2014A&A...570A.131V


Query : 2014A&A...570A.131V

2014A&A...570A.131V - Astronomy and Astrophysics, volume 570A, 131-131 (2014/10-1)

Eyes in the sky. Interactions between asymptotic giant branch star winds and the interstellar magnetic field.

VAN MARLE A.J., COX N.L.J. and DECIN L.

Abstract (from CDS):

The extended circumstellar envelopes (CSEs) of evolved low-mass stars display a large variety of morphologies. Understanding the various mechanisms that give rise to these extended structures is important to trace their mass-loss history. Here, we aim to examine the role of the interstellar magnetic field in shaping the extended morphologies of slow dusty winds of asymptotic giant branch (AGB) stars in an effort to pin-point the origin of so-called eye shaped CSEs of three carbon-rich AGB stars. In addition, we seek to understand if this pre-planetary nebula (PN) shaping can be responsible for asymmetries observed in PNe. Hydrodynamical simulations are used to study the effect of typical interstellar magnetic fields on the free-expanding spherical stellar winds as they sweep up the local interstellar medium (ISM).The simulations show that typical Galactic interstellar magnetic fields of 5 to 10µG are sufficient to alter the spherical expanding shells of AGB stars to appear as the characteristic eye shape revealed by far-infrared observations. The typical sizes of the simulated eyes are in accordance with the observed physical sizes. However, the eye shapes are transient in nature. Depending on the stellar and interstellar conditions, they develop after 20000 to 200000yrs and last for about 50000 to 500000yrs, assuming that the star is at rest relative to the local interstellar medium. Once formed, the eye shape develops lateral outflows parallel to the magnetic field. The explosion of a PN in the centre of the eye-shaped dust shell gives rise to an asymmetrical nebula with prominent inward pointing Rayleigh-Taylor instabilities. Interstellar magnetic fields can clearly affect the shaping of wind-ISM interaction shells. The occurrence of the eyes is most strongly influenced by stellar space motion and ISM density. Observability of this transient phase is favoured for lines-of-sight perpendicular to the interstellar magnetic field direction. The simulations indicate that shaping of the pre-PN envelope can strongly affect the shape and size of PNe.

Abstract Copyright:

Journal keyword(s): magnetohydrodynamics (MHD) - circumstellar matter - stars: AGB and post-AGB - ISM: bubbles - ISM: structure - ISM: magnetic fields

Simbad objects: 18

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Number of rows : 18
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 ACO 30 ClG 00 26 44 -12 11.4           ~ 12 1
2 ACO 70 ClG 00 37 20 -07 25.5           ~ 8 0
3 V* R Scl C* 01 26 58.0946233986 -32 32 35.437732667 17.26 9.59 5.72 3.69 2.30 C-N5+ 307 0
4 V* U Cam C* 03 41 48.1762532767 +62 38 54.397016016   11.5 11.00     C-N5 236 0
5 SH 2-216 PN 04 43 21.2636696575 +46 42 05.836016165   12.50 12.87 13.04   DAO.6 153 2
6 V* ST Cam C* 04 51 13.3478339517 +68 10 07.646494913   9.77 9.20     C-N5 140 0
7 * alf Ori s*r 05 55 10.30536 +07 24 25.4304 4.38 2.27 0.42 -1.17 -2.45 M1-M2Ia-Iab 1527 0
8 V* VY UMa C* 10 45 04.0305145913 +67 24 40.983504682 12.91 8.34 5.95 4.20 2.94 C-N5 193 0
9 V* R Crt AB* 11 00 33.8541158313 -18 19 29.574953304   10.33 9.80     M7/8III 202 0
10 PN MyCn 18 PN 13 39 35.0560904148 -67 22 51.758576199   13.30 12.54 13.19 12.61 ~ 271 1
11 V* V Pav C* 17 43 18.9385755525 -57 43 26.280846211   10.11 6.673 7.14 8.88 C6,4 63 0
12 NGC 6543 PN 17 58 33.4042519454 +66 37 58.748961810   11.09 11.28     [WC] 1135 1
13 M 57 PN 18 53 35.0969571234 +33 01 44.883146221   15.405 15.769 15.901 16.062 DA(O?) 798 2
14 NGC 6751 PN 19 05 55.5385116189 -05 59 32.291075445   15.78 15.48     [WC4] 322 0
15 V* W Aql S* 19 15 23.3581458294 -07 02 50.308513461   12.72 10.14     S6/6e 212 0
16 V* UX Dra C* 19 21 35.5158242859 +76 33 34.549597671   8.81 5.94     C-N5 193 0
17 NGC 6894 PN 20 16 23.965 +30 33 53.17           ~ 194 0
18 V* R Aqr Sy* 23 43 49.4629939776 -15 17 04.184232557   8.823 7.683 9.37   M6.5-8.5e 754 0

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2021.09.22-11:15:58

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