J/AJ/114/699 J/AJ/114/699 Spectrophotometry in open clusters L Clampitt D Burstein Astron. J. 114 699 1997 1997AJ....114..699C I/68 : Positions & Proper Motions in alpha Per (Fresneau 1980) I/163 : US Naval Observatory Pleiades Catalog (Van Flandern 1969) J/MNRAS/257/257 : Proper motions in the Hyades (Reid 1992) III/55 : Radial Velocities in Open Clusters (Mermilliod 1979) II/194 : Photometric study of IC 4665 (McCarthy+ 1969) J/AJ/105/1441 : IC 4665 (Prosser 1993) I/203 : NGC 7092 region PM, UBV-phot and SpClass (Platais 1994) J/other/AcASn/32.176 : Stars of Praesepe (Wang+ 1991) Clusters, open Photometry, uvby Spectrophotometry The final calibrated spectral energy distributions (SEDs; relative to 5556{AA}) for all 237 stars are given in Table 4 according to the cluster identification number, the star HD or BD number, and the night(s) of observation. Table 6 lists the observed B-V and uvby data as obtained from SIMBAD, together with the differences (observed minus predicted) between the colors predicted from the authors' spectrophotometry and the observed colors. Spectrophotometry is presented for 237 stars in 7 nearby open clusters: Hyades, Pleiades, Alpha Persei, Praesepe, Coma Berenices, IC 4665, and M39. The observations were taken by Lee McDonald and David Burstein using the Wampler single-channel scanner on the Crossley 0.9m telescope at Lick Observatory from 1973 July through 1974 December. Sixteen bandpasses spanning the spectral range 3500-7780{AA} were observed for each star, with bandwidths 32, 48, or 64{AA}. Data are standardized to the Hayes-Latham system to mutual accuracy of 0.016mag per passband. The accuracy of the spectrophotometry is assessed in three ways on a star-by-star basis. First, comparisons are made with previously published spectrophotometry for 19 stars observed in common. Second, (B-V) colors and uvby colors are compared for 236 stars and 221 stars, respectively. Finally, comparisons are made for 200 main sequence stars to the spectral synthesis models of Kurucz, fixing logg=4.0 and [Fe/H]=0.0, and only varying effective temperature. The accuracy of tests using uvby colors and the Kurucz models are shown to track each other closely, yielding an accuracy estimate (1{sigma}) of 0.01mag for the 13 colors formed from bandpasses longward of the Balmer jump, and 0.02mag for the 3 colors formed from the three bandpasses below the Balmer jump. In contrast, larger scatter is found relative to the previously published spectrophotometry of Bohm-Vitense & Johnson (1977ApJS...35..461B) (16 stars in common) and Gunn & Stryker (1983, Cat. <III/88>) (3 stars). We also show that the scatter in the fits of the spectrophotometric colors and the uvby filter colors is a reasonable way to identify the observations of which specific stars are accurate to 1{sigma}, 2{sigma}, .... As such, the residuals from both the filter color fits and the Kurucz model fits are tabulated for each star where it was possible to make a comparison, so users of these data can choose stars according to the accuracy of the data that is appropriate to their needs. The very good agreement between the models and these data verifies the accuracy of these data, and also verifies the usefulness of the Kurucz models to define spectrophotometry for stars in this temperature range (>5000K). These data define accurate spectrophotometry of bright, open cluster stars that can be used as a secondary flux calibration for CCD-based spectrophotometric surveys. (c) 1997 American Astronomical Society.

ID Star identification number number=1 Number of star according to the following sources: Hyades (Hya): Van Bueren, 1952BAN....11..385V Pleiades (Ple): Hertzsprung, E., 1947AnLei..19a...1H alpha Per (Per): Heckmann, O. et al. 1956AN....283..109H Praesepe (Pra): Klein-Wassink, W. J., 1927PGro...41....1K Coma Berenices (Com): Trumpler, F. J., 1938LicOB..18..167T IC 4665 (IC4): Kopff, 1943AN....274...69K M39 (M39): Ebbinghausen, E. G., 1940ApJ....92..434E --- Night Nights observed number=2 Night of observation + secondary standard star(s) used for night 1 Jul 17/18, 1973 M39 M39 33 2 Aug 14/15, 1973 Pleiades Ple 785 3 Aug 15/16, 1973 M39,alpha Persei Per 605 4 Sep 15/16, 1973 Pleiades Ple 785 5 Sep 16/17, 1973 Hyades Hya 56 6 Sep 17/18, 1973 alpha Persei,Pleiades Ple 785 7 Sep 18/19, 1973 Pleiades Ple 785 8 Sep 20/21, 1973 Hyades Hya 56 9 Oct 12/13, 1973 Hyades Hya 56 10 Oct 13/14, 1973 Hyades Hya 56 11 Mar 8/ 9, 1974 Hyades,Praesepe,Coma B. Hya 56 12 Mar 9/10, 1974 Coma B. Com 60 13 Apr 10/11, 1974 Praesepe Pra 300 14 May 