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II/43 K-Line Photometry of Southern A Stars, Table I (Henry+ 1971)
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K-Line Photometry of Southern A Stars, Table I:
Summary of Data on Southern A Stars
Henry R.C. and Hesser J.E.
<Astrophys. J. Suppl., 23, 421 (1971)>
=1971ApJS...23..421H
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ADC_Keywords: Photometry, K-line ; Stars, A-type
Description:
The photoelectric measurements of the strength of the Calcium K-line
has been extended by 223 stars of predominantly southern or equatorial
declinations which are well distributed in right ascension. This has
expanded the existent list to 369 field stars for which a k-index is
available, including many more Am stars. All available k-index data
for field stars are presented here.
Introduction:
The present work represents a continuation of that described previously
(Henry 1968ApJ...152L..87H, 1969ApJS...18...47H [hereinafter
referenced as Paper I]), in which the K-line of calcium at 3933{AA} is
measured photoelectrically in A-type stars with a narrow-band
spectrometer. The result for each star is a K-line-strength index,
called k, the value of which appears to depend predominantly only on
the temperature of the star and the abundance of calcium in its
atmosphere. The temperature dependence is well known; the abundance
dependence appears as a correlation between the residual dK in K
(after allowance for the temperature effect) and the difference from
normal of the general metallicity index [m1] of Stromgren (1966).
Alternatively, it was shown in Paper I that the calcium abundance is
probably the effective factor in producing the scatter in the relation
between k and b-y by a process of elimination of other parameters
(luminosity, etc.) that were found not to affect appreciably the value
of k. The value of k is, however, affected by a third parameter,
namely, whether the star is an Am star or not.
Many of the stars of Paper I were reobserved in order to tie in the
new measurements with the old ones. An emphasis was laid on observing
more Am stars, and on observing some stars that are of somewhat
earlier spectral types than the earliest ones observed previously.
Simultaneously with the field-star measurements described here,
extensive data were acquired for the A stars in five open clusters
(Hyades, Pleiades, IC 2391, IC 2602, and NGC 6475) and one association
(Orion), as described in Paper III (Hesser and Henry
1971ApJS...23..453H).
The observations were made with the same instrument that was used to
obtain the data for Paper I, and a description of the instrument may
be found in that paper.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
data.dat 111 369 Data from table 1
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Byte-by-byte Description of file: data.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- HR HR Number (Cat. <V/50>)
5- 9 F5.2 mag Vmag *Visual Magnitude from BSC.
11- 15 F5.2 mag B-V ? (B-V)-Color from BSC.
17- 21 F5.3 mag Knew ? New k-Index in Magnitude
23- 27 F5.3 mag e_Knew *? RMS-Error of New k-Index
28- 33 F6.3 mag K *Final Value of k-Index
35- 39 F5.3 mag e_K ? RMS-Error of final k-Index
40- 45 F6.3 mag dK *? Deviation of k-Index
47 A1 --- class *[LIE] Class of the Star
49- 54 F6.3 mag b-y *? (b-y)-Color from Stromgren-Perry Catalogue
55- 60 F6.3 mag E(b-y) *? Color excess
62- 66 F5.3 mag beta *? beta-Index
68- 72 F5.3 mag m1 ? Stromgren m1-Reddening-Independent-Index
73- 78 F6.3 mag dm1 *? Deviation of m1-Index
80- 84 F5.3 mag c1 ? Stromgren c1-Reddening-Independent-Index
86- 89 F4.2 mag dV *? Magnitudes Above the Main-Sequence
91- 95 F5.3 mag u-b ? (u-b)-Index of Stromgren
96-101 F6.3 mag a *? a-Index or dm1
102-107 F6.3 mag r ? r-Luminosity-Index of Stromgren; I-Stars
109-111 I3 --- ID record number
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Note on Vmag:
Hoffleit (1964, see Cat. <V/50>), but, where necessary, from Blanco et
al. (1968)
Note on e_Knew:
RMS error was not calculated if fewer than 4 observations were
available.
Note on K:
If fewer than 4 new observations were available, then present data
were combined with data from paper I.
Note on dK:
Deviation of k-index from the normal value for stars of the same
color. A positive dK has the sense of an over-abundance of calcium.
Note on class:
on the system of Stromgren (1966)
L = Late group star (later than A3)
I = Intermediate star (A0-A3)
E = Early star (B stars)
Note on b-y:
Stromgren & Perry (1965) and Crawford et al. (1970AJ.....75..624C)
Note on E(b-y):
Determined by the method of Stromgren. This value has been added to
observed (b-y) to obtain the b-y values given in this catalog.
Note on beta:
Crawford & Mander (1966AJ.....71..114C) and Crawford et al.
(1966AJ.....71..709C, 1970AJ.....75..624C)
Note on dm1:
Deviation of m1-index from the value for normal main-sequence stars. A
negative value indicates high metal abundances.
Note on dV:
The number of magnitudes the star has evolved above the main-sequence
calculated from data of c1-index.
Note on a:
For E-group stars this is d(m1) calculated by the alternate method
while for I-group stars it is the a-index temperature parameter of
Stromgren.
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References:
Blanco V.M., Demers S., Douglass G.G., and FitzGerald M.P. 1968, Pub. U.S.
Naval Obs., Vol. 21.
Crawford D.L. 1970, in Stellar Rotation, ed. A. Slettebak (Dordrecht:
D. Reidel Publishing Co.), p. 204.
Crawford D.L., Barnes J.V., Faure B.Q., Golson J.C., and Perry C.L. 1966,
A.J., 71, 709. (1966AJ.....71..709C)
Crawford D.L., Barnes J.V. and Golson J.C. 1970, A.J., 75, 624.
(1970AJ.....75..624C)
Crawford D.L. and Mander J. 1966, A.J., 71, 114. (1966AJ.....71..114C)
Henry R.C. 1968, Ap. J. (Letters), 152, L87. (1968ApJ...152L..87H)
Henry R.C. 1969, Ap. J. Suppl., 18, 47 (1969ApJS...18...47H) (Paper I).
Hesser J.E. and Henry R.C. 1971 Ap. J. Suppl., 23, 453 (Paper III).
(1971ApJS...23..453H)
Hoffleit D. 1964, Catalog of Bright Stars (New Haven: Yale University Obs.).
(See Cat. <V/50>)
Stromgren B. 1963, Quart. J. Roy. Astron. Soc., 4, 8.
Stromgren B. 1966, Ann. Rev. A&A, 4, 433.
Stromgren B. 1967, in The Magnetic and Related Stars, ed. R. C.
Cameron (Baltimore: Mono Book Corp.), p. 461.
Stromgren B., and Perry C.L. 1965, unpublished.
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(End) Julie Anne Watko [SSDOO/ADC] 10-Apr-1996