II/43 K-line photometry of Southern A stars (Henry+ 1971)
K-line photometry of Southern A stars, Table I:
Summary of data on Southern A stars
Henry R.C. Hesser J.E.
<Astrophys. J. Suppl., 23, 421 (1971)>
=1971ApJS...23..421H 1971ApJS...23..421H
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 1968ApJ...152L..87H, 1969ApJS...18...47H 1969ApJS...18...47H = II/42,
[hereinafter referenced as Paper I]), in which the K-line of calcium
at 3933Å 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. 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 & Henry 1971ApJS...23..453H 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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See also:
II/42 : K-Line photometry of A stars (Henry, 1969)
II/44 : K-line photometry of stars in open clusters (Hesser+ 1971)
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 (Bright Star Catalog, Cat. V/50)
5- 9 F5.2 mag Vmag Visual Magnitude from HR (V/50) or Blanco (II/4)
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 knew (1)
28- 33 F6.3 mag k Final Value of k-Index (2)
35- 39 F5.3 mag e_k ? RMS-Error of final k-Index
40- 45 F6.3 mag dk ? Deviation of k-Index (3)
47 A1 --- Sg [LIE] Stroemgren's group (4)
49- 54 F6.3 mag b-y ? (b-y)-Color from Stromgren-Perry Catalogue (5)
55- 60 F6.3 mag E(b-y) ? Color excess (5)
62- 66 F5.3 mag beta ? Stromegren β-index (6)
68- 72 F5.3 mag m1 ? Stromgren [m1] reddening-insensitive index
73- 78 F6.3 mag dm1 ? Deviation δ[m1] of [m1] index (7)
80- 84 F5.3 mag c1 ? Stromgren [c1] reddening-insensitive index
86- 89 F4.2 mag dV ? Magnitudes above the main-sequence (8)
91- 95 F5.3 mag u-b ? (u-b)-Index of Stromgren
96-101 F6.3 mag a ? a-index or dm1 (9)
102-107 F6.3 mag r ? r Luminosity-index of Stromgren (10)
109-111 I3 --- ID [1/369] record number
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Note (1): RMS error was not calculated if fewer than 4 observations were
available.
Note (2): if fewer than 4 new observations were available, then present
data were combined with data from paper I (Cat. II/42)
Note (3): 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 (4): groups are:
L = Late group star (later than A3)
I = Intermediate group (A0-A3, i.e. early A)
E = Early group (B stars)
Note (5): from Stromgren & Perry (1965, unpublished) and Crawford et al.
(1970AJ.....75..624C 1970AJ.....75..624C); stars lacking uvby photometry but having
measured B-V have converted values. When the reddening E(b-y) is
known, the color index (b-y) is de-reddened.
Note (6): from Crawford & Mander (1966AJ.....71..114C 1966AJ.....71..114C) and Crawford et al.
(1966AJ.....71..709C 1966AJ.....71..709C, 1970AJ.....75..624C 1970AJ.....75..624C)
Note (7): deviation of [m1]-index from the value for normal main-sequence
stars. A negative value indicates high metal abundances.
Note (8): number of magnitudes the star has evolved above the main-sequence
calculated from data of [c1]-index.
Note (9): temperature index:
* for stars of the early-group (E), the value is δ[m1],
calculated by the alternate method
* for stars of the intermediate group (early A stars), it is defined as:
a = (b-y) + 0.189[(u-b) - 1.36mag]
Note (10): index which is ∼0 for zero-age star, defined as:
r = (β-2.565mag) - 0.35[c1]
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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 1966AJ.....71..709C)
Crawford D.L., Barnes J.V. and Golson J.C. 1970, A.J., 75, 624.
(1970AJ.....75..624C 1970AJ.....75..624C)
Crawford D.L. and Mander J. 1966, A.J., 71, 114. (1966AJ.....71..114C 1966AJ.....71..114C)
Henry R.C. 1968, Ap. J. (Letters), 152, L87. (1968ApJ...152L..87H 1968ApJ...152L..87H)
Henry R.C. 1969, Ap. J. Suppl., 18, 47 (1969ApJS...18...47H 1969ApJS...18...47H) (Paper I).
Hesser J.E. and Henry R.C. 1971 Ap. J. Suppl., 23, 453 (Paper III).
(1971ApJS...23..453H 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.
(End) Julie Anne Watko [SSDOO/ADC], rev. Francois Ochsenbein [CDS] 10-Apr-1996