J/ApJ/798/129 Internal proper motions in NGC2392 (Garcia-Diaz+, 2015)
Internal proper motions in the Eskimo nebula.
Garcia-Diaz MA.T., Gutierrez L., Steffen W., Lopez J.A., Beckman J.
<Astrophys. J., 798, 129 (2015)>
=2015ApJ...798..129G 2015ApJ...798..129G
ADC_Keywords: Planetary nebulae ; Proper motions ; Radial velocities
Keywords: ISM: kinematics and dynamics; planetary nebulae: individual: NGC 2392;
techniques: spectroscopic
Abstract:
We present measurements of internal proper motions at more than 500
positions of NGC 2392, the Eskimo Nebula, based on images acquired
with WFPC2 on board the Hubble Space Telescope at two epochs separated
by 7.695yr. Comparisons of the two observations clearly show the
expansion of the nebula. We measured the amplitude and direction of
the motion of local structures in the nebula by determining their
relative shift during that interval. In order to assess the potential
uncertainties in the determination of proper motions in this object,
in general, the measurements were performed using two different
methods, used previously in the literature. We compare the results
from the two methods, and to perform the scientific analysis of the
results we choose one, the cross-correlation method, because it is
more reliable. We go on to perform a "criss-cross" mapping analysis on
the proper motion vectors, which helps in the interpretation of the
velocity pattern. By combining our results of the proper motions with
radial velocity measurements obtained from high resolution
spectroscopic observations, and employing an existing 3D model, we
estimate the distance to the nebula to be 1.3kpc.
Description:
For the present work, we used the data from Paper I (Garcia-Diaz+,
2012ApJ...761..172G 2012ApJ...761..172G). They are high-resolution spectroscopic
observations of the Eskimo nebula obtained at the Observatorio
Astronomico Nacional San Pedro Martir (OAN-SPM), Baja California,
Mexico, during the nights of 2002 January 7-10. The data were obtained
with the Manchester Echelle Spectrometer attached to the 2.1m
telescope.
The data used in this study to measure the proper motions of the
Eskimo nebula consist of images which were retrieved from the HST
archive. The observations were made in two separate observing runs: on
2000 January 11 (Epoch-1), as part of program 8499, with Andrew S.
Fruchter as PI. The second-epoch data were obtained on 2007 September
21 (Epoch-2), from the science program 11122, with Bruce Balick, as PI.
Objects:
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RA (ICRS) DE Designation(s)
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07 29 10.77 +20 54 42.5 NGC 2392 = NAME ESKIMO NEBULA
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 56 536 Proper motions of NGC 2392
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
J/ApJ/714/1096 : Galactic planetary nebulae (Stanghellini+, 2010)
J/ApJ/689/194 : Distances of galactic planetary nebulae (Stanghellini+, 2008)
J/PAZh/33/657 : JHKLM photometry of eight planetary nebulae (Taranova+, 2007)
J/ApJS/124/195 : PN medium-resolution spectra (Hora+, 1999)
J/A+AS/132/13 : Planetary nebulae radial velocities (Durand+ 1998)
J/A+AS/94/399 : Absolute fluxes and distances of PN (Cahn+, 1992)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 6 F6.2 arcsec X [-22/29] Structure X axis position (4)
8- 13 F6.2 arcsec Y [-26/24] Structure Y axis position (4)
15- 21 F7.4 pix pmxp Structure proper motion along X in pixels (2)
23- 29 F7.4 pix pmyp Structure proper motion along Y in pixels (2)
31- 36 F6.2 km/s pmxv [-49.1/38.8] Structure proper motion along X
in km/s (3)
38- 43 F6.2 km/s pmyv [-35.4/48.7] Structure proper motion along Y
in km/s (3)
45- 49 F5.2 km/s pm [0.01/69.3] Proper motion vector
51- 56 F6.2 km/s RVel [-49.4/165] Radial velocity (1)
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Note (1): Calculated from high resolution spectra.
Note (2): the proper motions were computed from two [NII]6584Å images from
the HST archive separated by 7.695yr; the 2 epochs are 2000-01-11 (program
8499, ith Andrew S. Fruchter as PI); and 2007-09-21 (program 11122, with
Bruce Balick as PI)
Note (3): the proper motion in km/s is pm=4.74Dδr/δt (Eq.13);
the final derived distance of the Eskimo nebula (D=1.3kpc) is used.
Note (4): distances along X et Y from the central star (HIP 36369)
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History:
From electronic version of the journal
References:
Garcia-Diaz et al. Paper I. 2012ApJ...761..172G 2012ApJ...761..172G
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 08-Jun-2015