II/24 H-α Photometry of Northern Late-Type Stars I. (Peat 1964)
H-α Photometry of Late-Type Stars. I.
F-, G- and K-Type Stars North of the Equator
Peat D.W.
<Mon. Not. R. Astron. Soc., 128, 435 (1964)>
=1964MNRAS.128..435P 1964MNRAS.128..435P
ADC_Keywords: Photometry, H-alpha; Stars, late-type; Stars, dwarfs
Description:
Observations are presented of the strength of the H-α absorption
line in the spectra of approximately 600 northern F, G and K stars of
differing luminosities and chemical compositions. Most of the stars in
this catalogue were previously observed by Griffin and Redman
(1960MNRAS.120..287G 1960MNRAS.120..287G), Deeming (1960MNRAS.121...52D 1960MNRAS.121...52D), and Griffin
(1961MNRAS.122..181G 1961MNRAS.122..181G). Data given in this catalog include HD number,
MK spectral classification, high velocity, (B-V) color index,
magnesium b ratio, sodium D line ratio and H-α ratio.
Introduction: (Peat, 1964)
The integrated light-intensity within a band defined by the wavelength
limits 6545-6580A, centered on the wavelength of H-α, was
measured by one photomultiplier. The combined integrated light
intensity within the two comparison regions defined respectively by
the wavelength limits 6477.5 to 6495.0A and 6630.0 to 6647.5A was
measured by a second photomultiplier. The wavelengths were monitored
using the bright neon emission at lambda 6402 produced by a neon
discharge tube, and were held constant to within ±0.5A. Errors of the
order of ± 2A in the wavelength setting, however, were found
experimentally to have no effect on the results, and corrections for
the Doppler shift due to the stellar radial velocity were therefore
unnecessary.
The "H-α ratio" R, was defined by the expression R =
[B/B(L)]/[A/A(L)] where B, A represent the photomultiplier output
counts for a star, in the side bands and H-α band respectively,
and B(L), A(L) represent the corresponding counts for the lamp. One
might expect this ratio to be partially determined by features, other
than H-α, situated within the central and comparison regions of
the stellar spectrum, but examination of a high resolution spectrogram
of Arcturus (a K2 giant star typical of the stars on the observing
program) taken by Griffin (1962) showed that these other features
affected the H-α ratio by less than 0.3%. This is only of the
same order as the estimated observational error in the H-α
ratios, and we shall assume therefore that the H-α ratio is
determined solely by the strength of the H-α absorption line.
Griffin (1961MNRAS.122..181G 1961MNRAS.122..181G) describes the three-channel
spectrophotometer with which observations were made at the coude focus
of the Cambridge Observatory 36 in reflecting telescope. Griffin and
Redman (1960MNRAS.120..287G 1960MNRAS.120..287G), Deeming (1960MNRAS.121...52D 1960MNRAS.121...52D), and
Griffin (1961MNRAS.122..181G 1961MNRAS.122..181G) describe the method of Observation and
reduction.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
data.dat 76 594 Photometric Results
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See also:
II/22 : HRA Photometry of Late-Type stars II. (Peat 1966)
II/63 : Balmer Lines Photometric Data (Mermilliod+ 1980)
Byte-by-byte Description of file: data.dat
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Bytes Format Units Label Explanations
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1-2 A2 --- --- [HD]
4-9 I6 --- HD HD (Cat. III/135) number of the star
16-19 A4 --- SpType Spectral classification
22-23 I2 --- lum [10/50]? Luminosity class indication (1)
28-29 A2 --- HV [ HVP] High Velocity (2)
43-46 F4.2 mag B-V ? (B-V) color index (3)
49-52 F4.2 --- Mgb ? Mg b ratio from Deeming (1960MNRAS.121...52D 1960MNRAS.121...52D)
55-59 F5.3 --- NaD ? Sodium D line ratioA from Griffin
(1961MNRAS.122..181G 1961MNRAS.122..181G)
61-65 F5.3 --- Ha [0.96/1.2] Hα ratio (Rα) (4)
74-76 I3 --- ID [1/594]+ Star number
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Note (1): Luminosity class coded as:
10: Ia 13: Iab 14: Iab-Ib 15: Ib
17: Ib-II 20: II 25: II-III 30: III
35: III-IV 40: IV 45: IV-V 50: V
Note (2):
'HV' indicates that the star is a high velocity star with a space motion
in excess of 63 km/s as determined by Eggen (1962RGOB...51...79E 1962RGOB...51...79E).
Note (3):
from Deeming (1960MNRAS.121...52D 1960MNRAS.121...52D) and Argue (1962MNRAS.125..557A 1962MNRAS.125..557A)
Note (4): the Hα ratio is computed as the ratio of the intensities
of comparison regions to Hα, the intensities being relative
to the calibration lamps:
comparison region A = 6469.0-6505.0Å
Hα (region B) = 6546.5-6582.5Å
comparison region C = 6624.0-6660.0Å
Rα = 0.5 (A/AL + C/CL)/(B/BL)
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References:
Argue A.N., 1962, Mon. Not. R. Astron. Soc., 125, 557. (1962MNRAS.125..557A 1962MNRAS.125..557A)
Deeming T.J., 1960, Mon. Not. R. Astron. Soc., 121, 52. (1960MNRAS.121...52D 1960MNRAS.121...52D)
Eggen O.J., 1962, Roy. Obs. Bull., 51. (1962RGOB...51...79E 1962RGOB...51...79E)
Griffin R.F., 1961, Mon. Not. R. Astron. Soc., 122, 181. (1961MNRAS.122..181G 1961MNRAS.122..181G)
Griffin R.F., 1962, private communication.
Griffin R.F. & Redman R.O., 1959, Mon. Not. R. Astron. Soc., 120, 287.
(1960MNRAS.120..287G 1960MNRAS.120..287G)
Peat D.W., 1964, Mon. Not. R. Astron. Soc., 128, 435 (1964MNRAS.128..435P 1964MNRAS.128..435P)
(End) Julie Anne Watko [SSDOO/ADC] May-1996, rev. F.Ochsenbein [CDS] 01-Jan-2000