J/A+A/687/A123 PN Me 2-1 images and spectra (Miranda+, 2024)
Morphokinematical study of the planetary nebula Me 2-1:
Unveiling its point-symmetric and unusual physical structure.
Miranda L.F., Vazquez R., Olguin L., Guillen P.F., Matias J.M.
<Astron. Astrophys. 687, A123 (2024)>
=2024A&A...687A.123M 2024A&A...687A.123M (SIMBAD/NED BibCode)
ADC_Keywords: Planetary nebulae ; Spectra, optical
Keywords: circumstellar matter - stars: winds and outflows -
ISM: jets and outflows - planetary nebulae: individual: Me 2-1
Abstract:
Me 2-1 is a high-excitation planetary nebula whose morphology and
physical structure have not yet been investigated. We present
narrow-band images in several emission lines, and high- and
intermediate-resolution long-slit spectra aimed at investigating its
morphology and 3D structure, and its physical parameters and chemical
abundances. By applying deconvolution techniques to the images, we
identified in Me 2-1 an elliptical ring, two elongated, curved
structures (caps) that contain three pairs of bright point-symmetric
knots (PS-knots), a shell interior the ring, and a faint halo or
attached shell. The caps are observed in all images while the PS-knots
only in the low-excitation emission line ones. These structures are
also identified in the high-resolution long-slit spectra, hence
allowing us to study their morphokinematics. The 3D reconstruction
shows that Me 2-1 consists of a ring seen almost pole-on, and a
virtually spherical shell, to which the caps and PS-knots are
attached. Caps and PS-knots most probably trace the sites where
high-velocity collimated bipolar outflows, ejected along a wobbling
axis, collide with the spherical shell, are slowed down, and remain
attached to it. Although the main excitation mechanism in Me 2-1 is
found to be photoionization, a contribution of shocks in the PS-knots
is suggested by their emission line ratios. The combination of
collimated outflows and a ring with a spherical shell is unusual among
planetary nebulae. We speculate that two planets, each with lesser
than one Jupiter mass, could be involved in the formation of Me 2-1 if
both enter a common envelope evolution during the AGB phase of the
progenitor: a planet is tidally disrupted forming an accretion disk
around the central star, from which collimated bipolar outflows are
ejected, the other planet survives causing wobbling of the accretion
disk. The physical parameters and chemical abundances obtained from
our intermediate resolution spectrum are similar to those obtained in
previous analysis, with the abundances also pointing to a low-mass
progenitor for Me 2-1.
Description:
Narrow-band Hα, [NII] λ6583, [OIII] λ5007, [SII]
λ6731, and [OI] λ6300 images of Me2-1 were acquired on
July 24 and 25, 1997 using the HIRAC camera at the 2.56 m Nordic
Optical Telescope of the Observatorio de Roque de los Muchachos (ORM,
La Palma, Spain). Long-slit high-resolution spectroscopy on the
Hα, [NII] λ6583, and [OIII] λ5007 emission lines
of Me2-1 has been acquired on July 17, 2002, July 27 and 18, 2004, and
March 21, 2018 using the Manchester Echelle Spectrometer (MES) mounted
on the 2.1m telescope at the Observatorio Astronomico Nacional de San
Pedro Martir (OAN-SPM, Mexico). Intermediate-resolution long-slit
spectra of Me2-1 were obtained on August 13, 2004 using the Boller &
Chivens spectrograph mounted on the 2.1m telescope at the
Observatorio Astronomico Nacional de San Pedro Martir (OAN-SPM,
Mexico).
Spectra taken in binning 1x1 (spatial scale = 0.3 arcsec/pix) were
rebinned to binning 2x2 for the analysis to increase the S/N ratio.
Objects:
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RA (2000) DE Designation(s)
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15 22 19.28 -23 37 31.4 Me 2-1 = PN G342.1+27.5
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 161 16 List of fits images and spectra
fits/* . 16 Indivifual fits images and spectra
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 24 F5.3 arcsec/pix scale ? Scale of the image
26- 29 I4 --- Nx Number of pixels along X-axis
31- 34 I4 --- Ny ? Number of pixels along Y-axis
36- 45 A10 "date" Obs.date Observation date
47- 53 F7.2 0.1nm blambda ? Lower value of wavelength interval
for the spectra
55- 61 F7.2 0.1nm Blambda ? Upper value of wavelength interval
for the spectra
63- 71 F9.7 0.1nm dlambda ? Wavelength resolution for the spectra
73- 77 I5 Kibyte size Size of FITS file
79-108 A30 --- FileName Name of FITS file, in subdirectory fits
110-161 A52 --- Title Title of the FITS file
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Acknowledgements:
Luis F. Miranda, lfm(at)iaa.es
(End) Patricia Vannier [CDS] 02-May-2024