J/A+A/543/A39 ubvyβ photometry in Puppis-Vela (Franco, 2012)
Interstellar reddening towards six small areas in Puppis-Vela.
Franco G.A.P.
<Astron. Astrophys. 543, A39 (2012)>
=2012A&A...543A..39F 2012A&A...543A..39F
ADC_Keywords: Stars, nearby ; Photometry, uvby, beta
Keywords: stars: distances - ISM: clouds - dust, extinction -
ISM: individual object: Gum nebula - techniques: photometry
Abstract:
We investigate the distribution of the interstellar dust towards six
small volumes of the sky in the region of the Gum nebula. New
high-quality four-colour uvby and H-beta Stromgren photometry obtained
for 352 stars in six selected areas of Kapteyn, complemented with data
obtained in a previous investigation for two of these areas, were used
to estimate the colour excess and distance to these objects. The
obtained colour excess versus distance diagrams, complemented with
other information, when available, were analysed in order to infer the
properties of the interstellar medium permeating the observed volumes.
On the basis of the overall standard deviation in the photometric
measurements, we estimate that colour excesses and distances are
determined with an accuracy of 0.010mag and better than 30%,
respectively, for a sample of 520 stars. A comparison with 37 stars in
common with the new Hipparcos catalogue attests to the high quality of
the photometric distance determination. The obtained colour excess
versus distance diagrams testify to the low density volume towards the
observed lines-of-sight. Very few stars out to distances of 1kpc from
the Sun have colour excesses larger than E(b-y)=0.1mag. In spite of
the low density character of the interstellar medium towards the
Puppis-Vela direction, the obtained reddening as a function of the
distance indicates that two or more interstellar structures are
crossed towards the observed lines-of-sight. One of these structures
may be associated with the very low density wall of the Local Cavity,
which has a distance of 100-150pc from the Sun. Another structure
might be related to the Gum nebula, and if so, its front face would be
located at about 350pc from the Sun.
Description:
The observations were performed with the Stromgren Automatic Telescope
(SAT) of the Copenhagen Astronomical Observatory at La Silla, Chile.
The telescope was equipped with a six-channel uvby-beta
spectrograph-photometer, which allows simultaneous measurements for
the uvby passbands, or simultaneous measurements for the narrow and
wide passbands used to define the beta index.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 101 352 uvby-beta photometry for 352 stars earlier than
G0 in six selected areas of Kapteyn
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See also:
J/A+A/352/600 : O+B stars uvby-Hbeta photometry. I. (Kaltcheva+, 1999)
J/A+A/432/491 : CCD UBVIc photometry of Pismis 8 and Pismis 13 (Giorgi+, 2005)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 F8.4 --- Star Identification in the Potsdam Catalog (1)
10- 14 I5 --- HD ? Identification in the HD Catalog
16- 29 A14 --- SpType Michigan Classification (2)
31- 32 I2 h RAh Hour of Right Ascension (J2000)
34- 35 I2 min RAm Minute of Right Ascension (J2000)
37- 38 I2 s RAs Second of Right Ascension (J2000)
40 A1 --- DE- Sign of the Declination (J2000)
41- 42 I2 deg DEd Degree of Declination (J2000)
44- 45 I2 arcmin DEm Arcminute of Declination (J2000)
47- 48 I2 arcsec DEs Arcsecond of Declination (J2000)
50- 55 F6.3 mag Vmag V magnitude
57- 58 I2 mmag e_Vmag Uncertainty in Vmag
60- 65 F6.3 mag b-y Stromgren b-y colour index
67- 68 I2 mmag e_b-y Uncertainty in b-y
70- 75 F6.3 mag m1 Stromgren m1 colour index
77- 78 I2 mmag e_m1 Uncertainty in m1
80- 85 F6.3 mag c1 Stromgren c1 colour index
87- 88 I2 mmag e_c1 Uncertainty in c1
90 I1 --- Nn Number of nights in which the star observed
in uvby
92- 96 F5.3 mag Hb Hbeta index
98- 99 I2 mmag e_Hb Uncertainty in Hbeta
101 I1 --- o_Hb Number of nights in which the star observed
in Hbeta
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Note (1): Potsdam Spektral-Durchmusterung Catalog (Becker & Bruck 1929-1938,
1929POPot..27....1B 1929POPot..27....1B, 1930POPot..27....1B 1930POPot..27....1B, 1931POPot..27....1B 1931POPot..27....1B,
1938POPot..28....1B 1938POPot..28....1B, in Simbad)
Note (2): Michigan two-dimensional classification (Houk 1978, Cat. III/51,
1982, Cat. III/80)
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Acknowledgements:
G. Franco, franco(at)fisica.ufmg.br
(End) Patricia Vannier [CDS] 22-May-2012