2010A&A...510A..36M


Query : 2010A&A...510A..36M

2010A&A...510A..36M - Astronomy and Astrophysics, volume 510, A36-36 (2010/2-1)

Polycyclic aromatic hydrocarbon processing in interstellar shocks.

MICELOTTA E.R., JONES A.P. and TIELENS A.G.G.M.

Abstract (from CDS):

PAHs appear to be an ubiquitous interstellar dust component but the effects of shocks waves upon them have never been fully investigated. We study the effects of energetic (≃0.01-1keV) ion (H, He and C) and electron collisions on PAHs in interstellar shock waves. We calculate the ion-PAH and electron-PAH nuclear and electronic interactions, above the threshold for carbon atom loss from a PAH, in 50-200km/s shock waves in the warm intercloud medium. Interstellar PAHs (NC=50) do not survive in shocks with velocities greater than 100km/s and larger PAHs (NC=200) are destroyed for shocks with velocities ≥125km/s. For shocks in the ≃75-100km/s range, where destruction is not complete, the PAH structure is likely to be severely denatured by the loss of an important fraction (20-40%) of the carbon atoms. We derive typical PAH lifetimes of the order of a fewx108yr for the Galaxy. These results are robust and independent of the uncertainties in some key parameters that have yet to be well-determined experimentally. The observation of PAH emission in shock regions implies that that emission either arises outside the shocked region or that those regions entrain denser clumps that, unless they are completely ablated and eroded in the shocked gas, allow dust and PAHs to survive in extreme environments.

Abstract Copyright:

Journal keyword(s): shock waves - dust, extinction - supernovae: general

Simbad objects: 7

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Number of rows : 7
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 SNR J052501-693842 SNR 05 25 02.3 -69 38 39           ~ 401 1
2 * zet Ori ** 05 40 45.52666 -01 56 33.2649 0.50 1.56 1.77 1.85 2.05 O9.7Ib+B0III 357 0
3 M 82 AGN 09 55 52.430 +69 40 46.93 9.61 9.30 8.41     ~ 5852 6
4 NGC 5529 GiP 14 15 34.226 +36 13 37.12   12.9       ~ 157 2
5 NGC 5906 GiG 15 15 53.687 +56 19 43.86   11.4       ~ 766 1
6 NGC 6618 OpC 18 20 47 -16 10.3           ~ 1612 0
7 3C 461 BL? 23 23 24.000 +58 48 54.00     14.30     ~ 2789 1

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