6/ 7, 1974 Coma B. Com 60 15 May 7/ 8, 1974 Praesepe,Coma B.,IC 4665 Pra 300,Com 60 16 Aug 9/10, 1974 IC 4665 IC4 62 17 Dec 29/30, 1974 Hyades,Pleiades,alpha Persei Hya 56 stan If star is used as secondary standard for that cluster --- 3500 3500-5556 color number=4 Spectrophotometric colors of the cited filter formed with the 5556 filter (15 colors). All colors are expressed in terms of 0.0001 magnitudes (e.g., a value of 1225 is a color of 1.225mag). mmag u_3500 indicates larger error in color number=3 Indicator if error of observation known to be larger than typical error : = error of 0.03-0.06 mag; * = interpolated value from star color and bracketing observations. --- 3571 3571-5556 color number=4 Spectrophotometric colors of the cited filter formed with the 5556 filter (15 colors). All colors are expressed in terms of 0.0001 magnitudes (e.g., a value of 1225 is a color of 1.225mag). mmag u_3571 indicates larger error in color number=3 Indicator if error of observation known to be larger than typical error : = error of 0.03-0.06 mag; * = interpolated value from star color and bracketing observations. --- 3636 3636-5556 color number=4 Spectrophotometric colors of the cited filter formed with the 5556 filter (15 colors). All colors are expressed in terms of 0.0001 magnitudes (e.g., a value of 1225 is a color of 1.225mag). mmag u_3636 indicates larger error in color number=3 Indicator if error of observation known to be larger than typical error : = error of 0.03-0.06 mag; * = interpolated value from star color and bracketing observations. --- 4036 4036-5556 color number=4 Spectrophotometric colors of the cited filter formed with the 5556 filter (15 colors). All colors are expressed in terms of 0.0001 magnitudes (e.g., a value of 1225 is a color of 1.225mag). mmag u_4036 indicates larger error in color number=3 Indicator if error of observation known to be larger than typical error : = error of 0.03-0.06 mag; * = interpolated value from star color and bracketing observations. --- 4167 4167-5556 color number=4 Spectrophotometric colors of the cited filter formed with the 5556 filter (15 colors). All colors are expressed in terms of 0.0001 magnitudes (e.g., a value of 1225 is a color of 1.225mag). mmag u_4167 indicates larger error in color number=3 Indicator if error of observation known to be larger than typical error : = error of 0.03-0.06 mag; * = interpolated value from star color and bracketing observations. --- 4255 4255-5556 color number=4 Spectrophotometric colors of the cited filter formed with the 5556 filter (15 colors). All colors are expressed in terms of 0.0001 magnitudes (e.g., a value of 1225 is a color of 1.225mag). mmag u_4255 indicates larger error in color number=3 Indicator if error of observation known to be larger than typical error : = error of 0.03-0.06 mag; * = interpolated value from star color and bracketing observations. --- 4400 4400-5556 color number=4 Spectrophotometric colors of the cited filter formed with the 5556 filter (15 colors). All colors are expressed in terms of 0.0001 magnitudes (e.g., a value of 1225 is a color of 1.225mag). mmag u_4400 indicates larger error in color number=3 Indicator if error of observation known to be larger than typical error : = error of 0.03-0.06 mag; * = interpolated value from star color and bracketing observations. --- 4565 4565-5556 color number=4 Spectrophotometric colors of the cited filter formed with the 5556 filter (15 colors). All colors are expressed in terms of 0.0001 magnitudes (e.g., a value of 1225 is a color of 1.225mag). mmag u_4565 indicates larger error in color number=3 Indicator if error of observation known to be larger than typical error : = error of 0.03-0.06 mag; * = interpolated value from star color and bracketing observations. --- 4785 4785-5556 color number=4 Spectrophotometric colors of the cited filter formed with the 5556 filter (15 colors). All colors are expressed in terms of 0.0001 magnitudes (e.g., a value of 1225 is a color of 1.225mag). mmag u_4785 indicates larger error in color number=3 Indicator if error of observation known to be larger than typical error : = error of 0.03-0.06 mag; * = interpolated value from star color and bracketing observations. --- 5000 5000-5556 color number=4 Spectrophotometric colors of the cited filter formed with the 5556 filter (15 colors). All colors are expressed in terms of 0.0001 magnitudes (e.g., a value of 1225 is a color of 1.225mag). mmag u_5000 indicates larger error in color number=3 Indicator if error of observation known to be larger than