II/168 Homogeneous Means in the UBV System (Mermilliod 1991)
Catalogue of Homogeneous Means in the UBV System
Mermilliod J.C.
<Institut d'Astronomie, Universite de Lausanne (1991)>
ADC_Keywords: Photometry, UBV
Description:
The present catalog supersedes an earlier edition of Nicolet (1978).
It is a collection of weighted mean photoelectric values (V, B-V, U-B)
for stars measured in the UBV system. The mean values were computed by
combining all individual measurements compiled in the catalog of
Mermilliod (1987), except those that were clearly found to be
erroneous for some reason or another. Some newer observations compiled
since 1987 are also included in the means. The procedure for computing
the homogeneous means involved the calculation of normal averages
weighted by the number of observations in each list (unity when not
published). New weights are assigned based on the deviation of each
value from the previous mean, then a new weighted mean is computed.
This technique is not as rigorous as that used by Nicolet (comparison
of each list with the standard system master list), but the latter
cannot often be realized effectively in practice, since many lists do
not contain enough stars in common with a standard list. Also, there
are now so many references (more than 1500) that it is not feasible to
analyze each publication with respect to a standard list. This edition
of the catalog contains 92964 stars measured since the introduction of
the UBV system in 1953. The data included are star identification in
the Geneva coded numbering system, double and variable codes, UBV data
and their standard deviations, and number of observations. A second
file contains the definition of the coded numbering system.
The catalog was prepared at the Institut d'Astronomie de l'Universite
de Lausanne in Geneva.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
ubvmeans.dat 72 92964 Catalog Data
doc.txt 72 100 Author's documentation
coding.txt 80 2630 Numbering system documentation
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Byte-by-byte Description of file: ubvmeans.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- LID Lausanne identification number (1)
11 A1 --- m_LID Lausanne component (D, 1, 2, ...) (1)
12 A1 --- var [V] Variability code.
14- 15 I2 --- Npub Number of publications (separate lists)
contributing observations to the means
17- 22 F6.3 mag Vmag ?Mean V magnitude (Precision varies)
25- 29 F5.3 mag e_Vmag ?Standard deviation for Vmag
31 A1 --- n_Vmag [>S/] Standard (S) or note on o_Vmag (2)
32- 34 I3 --- o_Vmag ?Number of observations for Vmag
36- 41 F6.3 mag B-V ?Mean (B-V) color index (Precision varies)
44- 48 F5.3 mag e_B-V ?Standard deviation for B-V
50 A1 --- n_B-V [>S/] Standard (S) or note on o_B-V (2)
51- 53 I3 --- o_B-V ?Number of observations for B-V
55- 60 F6.3 mag U-B ?Mean (U-B) color index (Precision varies)
63- 67 F5.3 mag e_U-B ?Standard deviation for U-B
69 A1 --- n_U-B [>S/] Standard (S) or note on o_Vmag (2)
70- 72 I3 --- o_U-B ?Number of observations for U-B
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Note (1):
The Lausanne identification number is comprised of both the LID and
m_LID fields, detailed in the "coding.txt" file. The "D" in the m_LID
field indicates that more than one component of a multiple system was
included in the diaphragm when the observation was made.
Note (2):
S indicates standard star
> indicates a minimal number of observations
/ indicates number of observations is unknown
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History:
* 07-Dec-1992: File received at CDS from J.-C. Mermilliod (Lausanne)
* 05-Sep-1997: Standardisation by James E. Gass [SSDOO/ADC]
* 07-May-2006: Rewriting of the codes for standard stars (F. Ochsenbein, CDS)
References:
Mermilliod, J.-C., & Mermilliod, M.: 1994, "Catalog of mean UBV
data on stars." Springer-Verlag, New York
Mermilliod, J.-C. 1978BICDS..14...32M 1978BICDS..14...32M, Cat. II/58
Mermilliod, J.-C. 1987a (1987A&AS...71..119M 1987A&AS...71..119M), Cat. II/122
Mermilliod, J.-C. 1987b (1987A&AS...71..413M 1987A&AS...71..413M), Cat. II/122
Mermilliod, J.-C. 1987c (1987BICDS..32...37M 1987BICDS..32...37M), Cat. II/122
Mermilliod, J.-C., & Nicolet, B. 1977A&AS...29..259M 1977A&AS...29..259M, Cat. II/35
Nicolet, B. 1978, 1978A&AS...34....1N 1978A&AS...34....1N, Cat. II/51
Nicolet, B., & Hauck, B. 1977, in Compilation, Critical Evaluation and
Distribution of Stellar Data, ed. C. Jaschek & G. A. Wilkins
(Dordrecht, Reidel), p. 121
(End) James E. Gass [SSDOO/ADC], Francois Ochsenbein [CDS] 07-May-2006