2011A&A...534A..19A


Query : 2011A&A...534A..19A

2011A&A...534A..19A - Astronomy and Astrophysics, volume 534A, 19-19 (2011/10-1)

Angle-dependent radiative grain alignment. Confirmation of a magnetic field - radiation anisotropy angle dependence on the efficiency of interstellar grain alignment.

ANDERSSON B.-G., PINTADO O., POTTER S.B., STRAIZYS V. and CHARCOS-LLORENS M.

Abstract (from CDS):

Interstellar grain alignment studies are currently experiencing a renaissance due to the development of a new quantitative theory based on radiative alignment torques (RAT). One of the distinguishing predictions of this theory is a dependence of the grain alignment efficiency on the relative angle (Ψ) between the magnetic field and the anisotropy direction of the radiation field. In an earlier study we found observational evidence for such an effect from observations of the polarization around the star HD 97300 in the Chamaeleon I cloud. However, due to the large uncertainties in the measured visual extinctions, the result was uncertain. By acquiring explicit spectral classification of the polarization targets, we have sought to perform a more precise reanalysis of the existing polarimetry data. We have obtained new spectral types for the stars in our for our polarization sample, which we combine with photometric data from the literature to derive accurate visual extinctions for our sample of background field stars. This allows a high accuracy test of the grain alignment efficiency as a function of Ψ. We confirm and improve the measured accuracy of the variability of the grain alignment efficiency with Ψ, seen in the earlier study. We note that the grain temperature (heating) also shows a dependence on Ψ which we interpret as a natural effect of the projection of the grain surface to the illuminating radiation source. This dependence also allows us to derive an estimate of the fraction of aligned grains in the cloud.

Abstract Copyright:

Journal keyword(s): polarization - dust, extinction - ISM: magnetic fields

Simbad objects: 38

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Number of rows : 38
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 Hen 3-545 Or* 10 59 06.9712894449 -77 01 40.309036535   12.91 11.136   9.596 K4Ve 193 0
2 TYC 9410-1931-1 * 10 59 29.1539525951 -76 11 15.569349651   12.763 11.542     G4III 3 0
3 CPD-75 701 * 10 59 39.8005758837 -76 24 15.616108728   11.71 11.16     G2V 3 0
4 CD-76 483 * 11 01 25.9310274411 -76 45 07.419155223   10.33 9.82     A9V 4 0
5 HD 95883 * 11 01 28.8311600626 -75 39 51.986843771   7.46 7.33     A2V(n) 14 0
6 Glass C TT* 11 03 11.5647749656 -77 21 04.319192459   12.59 11.48     G2V 25 0
7 CD-76 485 * 11 03 31.6852554489 -76 56 04.889988367   11.09 10.69     A2 3 0
8 TYC 9410-2633-1 PM* 11 03 36.3022141244 -75 59 03.473027159   11.34 10.75     G4V 2 0
9 TYC 9410-2362-1 * 11 04 10.2206562411 -76 22 18.195041393   11.64 10.88     A7V 3 0
10 TYC 9410-2504-1 PM* 11 04 37.9194261083 -76 19 00.868637703   12.03 11.36     F8V 3 0
11 TYC 9410-2172-1 * 11 04 43.7999003247 -76 16 45.176174663   12.38 11.46     F5V 3 0
12 TYC 9410-1907-1 * 11 06 07.5200189386 -75 55 09.143495804   11.680 10.569     F8III 3 0
13 NAME Cha 1 MoC 11 06 48 -77 18.0           ~ 1023 1
14 TYC 9410-2117-1 * 11 08 23.4105156024 -75 56 34.163429645   12.16 11.11     M2V 2 0
15 UCAC3 28-28907 * 11 09 07.6388199125 -76 18 14.595995699   13.337 11.375   9.29 K7III 5 0
16 HD 97300 Ae* 11 09 50.0178181814 -76 36 47.711452436   9.41 9.20   8.82 B9V 162 1
17 CD-75 526 * 11 12 50.7332609605 -75 58 06.937570770   10.33 9.81     F0 2 0
18 CD-75 527 * 11 12 54.8250455803 -75 52 11.940612829   10.53 9.14     K5 3 0
19 TYC 9410-2449-1 * 11 13 26.2959243629 -76 19 23.352583709   12.574 11.672     G2V 4 0
20 TYC 9414-649-1 * 11 13 48.0883109107 -77 50 12.374112702   12.496 11.324     G7III 4 0
21 GSC 09414-00462 * 11 14 09.3698032623 -77 14 49.490485650   12.68 10.89 10.64   K3III 5 0
22 TYC 9414-260-1 * 11 14 11.2120942759 -77 01 15.154914732   11.50 10.95     F2V 3 0
23 TYC 9414-392-1 PM* 11 14 29.6236035863 -77 07 06.414979478   11.94 11.18     G2V 4 0
24 TYC 9414-46-1 * 11 14 45.1378224065 -76 58 20.849427554   12.379 11.118     G4III 4 0
25 TYC 9410-1825-1 * 11 15 17.3258337814 -76 08 56.761023648   12.02 11.70     B9V 3 0
26 TYC 9410-2634-1 * 11 15 30.5594316035 -76 29 02.313921372   13.02 11.67     F8V 3 0
27 IRAS 11142-7612 * 11 15 57.3032524633 -76 29 08.533036776   13.276 11.291     M0III 6 0
28 IRAS 11158-7610 * 11 17 30.7851455688 -76 27 07.864128554   11.99 10.03   8.62 M3III 8 0
29 CD-76 492 * 11 18 19.8969249111 -77 07 16.673037650   11.098 9.979     G7III 4 0
30 TYC 9410-488-1 * 11 18 21.1773858472 -76 40 56.042960425   12.777 10.932     K6III 4 0
31 CD-74 611 * 11 19 54.7626007229 -75 38 38.204036473   10.82 10.26     A5 3 0
32 TYC 9415-403-1 * 11 20 07.1851062781 -76 55 23.984456566   12.15 11.68     A6V 2 0
33 TYC 9411-934-1 * 11 20 47.6964119223 -76 37 11.240409086   13.201 11.493     K4III 3 0
34 TYC 9411-1630-1 * 11 21 50.8511354305 -76 37 25.719302724   12.262 10.445     K4III 3 0
35 HD 99418 * 11 24 51.6694367171 -76 36 42.603946514   10.52 9.21     G8/K0(III) 11 0
36 HD 99558 Ro* 11 25 47.9497346745 -76 30 29.110862593   10.31 9.075   7.653 K0III 12 0
37 HD 99591 * 11 26 04.3386916295 -75 43 34.922602491   9.91 9.39     F7V 9 0
38 NAME Chamaeleon Region SFR 11 55 -78.0           ~ 717 0

    Equat.    Gal    SGal    Ecl

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2021.07.29-02:56:43

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