typical error : = error of 0.03-0.06 mag; * = interpolated value from star color and bracketing observations. --- 5263 5263-5556 color number=4 Spectrophotometric colors of the cited filter formed with the 5556 filter (15 colors). All colors are expressed in terms of 0.0001 magnitudes (e.g., a value of 1225 is a color of 1.225mag). mmag u_5263 indicates larger error in color number=3 Indicator if error of observation known to be larger than typical error : = error of 0.03-0.06 mag; * = interpolated value from star color and bracketing observations. --- 5840 5840-5556 color number=4 Spectrophotometric colors of the cited filter formed with the 5556 filter (15 colors). All colors are expressed in terms of 0.0001 magnitudes (e.g., a value of 1225 is a color of 1.225mag). mmag u_5840 indicates larger error in color number=3 Indicator if error of observation known to be larger than typical error : = error of 0.03-0.06 mag; * = interpolated value from star color and bracketing observations. --- 6300 6300-5556 color number=4 Spectrophotometric colors of the cited filter formed with the 5556 filter (15 colors). All colors are expressed in terms of 0.0001 magnitudes (e.g., a value of 1225 is a color of 1.225mag). mmag u_6300 indicates larger error in color number=3 Indicator if error of observation known to be larger than typical error : = error of 0.03-0.06 mag; * = interpolated value from star color and bracketing observations. --- 6710 6710-5556 color number=4 Spectrophotometric colors of the cited filter formed with the 5556 filter (15 colors). All colors are expressed in terms of 0.0001 magnitudes (e.g., a value of 1225 is a color of 1.225mag). mmag u_6710 indicates larger error in color number=3 Indicator if error of observation known to be larger than typical error : = error of 0.03-0.06 mag; * = interpolated value from star color and bracketing observations. --- 7100 7100-5556 color number=4 Spectrophotometric colors of the cited filter formed with the 5556 filter (15 colors). All colors are expressed in terms of 0.0001 magnitudes (e.g., a value of 1225 is a color of 1.225mag). mmag u_7100 indicates larger error in color number=3 Indicator if error of observation known to be larger than typical error : = error of 0.03-0.06 mag; * = interpolated value from star color and bracketing observations. --- 7400 7400-5556 color number=4 Spectrophotometric colors of the cited filter formed with the 5556 filter (15 colors). All colors are expressed in terms of 0.0001 magnitudes (e.g., a value of 1225 is a color of 1.225mag). mmag u_7400 indicates larger error in color number=3 Indicator if error of observation known to be larger than typical error : = error of 0.03-0.06 mag; * = interpolated value from star color and bracketing observations. --- ID Star identification number number=1 Number of star according to the following sources: Hyades (Hya): Van Bueren, 1952BAN....11..385V Pleiades (Ple): Hertzsprung, E., 1947AnLei..19a...1H alpha Per (Per): Heckmann, O. et al. 1956AN....283..109H Praesepe (Pra): Klein-Wassink, W. J., 1927PGro...41....1K Coma Berenices (Com): Trumpler, F. J., 1938LicOB..18..167T IC 4665 (IC4): Kopff, 1943AN....274...69K M39 (M39): Ebbinghausen, E. G., 1940ApJ....92..434E --- HD HD number of star --- RAh Right Ascension 1950 from SIMBAD h --- Always ':' --- RAm Right Ascension 1950 from SIMBAD min --- Always ':' --- RAs Right Ascension 1950 from SIMBAD s DE- Declination sign --- DEd Declination 1950 from SIMBAD deg --- Always ':' --- DEm Declination 1950 from SIMBAD arcmin --- Always ':' --- DEs Declination 1950 from SIMBAD arcsec Sp Spectral type from SIMBAD number=2 Spectral type from SIMBAD. A colon on either spectral class or luminosity class indicates uncertainty. --- Notes Notes for particular stars number=3 Data come from SIMBAD unless a note is given. The note code is: c: these stars are variable according to SIMBAD d: Luminosity class taken from Mendoza, E. E. 1967BOTT....4..149M e: Spectral class taken from Crawford & Barnes 1972AJ.....77..862C f: Luminosity class taken from Crawford & Barnes, 1972AJ.....77..862C --- Vmag Apparent V mag from SIMBAD mag B-V 9.999? Observed B-V color from SIMBAD mag u-b 9.999? Observed u-b color from SIMBAD mag v-y 9.999? Observed v-y color from SIMBAD mag b-y 9.999? Observed b-y color from SIMBAD mag dB-V 9.999? B-V color diff, US-SIMBAD number=4 The residuals from comparing the spectrophotometric colors with B-V, u-b, v-y, b-y colors from SIMBAD. The color transformations are as follows: Color Transformation Slope Z.P. error Johnson B-V