J/A+A/410/905 Interstellar reddening parameter measurements (Patriarchi+, 2003)
A study of RV in galactic O stars from the 2MASS catalogue.
Patriarchi P., Morbidelli L., Perinotto M.
<Astron. Astrophys. 410, 905 (2003)>
=2003A&A...410..905P 2003A&A...410..905P
ADC_Keywords: Stars, O ; Photometry, infrared ; Interstellar medium ; Reddening
Keywords: ISM: dust, extinction
Abstract:
We present new measurements of the interstellar reddening parameter
RV=AV/E(B-V) towards 185 O stars, using J, H, Ks photometry from
the 2MASS project. The average RV from these is of 3.19±0.50. All
objects whose RV departs from this value by more than 2 sigma have
been recognized. Ten objects have RV higher than this value and two
lower. In the Cygnus region RV values follow the behaviour of the
general interstellar medium, while in the Carina arm, in spite of the
relatively larger distance, local cloud effects prevail. The
relatively few stars of our sample whose Hipparcos parallaxes are
reliable, are found to have distances systematically smaller than the
distances derived by the spectroscopic parallaxes. We argue that this
effect is consistent with the recently claimed discovery of grey
extinction towards OB stars.
Description:
The photometric data of the J, H, Ks filters of the 185 stars are
reported in Table 1 together with their photometric errors, as given
in the 2MASS catalogues. The quantity AV was then determined from
the J, H, Ks and V photometry using the method developed by Cardelli
et al. (1989ApJ...345..245C 1989ApJ...345..245C), who assumed that the shape of the IR
extinction law is invariant.
We report in Table 2 the full set of relevant quantities. From AV in
Table 2 and V in Table 1 we have derived the distances making use of
the calibration Mv vs. spectral type from Panagia
(1973AJ.....78..929P 1973AJ.....78..929P). The lines of sight with "anomalous" RV are
marked in Table 2 with "s" and "l" for small and large RV,
respectively.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 65 185 J, H, Ks photometry of O stars from 2MASS
table2.dat 74 185 Extinction parameters and distance from
spectroscopic parallax
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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2- 12 A11 --- Name Star identification
16- 20 F5.2 mag Vmag Visual magnitude
25- 29 F5.2 mag Jmag J magnitude (1)
32- 35 F4.2 mag e_Jmag Error of J magnitude
40- 44 F5.2 mag Hmag H magnitude (1)
47- 50 F4.2 mag e_Hmag Error of H magnitude
55- 59 F5.2 mag Ksmag Ks magnitude (1)
62- 65 F4.2 mag e_Ksmag Error of Ks magnitude
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Note (1): The above values come from the Point Source Catalogues of the
First and the Second Data Releases.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Star identification
12 A1 --- n_Name [*] Individual note (1)
14- 20 A7 --- SpType MK Spectral type
23- 26 F4.2 mag E(B-V) E(B-V) colour excess
32- 35 F4.2 mag Av Extinction at V
38- 41 F4.2 mag e_Av Error of Av
44- 47 F4.2 --- Rv Total-to-selective extinction ratio, Rv=Av/E(B-V)
50- 53 F4.2 --- e_Rv Error of Rv
57- 63 A7 --- Assoc Stellar association name
67- 70 F4.1 kpc Dist Distance derived from spectroscopic parallax
74 A1 --- u_Rv [sl] See Note (2)
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Note (1):
- HD 1337 is an eclipsing binary of Beta Lyr type and it is known
to have irregular variations. Polarization data indicate an envelope
possibly related to mass exchange.
- HD 35921 is an eclipsing binary of Beta Lyr type
Note (2): Flag for Rv values that depart the average value by more than
2 sigma: "s" when Rv<3.19-2*0.50, "l" when Rv>3.19+2*0.50
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Acknowledgements: Patrizio Patriarchi
(End) Patricia Bauer [CDS] 02-Sep-2003