C.D.S. - SIMBAD4 rel 1.7 - 2020.01.28CET15:04:56

2013AJ....145..170O - Astron. J., 145, 170 (2013/June-0)

Studies of NGC 6720 with calibrated HST/WFC3 emission-line filter images. III. Tangential motions using AstroDrizzle images.


Abstract (from CDS):

We have been able to compare with astrometric precision AstroDrizzle processed images of NGC 6720 (the Ring Nebula) made using two cameras on the Hubble Space Telescope. The time difference of the observations was 12.925 yr. This large time base allowed the determination of tangential velocities of features within this classic planetary nebula. Individual features were measured in [N II] images as were the dark knots seen in silhouette against background nebular [O III] emission. An image magnification and matching technique was also used to test the accuracy of the usual assumption of homologous expansion. We found that homologous expansion does apply, but the rate of expansion is greater along the major axis of the nebula, which is intrinsically larger than the minor axis. We find that the dark knots expand more slowly than the nebular gas, that the distance to the nebula is 720 pc ±30%, and that the dynamic age of the Ring Nebula is about 4000 yr. The dynamic age is in agreement with the position of the central star on theoretical curves for stars collapsing from the peak of the asymptotic giant branch to being white dwarfs.

Abstract Copyright:

Journal keyword(s): instrumentation: miscellaneous - planetary nebulae: individual (Ring Nebula, NGC 6720)

Simbad objects: 4

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Number of rows : 4

N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
1 NAME Orion Nebula Cluster OpC 05 35.0 -05 29           ~ 1924 1
2 NGC 6543 PN 17 58 33.4042519454 +66 37 58.748961810   11.09 11.28     [WC] 1109 1
3 M 57 PN 18 53 35.0969571234 +33 01 44.883146221   15.405 15.769 15.901 16.062 DA(O?) 785 2
4 NGC 7293 PN 22 29 38.5453078023 -20 50 13.746093105 11.894 13.158 13.524 13.689 13.898 DAO.5 888 0

    Equat.    Gal    SGal    Ecl

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