J/ApJ/705/509 High-dispersion spectrum of the PN DdDm 1 (Otsuka+, 2009)
High-dispersion spectrum of the halo planetary nebula DdDm 1.
Otsuka M., Hyung S., Lee S.-J., Izumiura H., Tajitsu A.
<Astrophys. J., 705, 509-528 (2009)>
=2009ApJ...705..509O 2009ApJ...705..509O
ADC_Keywords: Planetary nebulae ; Spectroscopy ; Line Profiles
Keywords: planetary nebulae: individual (DdDm 1) - ISM: abundances -
ISM: evolution - stars: Population II
Abstract:
Using the High Dispersion Spectrograph (HDS) at the Subaru Telescope,
we secured the high-resolution line spectra in the 3600-7500Å
wavelength range of the Galactic halo planetary nebula DdDm 1. We also
analyzed the Hubble Space Telescope Faint Object Spectrograph data in
the 1200-6730Å wavelength range. The diagnostic results indicate
the electron temperatures of Tε∼11000-14000K and the
electron number densities of Nε∼2000-10500cm-3. In spite
of high gaseous temperatures, we have not detected high excitation
lines, e.g., HeII. We derived abundance based on the ionic
concentration of permitted and forbidden lines and the photoionization
model. A comparison of the ionic concentrations from forbidden lines
to recombination lines shows the abundance discrepancy between them.
We tested various possibilities, e.g., temperature fluctuation and
high-density blob components, to explain the discrepancy. The
high-density components or density fluctuation might be partly
responsible for the discrepancy. DdDm 1 shows a low carbon abundance
that corresponds to metal-poor stars, [Fe/H]≤-1. Assuming a distance
of 10kpc to DdDm 1, theoretical models suggest that the central star
has Teff∼39000K and L∼2000-3000L☉. The relatively high gas
temperatures appear to be caused by very low heavy elemental
abundances or insufficient coolants in the shell gas. Its progenitor,
born in an extremely carbon-poor environment as an initial mass of
about 0.9M☉, had probably experienced only the first dredge-up.
Description:
Our observations were made with High Dispersion Spectrograph (HDS),
attached to one of the two Nasmyth foci of the Subaru 8.2m telescope
atop Mauna Kea, Hawaii, on 2005 September 18.
HST/Faint Object Spectrograph (FOS) observations were obtained from
1995 Oct 9 archives.
We obtained the spectra in the 3600-7500Å range from two settings:
(1) setting #1-2 in 3600-5300Å with the blue cross disperser ; and
(2) setting #3-4 in 4800-7500Å with the red cross disperser. Since
both #1-2 and #3-4 settings overlapped in the 4800-5300Å, we would
be able to scale two settings using the common spectra, such as
Hβ, [OIII]4959/5007.
Objects:
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RA (2000) DE Designation(s) Radial Velocity (this work)
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16 40 18.2 +38 42 20 DdDm 1 = PN G061.9+41.3 -309.14 ± 1.22
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 59 177 *Observed line intensities [F(Hβ)=100] and
identifications
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Note on table4.dat: We obtained the two different spectral ranges covered
in the spectra that have overlapping regions (Δλ∼300Å)
at the edges. The final intensity of a given line in the overlapping
regions is the average of the values obtained in both spectra.
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See also:
B/mk : Catalogue of Stellar Spectral Classifications (Skiff, 2010)
B/hst : HST Archived Exposures Catalog (STScI, 2007)
IV/24 : Catalogue of Galactic Planetary Nebulae (Kohoutek, 2001)
V/84 : Strasbourg-ESO Catalogue of Galactic Planetary Nebulae (Acker+, 1992)
J/PAZh/35/574 : He, C, N and O abundances in planetary nebulae (Milanova+,
2009)
J/A+A/475/217 : Classification of planetary nebulae (Quireza+, 2007)
J/MNRAS/349/793 : Galactic PNe abundances (Perinotto+, 2004)
J/A+A/408/1029 : Coordinates of Galactic planetary nebulae (Kerber+, 2003)
J/AZh/74/853 : Distances and physical parameters of PNe (Mal'kov, 1997)
J/A+AS/94/399 : Absolute fluxes and distances of PN (Cahn+, 1992)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 7 F7.2 0.1nm lam(L) Laboratory wavelength in Angstroms
9- 16 A8 --- Ion The ion of the most probable identification
18- 21 A4 --- Mult Multiplet number
23- 29 F7.2 0.1nm lam(O) ? Measured wavelength, λ(obs),
corrected for radial velocity
31 I1 --- f_lam(O) [1,3]? 1= blue- or 2= red- shifted line
components when they are separable; 3= second
red-
33- 39 F7.3 --- Flux ? Normalized line intensity, F(λ) (1)
41- 45 F5.3 --- e_Flux ? 1σ error in Flux
47- 53 F7.3 --- Ftot ? Normalized total line intensity when
components were separated
55- 59 F5.3 --- e_Ftot ? FTot uncertainty
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Note (1): F(Hβ)∼1.87x10-12erg/cm2/s = 1.87fW/m2
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 07-Feb-2012