The UBViyz photometric system

Basic Reference

Jennens P.A., Helfer H.L. 1975, Mon. Not. R. Astr. Soc. 172, 667

Abstract

Photometry of 260 G and K giants, using a fast broad-intermediate band photometric system (UBViyz system) is used to calibrate chemical composition, [Fe/H], luminosity, Mv and colour excess, E(B-V). A simple S-20 surface photomultiplier is used. The UBVi photometry is transformed to be on the Johnson UBVRI system.

Calibrations applicable to the ranges 0.40 < R-I < 0.65 (G2-K3), 0.65 < R-I < 0.90 (K3-K5) are given. A photometric luminosity index, Mv(yz), is derived for which rms errors are +- 1 mag. Several indices are calibrated for chemical composition, [Fe/H], and typical rms errors of +- 0.15 in [Fe/H] are obtained for stars of known colour excess, E(B-V). For stars of unknown colour excess, E(B-V) is determined with an rms error of +- 0.06 and [Fe/H] with an rms error of ~+- 0.4. For stars with Mv < -1, the errors are larger.

Content

Access to the data and references

Asiago Database on Photometric System (ADPS)

Indices and Parameters

V, U-B, B-V, Y-V, Y-Z, V-i

Filters

U : Corning 9863 + CuSO4
Lam_eff : 3660 Å ; Width : 600 Å
B : Corning 5030 + 1 mm Schott 9913 + CuSO4
Lam_eff : 4400 Å ; Width : 900 Å
V : Corning 3384 + 1.6 mm Schott BG18
Lam_eff : 4930 Å ; Width : 700 Å
i : 3 mm D RG 780
Lam_eff : 7900 Å ; Width : 600 Å
y : Baird Atomic 12-39-5
Lam_eff : 4600 Å ; Width : 200 Å
z : Baird Atomic 14-74-4
Lam_eff : 5160 Å ; Width : 200 Å

Photomultiplier


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Jean-Claude.Mermilliod@obs.unige.ch
Last update: 13 September 2002