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J/AJ/135/1249       The early spectra of eta Carinae          (Humphreys+, 2008)

The early spectra of eta Carinae 1892 to 1941 and the onset of its high excitation emission spectrum. Humphreys R.M., Davidson K., Koppelman M. <Astron. J., 135, 1249-1263 (2008)> =2008AJ....135.1249H
ADC_Keywords: Stars, Be ; Spectroscopy ; Line Profiles Keywords: stars: emission-line, Be - stars: individual (η Car) - stars: winds, outflows Abstract: The observed behavior of η Car from 1860 to 1940 has not been considered in most recent accounts, nor has it been explained in any quantitative model. We have used modern digital processing techniques to examine Harvard objective-prism spectra made from 1892 to 1941. Relatively high excitation HeIλ4471 and [FeIII]4658 emission, conspicuous today, were weak and perhaps absent throughout those years. Feast et al. (2001MNRAS.322..741F) noted this qualitative fact for other pre-1920 spectra, but we quantify it and extend it to a time only three years before Gaviola (1953ApJ...118..234G)'s first observations of the high-excitation features. Evidently the supply of helium-ionizing photons (λ<504Å) grew rapidly between 1941 and 1944. The apparent scarcity of such far-UV radiation before 1944 is difficult to explain in models that employ a hot massive secondary star, because no feasible dense wind or obscuration by dust would have hidden the photoionization caused by the proposed companion during most of its orbital period. We also discuss the qualitative near-constancy of the spectrum from 1900 to 1940, and η Car's photometric and spectroscopic transition between 1940 and 1953. Description: Harvard objective prism plates : ------------------------------------------------------------------ Series Telescope Scale("/mm) Dates Location ------------------------------------------------------------------ A 24inch Bruce Doublet 60 1896-1926 Peru A 1929-1950 South Africa B 8inch Bache Doublet 179 1891-1923 Peru B 1930-1954 South Africa X 13inch Boyden Refractor 42.4 1891-1926 Peru X 1930-1951 South Africa ------------------------------------------------------------------ Objects: ------------------------------------------------- RA (2000) DE Designation(s) ------------------------------------------------- 10 45 03.6 -59 41 04 eta Carina = V* eta Car ------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file tablea1.dat 116 112 The Harvard objective prism plates of Eta Car orig_sp/* 0 33 Original scans of digitized spectra (fits) rect_sp/* 0 12 Examples of the rectified spectra of the scans (fits) tracings/* 0 22 Extracted 1D tracings with wavelength calibration for the spectra (pdf)
See also: J/ApJS/181/473 : Analysis of the spectrum of eta Car (Nielsen+, 2009) J/AJ/135/1249 : The early spectra of eta Carinae (Humphreys+, 2008) J/A+A/419/215 : Emission lines of eta Car (Hartman+, 2004) J/A+AS/133/299 : Long-term spectroscopy of eta Carinae (Damineli+ 1998) http://archive.stsci.edu/prepds/etacar/ : HST treasury program on eta Car http://etacar.umn.edu/ : eta car research group site Byte-by-byte Description of file: tablea1.dat
Bytes Format Units Label Explanations
1- 6 A6 --- Plate Plate number (A,B, or X + NNNNN) 8 A1 --- n_Plate [b] means "digitized" 10- 19 A10 "YYYY/MM/DD" Date Calendar date of observation 21- 27 I7 JD MJD Julian date of observation 29- 31 I3 min texp ?=- Exposure time 33- 36 F4.2 --- Phase Phase in the 5.5yr spectroscopic cycle 38- 77 A40 --- Comm ?=--- Comments about the spectrum 80 A1 --- n_Comm Note on spectral features (1) 82- 92 A11 --- OrigSp Original scan of digitized spectrum 94-105 A12 --- RectSp Example of the rectified spectrum of the scan 107-116 A10 --- Tracings Extracted 1D tracings with wavelength calibration for the spectrum
Note (1): Flags as follows: a = Weak absorption line spectrum; Hβ, Hγ, Hδ, [FeII]4359Å emission lines. c = Absorption lines barely discernible; Hβ, Hγ emission. d = Absorption lines very weak or gone; Hβ, Hγ, Hδ, [FeII]4359Å emission lines. e = Hydrogen, FeII, [FeII] emission.
History: From electronic version of the journal
(End) Emmanuelle Perret [CDS] 13-Jul-2010
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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