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J/A+A/275/549     Interstellar extinction curves    (Jenniskens+ 1993)

Environment dependence of interstellar extinction curves Jenniskens P., Greenberg J.M. <Astron. Astrophys. 275, 549 (1993)> =1993A&A...275..549J
ADC_Keywords: Extinction ; Photometry, ultraviolet Keywords: ISM: dust, extinction - ISM: HII regions - ISM: reflection nebulae - Ultraviolet: interstellar Abstract: The data are a decomposition of the extinction curves published by Aiello S., Barsella B., Chlewicki G., Greenberg J.M., Patriarchi P., and Perinotto M. (1988A&AS...73..195A) in the parameter scheme of Fitzpatrick E.L. and Massa D. (1988ApJ...328..734F). Each extinction curve k(x) = (A(lambda)-A(V))/(A(B)-A(V)) is given by: k(x) = c1 + c2*x + c3* D(x,x0,y) + c4*F(x) Where x = 1/wavelength (in inverse micron), D is a Drude profile: D(x,x0,y) = x2/((x2-x02)2 + y2x2) and F is a polynomial of order 3: F(x) = 0.05392(x-5.9)2 + 0.0564(x-5.9)3 for 5.9<x<8.0 F(x) = 0 for x<5.9 In this scheme the parameters have the following meaning: c1: related directly to c2 because of normalisation k(x) c2: slope of the linear rise ( mag/E(B-V) ) y: width of the bump (inverse micron) c3: c3/y2 is bump height, pi*c3/(2.*y) is bump area x0: position of the bump (inverse micron) c4: amount of FUV non-linear rise contribution: at 8 mu-1: 2.9c4 (mag/E(B-V)) | * ^ | * 2.9c4 | ^ * * k(x)| c3/y^2 * * * .. v | *< y >* *.. | v * .. * * | *.. c2 1 | * 0 | * |^ * |Rv * |v|_ V B x0 5.9 8.0 x=1/wavelength (1/micron) Values of Rv, the ratio of total to selective extinction, can be found in Aiello et al. (1988A&AS...73..195A). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table 68 115 Extinction coefficients
Byte-by-byte Description of file: table
Bytes Format Units Label Explanations
1- 11 A11 --- starname Designation of star. 13- 16 F4.2 --- k(U) ? Extinction in U band 19- 23 F5.2 --- c1 Coefficient (see text) 24- 28 F5.2 um c2 Coefficient (see text) 29- 33 F5.2 --- c3 Coefficient (see text) 34- 38 F5.2 --- c4 Coefficient (see text) 40- 43 F4.2 um-1 y Width of the bump 45- 49 F5.3 um-1 x0 Position of the bump 52- 56 F5.3 --- chisq Indication of the deviation between fitted curve and actual data 59 I1 --- Q Quality indication of the data (1) 61 I1 --- IPSC [0/2] IRAS point source classification (2) 66- 68 A3 --- TYPE Environment characterisation from IRAS Skyflux maps (3)
Note (1): The quality are: Q=1 gives a bad fit to the U band extinction, due to saturation at long wavelength, and spectra marked Q=2 show signs of underexposure in the bump. Note (2): IPSC classification as (for IPSC>0): IPSC=1 is point source with 12 micron flux smaller than 25, IPSC=2 is point source with 25 micron flux smaller than 12. Note (3): the characterisation takes the following values: CS: circumstellar DIF: diffuse medium line of sight (no aparent heating) BUB: bubble, extended region of increased 60/100 around OB association HII: HII region, compact regions of highly increased 60/100 REF: reflection nebulae, small compact regions of highly increased 60/100 associated with B type stars.

(End) Patricia Bauer [CDS] 10-Sep-1993
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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