J/A+AS/109/313ivo://CDS.VizieR/J/A+AS/109/313CDSRoberts W.J.Grebel E.K.2003-02-14T16:02:45Z2003-02-14T17:02:31ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frextinctionstellar-atmospheresIn synthetic versions of two broadband photometric systems, Johnson-Cousins and Washington, we find the dependence of atmospheric extinction corrections on colour and on macro features in the spectra of stars, such as the Balmer jump, as parameterised by Teff, logg, and [Fe/H]. We use standard passbands, a mean atmospheric extinction law measured at ESO/La Silla, extended and modified by us, and the Kurucz library of synthetic spectra. The true broadband atmospheric extinction is far more complicated than any current reduction (transformation) methods consider. Hence all broadband magnitude systems are fundamentally unphysical - they contain not the extra-atmospheric magnitudes, but unobservable magnitudes whose relation to physical magnitudes is unknown, but may differ by 0.05mag or more for hot and cool stars. Hence, it is hazardous to compare them to any synthetic magnitude system derived from either synthetic spectra or spectral scans. These problems exist to a lesser degree in intermediate band systems, but narrow band systems are relatively immune from these complexities. We do not treat either kind of system here. If our results were incorporated into a photometric reduction program, and standard stars and program stars stars carefully selected by metallicity and luminosity class, a standard magnitude system could be established that would be directly comparable to synthetic systems. As a bonus, measurements of intrinsic flux variations at the millimagnitude level would become more secure. We describe our own operational photometric transformation program that incorporates only the linear part of the dependence on colour of atmospheric extinction. Our results and prescriptions are useful for aperture photoelectric photometry, but our implementation is aimed at CCD photometry of stellar populations.1995A&AS..109..313Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+AS/109/313CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+AS/109/313https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+AS/109/313http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+AS/109/313https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+AS/109/313https://vizier.iucaa.in/viz-bin/votable?-source=J/A+AS/109/313http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+AS/109/313GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+AS/109/313/coeff2*Actual coefficientsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBandQuantity, e.g., filter or colourmeta.code;instr.filtercharlogg[]? Surface gravitylog(cm.s**-2)phys.gravityfloatnullablen_logg[m ] Lowest surface gravity model when there is no value for logg (1)meta.notechar[Fe/H]Metallicitylog(Sun)phys.abund.Fefloata0Coefficient a0 in the numeratorstat.fit.paramdoublea1Coefficient a1 in the numeratorstat.fit.paramdoublea2[]? Coefficient a2 in the numeratorstat.fit.paramdoublenullablea3[]? Coefficient a3 in the numeratorstat.fit.paramdoublenullablea4[]? Coefficient a4 in the numeratorstat.fit.paramdoublenullablea5[]? Coefficient a5 in the numeratorstat.fit.paramdoublenullablea6[]? Coefficient a6 in the numeratorstat.fit.paramdoublenullablea7[]? Coefficient a7 in the numeratorstat.fit.paramdoublenullableb1[]? Coefficient b1 in the denominatorstat.fit.paramdoublenullableb2[]? Coefficient b2 in the denominatorstat.fit.paramdoublenullableb3[]? Coefficient b3 in the denominatorstat.fit.paramdoublenullableb4[]? Coefficient b4 in the denominatorstat.fit.paramdoublenullableb5[]? Coefficient b5 in the denominatorstat.fit.paramdoublenullableb6[]? Coefficient b6 in the denominatorstat.fit.paramdoublenullableJ/A+AS/109/313/diffbDifferential atmospheric extinction in UBVRIrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarStar type (G1)src.classchar[Fe/H]Metallicitylog(Sun)phys.abund.FefloatTeffeffective temperatureKphys.temperature.effectivefloatU-B(U-B) colour indexmagphot.color;em.opt.U;em.opt.BfloatK(U-B)Differential atmospheric extinction