MICHIGAN: Two-dimensional spectral types for HD stars(IV)

Table name:     Michigan
Records:        33301                                                          
Spectral Band:  OPT,Photo                                                     
Kind of Object: HD-Star                                                      
Mode:           Spectroscopy,Objective-Prism 
PreView:     
Coordinates:    J2000

Reference

Michigan Catalogue of Two Dimensional Spectral Types for the HD, Vol.4, Ann Arbor, Dept. of Astronomy, Univ. of Michigan

Description

This catalogue is part of a program of systematic reclassification of the Henry Draper stars on the MK system and contains all HD stars between dec = -26.0 and -12.0 degrees. The stars were classified visualy on objective-prism plates taken with the Michigan Curtis Schmidt telescope at Cerro Tololo Inter-American Observatory. The 4 + 6 degrees prisms yield a dispersion at Hgamma of 108 Angstrom/mm, and the resolution is about 2 Angstrom/mm, comparable to that of the original MK system. The spectra were taken on IIaO plates and widened to 0.8 mm, with 20 min, 4min, 1min exposures being obtained. The high quality of the spectra is illustrated in 'An Atlas of Objective-Prism Spectra' by N.Houk, N.J. Irvine and D. Rosenbush and 'A Second Atlas of Objective-Prism Spectra' by Nancy Houk and Michael V. Newberry. In order to mantain a uniform, consistent system, all the spectra classification was done by one person(NH). Over 170 standard stars were used. Of the 33301 stars in the catalogue, 32563 (98%) were classifiable. Internal classification errors were obtained using the stars classified independently on more than one plate. Both internal and external errors are similar to those usually obtained in the classification of slit spectra. 15% of the stars have remarks giving futher information. (See also the R_MICHIGAN catalogue.)

Fields

Name           Meaning                                                    

HD             HD number                                                  
pmag           Photographic magnitude                                     
pecul          Flag about peculiarity                                     
sp             Spectral type                                              
others         + means that the sp is taken from another source           
qur            Quality and Remarks code                                   
               Quality: 1 (best) to 4 (worst)                             
               Remarks code: B,L,O,R,D                                    
var            V means that the star is variable                          
remark         Remark from the r_michigan catalogue                       
ra_ori         Right ascension: epoch 1900.0                              
dec_ori        Declination:     epoch 1900.0                              
lii_ori        Galactic longitude (integer 2 bytes)                       
bii_ori        Galactic latitude (integer 2 bytes)                        
ra             Right ascension: epoch 2000.0                              
dec            Declination:     epoch 2000.0                              
lii            Galactic longitude (integer 4 bytes)                       
bii            Galactic latitude (integer 4 bytes)                        
prc_ra         100 years Precession in (alp)                              
prc_dec        100 years Precession in (del)                              
DM             DM number                                                  
SAO            SAO number                                                 
plate          Plate codes

REMARKS

Further information about 5144 stars is given in the 'remark' field (taken from the r_michigan catalogue). The kind of information that one can find in this field is indicated in the 'qur' field:

B Indicates that the remark contains the HR (Bright Star Catalogue) number and the Bayer or Flamsteed designations where applicable (1154 stars).
L Indicates that information from the astronomical literature is given. Remarks were generally restricted to those relevant to the spectral appearance, such as rotation, variability, and duplicity, and generally have included only information about the star which might affect the spectral classification.
The entry "emission catalogue" refers to Wackerling's catalogue.
O Includes 355 remarks that do not fit into any other catalogue. Almost all of these are NGC or IC designations for nebulae or identification numbers from the CoD, SD, etc.
R 1147 of the stars in the remarks section have remarks of this type. All 'R' remarks were written by NH in the course of the spectral classification and are all related in some way to the spectrum.
D The Stellar Data Center at Strasbourg provided a listing of visual double stars. Remarks beginning "undetected visual double" were included for doubles not discovered in the course of the spectral classification, the others having 'R' remarks.
D remarks were included for the 1932 doubles having a separation = 30 arcsec and a (DEL)mag > 4.0 mag, since for these the spectral appearance and hence the assigned spectral type might be affected. Spectra classified as weak metal, Am, or Ap were re-examined by Houk to be sure these characteristics were not due to the double.

MICHIGAN: Two-dimensional spectral types for HD stars(IV)

Contents

Reference

Description

Fields

REMARKS