Matthews & Sandage 1.072 0.433 0.021 (1963ApJ...138...30M) Stromgren u-b 3500 - (4565+4785)/2 1.005 0.125 0.024 Stromgren b-y (4565+4785)/2 0.934 0.153 0.013 Stromgren v-y (4036+4167)/2 0.891 0.415 0.032 The color transformation for B-V was done using the airmass = 1 bandpass functions for B and V mag as given by Matthews & Sandage mag du-b 9.999? u-b color diff, US-SIMBAD number=4 The residuals from comparing the spectrophotometric colors with B-V, u-b, v-y, b-y colors from SIMBAD. The color transformations are as follows: Color Transformation Slope Z.P. error Johnson B-V Matthews & Sandage 1.072 0.433 0.021 (1963ApJ...138...30M) Stromgren u-b 3500 - (4565+4785)/2 1.005 0.125 0.024 Stromgren b-y (4565+4785)/2 0.934 0.153 0.013 Stromgren v-y (4036+4167)/2 0.891 0.415 0.032 The color transformation for B-V was done using the airmass = 1 bandpass functions for B and V mag as given by Matthews & Sandage mag n_du-b Bad u-b color comparision number=5 If indicated by a colon (:), this color comparison was not used in determining the color transformations. --- dv-y 9.999? v-y color diff, US-SIMBAD number=4 The residuals from comparing the spectrophotometric colors with B-V, u-b, v-y, b-y colors from SIMBAD. The color transformations are as follows: Color Transformation Slope Z.P. error Johnson B-V Matthews & Sandage 1.072 0.433 0.021 (1963ApJ...138...30M) Stromgren u-b 3500 - (4565+4785)/2 1.005 0.125 0.024 Stromgren b-y (4565+4785)/2 0.934 0.153 0.013 Stromgren v-y (4036+4167)/2 0.891 0.415 0.032 The color transformation for B-V was done using the airmass = 1 bandpass functions for B and V mag as given by Matthews & Sandage mag n_dv-y Bad v-y color comparision number=5 If indicated by a colon (:), this color comparison was not used in determining the color transformations. --- db-y 9.999? b-y color diff, US-SIMBAD number=4 The residuals from comparing the spectrophotometric colors with B-V, u-b, v-y, b-y colors from SIMBAD. The color transformations are as follows: Color Transformation Slope Z.P. error Johnson B-V Matthews & Sandage 1.072 0.433 0.021 (1963ApJ...138...30M) Stromgren u-b 3500 - (4565+4785)/2 1.005 0.125 0.024 Stromgren b-y (4565+4785)/2 0.934 0.153 0.013 Stromgren v-y (4036+4167)/2 0.891 0.415 0.032 The color transformation for B-V was done using the airmass = 1 bandpass functions for B and V mag as given by Matthews & Sandage mag n_db-y Bad b-y color comparision number=5 If indicated by a colon (:), this color comparison was not used in determining the color transformations. --- dkurbl 9.999? Kurucz comparison, blue col number=6 These are the average residuals from the best fit of Kurucz main sequence model spectral energy distributions to the main sequence stars in our sample. dkurbl are the residuals for the three colors with one passband falling below 4000 angstroms. dkurrd are the residuals for the 12 colors with both passbands falling at or above 4000 angstroms. Note that the residuals from the Kurucz fit (dkurbl and dkurrd) are well-correlated with the residuals from the uvby fits (dkurbl with du-b; dkurrd with db-y), so that the size of the color residuals is a good indication of the error of spectrophotometric observation, as detailed in the paper. mag dkurrd 9.999? Kurucz comparison, red col number=6 These are the average residuals from the best fit of Kurucz main sequence model spectral energy distributions to the main sequence stars in our sample. dkurbl are the residuals for the three colors with one passband falling below 4000 angstroms. dkurrd are the residuals for the 12 colors with both passbands falling at or above 4000 angstroms. Note that the residuals from the Kurucz fit (dkurbl and dkurrd) are well-correlated with the residuals from the uvby fits (dkurbl with du-b; dkurrd with db-y), so that the size of the color residuals is a good indication of the error of spectrophotometric observation, as detailed in the paper. mag Vabs Absolute V mag number=7 The absolute V magnitude, extinction corrected, according to the following values for reddening and distances: dist(pc) E(B-V) Praesepe 180 0.03 Hyades 43 0.00 Coma Berenices 90 0.00 M39 290 0.06 Pleiades 180 0.06 IC 4665 470 0.17 alpha Persei 230 0.10 The distances are estimated by a direct fit of the ZAMS line from Mihalas & Binney (1981, Galactic Astronomy (Freeman, New York) p. 106) to the V vs. B-V diagrams as published in our paper. The reddenings come from the 5th edition of the Lund-Strasbourg Catalog (Lynga 1987, Cat. <VII/92>) mag CDS 1998Feb05AAS CD-ROM series, Volume 9, 1997ASU] Oct-01-1997 J_AJ_114_699.xml