coefficient in (U-B)obs.atmos.extinctionfloatR1K(U-B)/K(B-V) ratiophys.absorptionfloatB-V(B-V) colour indexmagphot.color;em.opt.B;em.opt.VfloatK(B-V)Differential atmospheric extinction coefficient in (B-V)obs.atmos.extinctionfloatR2K(B-V)/K(B-V) ratiophys.absorptionfloatV-R(V-R) colour indexmagphot.color;em.opt.V;em.opt.RfloatK(V-R)Differential atmospheric extinction coefficient in (V-R)obs.atmos.extinctionfloatR3K(V-R)/K(B-V) ratiophys.absorptionfloatR-I(R-I) colour indexmagphot.color;em.opt.R;em.opt.IfloatK(R-I)Differential atmospheric extinction coefficient in (R-I)obs.atmos.extinctionfloatR4K(R-I)/K(B-V) ratiophys.absorptionfloatV-I(V-I) colour indexmagphot.color;em.opt.V;em.opt.IfloatK(V-I)Differential atmospheric extinction coefficient in (V-I)obs.atmos.extinctionfloatR5K(V-I)/K(B-V) ratiophys.absorptionfloatJ/A+AS/109/313/coeff1*Rational polynomial coefficientsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFilterFilters or quantity involved (1)meta.code;instr.filtercharBandQuantity, e.g., filter or colourmeta.code;instr.filtercharlogg[]? Surface gravitylog(cm.s**-2)phys.gravityfloatnullablen_logg[m ] Lowest surface gravity model when there is no value for logg (2)meta.notechar[Fe/H]Metallicitylog(Sun)phys.abund.FefloatnumNumerator degree (3)stat.fit.paramintdenDenominator degree (3)stat.fit.paramintMaxDevLargest deviation (4)stat.fit.paramdoubleTCminLower boundary of the valid range of temperature colour for that fit (5)stat.fit.paramfloatTCmaxUpper boundary of the valid range of temperature colour for that fit (5)stat.fit.paramfloatJ/A+AS/109/313/diffwDifferential atmospheric extinction in CMT1T2StarStar type (G1)src.classcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[Fe/H]Metallicitylog(Sun)phys.abund.FefloatTeffeffective temperatureKphys.temperature.effectivefloatC-M(C-M) colour indexmagphot.colorfloatK(C-M)Differential atmospheric extinction coefficient for (C-M)obs.atmos.extinctionfloatR1K(C-M)/K(M-T2) ratiophys.absorptionfloatM-T1(M-T1) colour indexmagphot.colorfloatK(M-T1)Differential atmospheric extinction coefficient for (M-T1)obs.atmos.extinctionfloatR2K(M-T1)/K(M-T2) ratiophys.absorptionfloatT1-T2(T1-T2) colour indexmagphot.colorfloatK(T1-T2)Differential atmospheric extinction coefficient for (T1-T2)obs.atmos.extinctionfloatR3K(T1-T2)/K(M-T2) ratiophys.absorptionfloatM-T2(M-T2) colour indexmagphot.colorfloatK(M-T2)Differential atmospheric extinction coefficient for (M-T2)obs.atmos.extinctionfloatR4K(M-T2)/K(M-T2) ratiophys.absorptionfloatM-51(M-DDO51) colour indexmagphot.colorfloatK(M-51)Differential atmospheric extinction coefficient for (M-DDO51)obs.atmos.extinctionfloatR5K(M-51)/K(M-T2) ratiophys.absorptionfloatJ/A+AS/109/313/totbTotal atmospheric extinction in UBVRIrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarStar type (G1)src.classchar[Fe/H]Metallicitylog(Sun)phys.abund.FefloatTeffEffective temperatureKphys.temperature.effectivefloatK(U)XTotal atmospheric extinction coefficient in U for airmass 1 (because U filter is defined by atmospheric cutoff, see paper II)magobs.atmos.extinctiondoubleK(B)XTotal atmospheric extinction coefficient in B for airmass 1 (to allow calculation of U-B.)magobs.atmos.extinctiondoubleK(B)Total atmospheric extinction coefficient in B for airmass 0magobs.atmos.extinctiondoubleK(V)Total atmospheric extinction coefficient in V for airmass 0magobs.atmos.extinctiondoubleK(R)Total atmospheric extinction coefficient in R for airmass 0magobs.atmos.extinctiondoubleK(I)Total atmospheric extinction coefficient in I for airmass 0magobs.atmos.extinctiondoubleJ/A+AS/109/313/totwTotal atmospheric extinction in CMT1T2recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarStar type (G1)src.classchar[Fe/H]Metallicitylog(Sun)phys.abund.FefloatTeffEffective temperatureKphys.temperature.effectivefloatKCTotal atm. ext. for C Washington bandobs.atmos.extinctiondoubleKMTotal atm. ext. for M Washington bandobs.atmos.extinctiondoubleKT1Total atm. ext. for T1 Washington bandobs.atmos.extinctiondoubleKT2Total atm. ext. for T2 Washington bandobs.atmos.extinctiondoubleK51Total atm. ext. for DDO 51 Washington bandobs.atmos.extinctiondouble