J/A+A/658/A17 Post-common-envelope PN and mol. mass (Santander-Garcia+, 2022)
The ionised and molecular mass of post-common-envelope planetary nebulae.
The missing mass problem.
Santander-Garcia M., Jones D., Alcolea J., Bujarrabal V., Wesson R.
<Astron. Astrophys. 658, A17 (2022)>
=2022A&A...658A..17S 2022A&A...658A..17S (SIMBAD/NED BibCode)
ADC_Keywords: Planetary nebulae ; Carbon monoxide ; Photometry, H-alpha
Keywords: planetary nebulae: general - planetary nebulae: individual: NGC 6778 -
circumstellar matter - binaries: close - stars: mass-loss -
stars: winds, outflows
Abstract:
Most planetary nebulae (PNe) show beautiful, axisymmetric morphologies
despite their progenitor stars being essentially spherical. Close
binarity is widely invoked to help eject an axisymmetric nebula, after
a brief phase of engulfment of the secondary within the envelope of
the Asymptotic Giant Branch (AGB) star, known as the common envelope
(CE). The evolution of the AGB would thus be interrupted abruptly, its
still quite massive envelope being rapidly ejected to form the PN,
which a priori would be more massive than a PN coming from the same
star, were it single. We aim at testing this hypothesis by
investigating the ionised and molecular masses of a sample consisting
of 21 post-CE PNe, roughly one fifth of the known total population of
these objects, and comparing them to a large sample of 'regular' (i.e.
not known to arise from close-binary systems) PNe. We have gathered
data on the ionised and molecular content of our sample from the
literature, and carried out molecular observations of several
previously unobserved objects. We derive the ionised and molecular
masses of the sample by means of a systematic approach, using
tabulated, dereddened H-beta fluxes for finding the ionised mass, and
12CO J=2-1 and J=3-2 observations for estimating the molecular mass.
There is a general lack of molecular content in post-CE PNe. Our
observations only reveal molecule-rich gas around NGC 6778,
distributed into a low-mass, expanding equatorial ring lying beyond
the ionised broken ring previously observed in this nebula. The only
two other objects showing molecular content (from the literature) are
NGC 2346 and NGC 7293. Once we derive the ionised and molecular
masses, we find that post-CE PNe arising from Single-Degenerate (SD)
systems are just as massive, on average, as the 'regular' PNe sample,
whereas post-CE PNe arising from Double-Degenerate (DD) systems are
considerably more massive, and show substantially larger linear
momenta and kinetic energy than SD systems and `regular' PNe.
Reconstruction of the CE of four objects, for which a wealth of data
on the nebulae and complete orbital parameters are available, further
suggests that the mass of SD nebulae actually amounts to a very small
fraction of the envelope of their progenitor stars. This leads to the
uncomfortable question of where the rest of the envelope is and why we
cannot detect it in the stars' vicinity, thus raising serious doubts
on our understanding of these intriguing objects.
Description:
Table 4: Ionised and molecular masses of a sample of 21
Single-Degenerate (SD) and Double-Degenerate (DD) post-common-envelope
planetary nebulae (PNe)
Table A.1: Ionised and molecular masses of a sample of 97 'regular'
(not know to arise from close-binary systems) PNe
Table B.1: Electron densities, temperatures, distances, sizes (major
axes), expansion velocities, H-alpha dereddened fluxes, and 12CO
emission for all the samples used in the analysis (SD, DD and
'regular' PNe).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 99 21 Computed ionised and molecular masses of
post-common-envelope PNe
tablea1.dat 99 97 Computed ionised and molecular masses of
the regular comparison sample
tableb1.dat 240 118 Parameters used to estimate the masses of the
whole sample
refs.dat 114 74 References
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Byte-by-byte Description of file: table4.dat tablea1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- PNG Galactic PN designation
15- 28 A14 --- Name Common PN name
32- 37 F6.3 kpc Dist Distance to the PN
41- 45 F5.3 kpc E_Dist Positive (upper) error on distance
49- 53 F5.3 kpc e_Dist Negative (lower) error on distance
57- 61 F5.3 Msun Mion Ionised mass
65- 70 F6.3 Msun E_Mion Positive (upper) error on ionised mass
74- 79 F6.3 Msun e_Mion Negative (lower) error on ionised mass
83 A1 --- l_Mmol [<] Upper limit flag on Mmol
87- 91 F5.3 Msun Mmol Molecular mass (or upper limit, see flag)
95- 99 F5.3 Msun e_Mmol ? Error on molecular mass, only if
Mmol is not an upper limit
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Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Common PN name
18- 22 I5 cm-3 n Electronic density
26- 30 I5 cm-3 E_n ? Positive (upper) error on density
34- 38 I5 cm-3 e_n ? Negative (lower) error on density
42- 46 F5.2 kK Te Electronic temperature (1)
50- 53 F4.2 kK E_Te ? Positive (upper) error on temperature
57- 60 F4.2 kK e_Te ? Negative (lower) error on temperature
64- 69 F6.3 kpc Dist Distance to the PN
73- 77 F5.3 kpc E_Dist Positive (upper) error on distance
81- 85 F5.3 kpc e_Dist Negative (lower) error on distance
89- 93 F5.1 arcsec Diama PN diameter along major axis
97-101 F5.1 arcsec Diamb PN diameter along minor axis
105-109 F5.1 km/s vexp ? PN characteristic expansion velocity
113-117 F5.2 [mW/m2/sr] logS(Ha) Logarithm of H-alpha dereddened flux
121-124 F4.2 [mW/m2/sr] e_logS(Ha) Error on the logarithmic H-alpha flux
128-135 A8 --- Tel Telescope used for CO observations
139-141 A3 --- Trans CO rotational (J) transition used
145-149 F5.1 mK rms ? Sensitivity on CO non-detection
153-157 F5.1 K.km/s Int ? CO intensity on single-pointing
161-167 E7.1 K.km/s.arcsec2 Flux ? CO total flux
171-248 A78 --- Ref References (in refs.dat file)
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Note (1): Te assumed to be 10kK when no data available in the literature
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref Reference code
4- 22 A19 --- BibCode BibCode
24- 51 A28 --- Aut Authors' name
52-114 A63 --- Com Comments
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Acknowledgements:
Miguel Santander-Garcia, m.santander(at)oan.es
(End) Miguel Santander-Garcia [OAN], Patricia Vannier [CDS] 08-Nov-2021