Watching PrePNe Evolve: 15 Years of HST Observations

Balick, B.; Gomez, T.; Frank, A.; Corradi, R. L. M.; Alcolea, J.; Vinkovich, D.
Bibliographical reference

Asymmetric Planetary Nebulae 5 conference, held in Bowness-on-Windermere, U.K., 20 - 25 June 2010, A. A. Zijlstra, F. Lykou, I. McDonald, and E. Lagadec, eds. (2011) Jodrell Bank Centre for Astrophysics

Advertised on:
2011
Number of authors
6
IAC number of authors
1
Citations
0
Refereed citations
0
Description
Multi-epoch HST images have been obtained for the pre planetary nebulae CRL618, CRL2688, and Hen3-1475. Each object shows clear and idiosyncratic expansion patterns. CRL618 consists of several well defined fingers with sharp tips. The lengths of the tips have increased by identical factors, ˜7%, over the course of seven years, suggesting a common expansion age of 100 years. The corresponding proper motions range up to ˜400 km s^{-1} assuming a distance of 900 pc. Trailing filaments of starlight-scattering dust expand at a far lower rate, ˜1-2%, in the same time. The bright lobes of CRL2688 expand uniformly at a rate of 2.6% in seven years, suggesting a brief ejection 250 y ago. Surprisingly, the set of concentric and nearly circular arcs that surround the lobes also expand uniformly, but at a third of the rate of the lobes. Thus it appears that the arcs were all formed in a brief event 750 years ago rather than episodically over several hundred years as is commonly believed. Finally, Hen3-1475 shows two expanding components. The first consists of a symmetric pair of two large arcs of dust extending over 5000 AU on opposite sides of the nucleus that expand radially and uniformly at 2% per decade (assuming a distance of 5 kpc). This implies speeds at the leading edge of the arcs as high as 1000 km s^{-1}. The second component is pairs of bright knots seen best in emission-line images. These move along and through the dust arcs at even higher proper motions leaving no disturbances in their wakes. The innermost pair of knots is being launched from the tips of a pair of narrow emission-line cones that straddle the nuclear region and whose base seems anchored to the nucleus.