the line o f sight.