J/AJ/107/1577 Halo red giants reddening (Anthony-Twarog+, 1994)
Reddening estimation for halo red giants using uvby photometry ANTHONY-TWAROG B.J., TWAROG B.A. <Astron. J. 107, 1577 (1994)> =1994AJ....107.1577A (SIMBAD/NED Reference)
Abstract: Updated uvby observations for a larger sample of metal-deficient red giants are presented and combined with a select sample of data from the literature transformed to a common system. Using the reddening maps of Burstein & Heiles [AJ, 87, 1165 (1982)], new absolute magnitudes, distances, metallicities, and reddenings are derived for each star. The metallicities are determined with a revised calibration of the m1, (b-y) diagram based upon comparison to a compilation of recent spectroscopic abundances transformed to a common system. The photometric abundances agree very well with the spectroscopic; the dispersion among the residuals for 58 giants is ±0.16dex. The dereddened indices are used to show that for red giants with [Fe/H]←1.5, there is a well-defined relation in the c0, (b-y)0 diagram which exhibits only a weak dependence upon metallicity. Use of the standard relations allows one to obtain reddening estimates for normal halo field giants and globular clusters in the appropriate metallicity range. Addresses: Anthony-Twarog B.J. and Twarog B.A. Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas 66045-2151 File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1 68 114 uvby photometry of metal-deficient giants table5a 53 114 Derived parameters from table1
Byte-by-byte Description of file: table1
Bytes Format Units Label Explanations
1- 9 A9 --- ID Identification (1) 11- 16 F6.3 mag V Visual magnitude 18- 22 F5.3 mag e_V Standard deviation in V (2) 24- 28 F5.3 mag b-y b-y color index on the Stromgren system 30- 34 F5.3 mag e_b-y Standard deviation in b-y (2) 36- 37 I2 --- o_b-y Number of observations for V and b-y (3) 39- 43 F5.3 mag m1 m1 index 45- 49 F5.3 mag e_m1 Standard deviation in m1 (2) 51- 55 F5.3 mag c1 c1 index 57- 61 F5.3 mag e_c1 Standard deviation in c1 (2) 63- 64 I2 --- o_c1 Number of observations for m1 and c1 (3) 65- 66 I2 --- Note [ 1-2]? Note flag (4)
Note (1): Henry Draper, Durchmusterung, or other identification. See explanation of 'Note' field. Note (2): Errors listed for the magnitude and the indices are standard deviations for a single observation; the standard deviations have been set to 0.000 for stars with only one observation (in field o_b-y or o_c1). It should be emphasized that the probable photometric errors for the stars with V>13.0 and only one observation are significantly larger than implied by the brighter stars. Note (3): Because the stars were also included in the Caby photometric program (Anthony-Twarog et al. 1991, AJ, 101, 1902), many of the stars have a larger number of V and (b-y) (field N1) than m1 and c1 (field N2). Note (4): 1 - Identification from Beers et al. 1992, AJ, 103, 1987. 2 - Identification from Beers et al. 1992, AJ, 103, 1987. This star is a brighter giant located near a potential metal-deficient program star; its approximate coordinates are: RA(1950.0) = 23h 24m 00s; DEC(1950.0) = -02d 55m 58s. The actual program star proved to be too faint to produce reliable photometry.
Byte-by-byte Description of file: table5a
Bytes Format Units Label Explanations
1- 9 A9 --- ID Identification 11 A1 --- n_E(b-y) [ *] Note for derived reddening (1) 13- 17 F5.3 mag E(b-y) ? Reddening 20- 24 F5.2 mag Mv ? Absolute magnitude 26- 30 I5 pc R ? Distance 32 A1 --- l_[Fe/H] Limit flag for [Fe/H] 33- 37 F5.2 Sun [Fe/H] Metallicity 40- 44 F5.2 Sun [Fe/H]SP ? Average spectroscopic abundance 48- 51 F4.2 Sun e_[Fe/H]SP ? Dispersion in [Fe/H]SP 53 I1 --- N ? Number of estimates included in [Fe/H]SP
Note (1): An asterisk, '*', indicates that the derived reddening, E(b-y) is from comparisons to the standard c0,(b-y)0 relations, as described in Section 4.3 of the printed paper.
Origin: AAS CD-ROM series, Volume 2, 1994
(End) Lee Brotzman [ADS] 08-May-1994, Patricia Bauer [CDS] 24-Oct-1994
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