The Astrophysical Journal Supplement Series, 180:117–118, 2009 January c 2009. The American Astronomical Society. All rights reserved. Printed in the U.S.A.
doi:10.1088/0004-6256/180/1/117
MK CLASSIFICATIONS OF SPECTROSCOPIC BINARIES Helmut A. Abt Kitt Peak National Observatory, Box 26732, Tucson, AZ 85726-6732, USA;
[email protected] Received 2008 July 22; accepted 2008 September 12; published 2008 December 23
ABSTRACT New MK spectral classifications are given for 145 spectroscopic binaries (SBs) with AF primaries because twodimensional types are lacking for more than one-third of the AF SBs with known orbital elements in the current catalog. Compared with the classifications by Morgan, Keenan, and their students, the new classifications give types that are 1.1 ± 0.2 subclasses later and 0.7 ± 0.1 luminosity classes fainter. Also listed are selected published MK types from Brian Skiff’s recent compilation. Key words: binaries: spectroscopic – stars: fundamental parameters Online-only material: machine-readable table
1. INTRODUCTION
spectra were 1.2 mm wide. They were classified against MK standards on a Boller & Chivens spectra comparator. Table 1 is available in full only online; in the printed edition there is only a sample. Column (1) gives the running number in SB8 and SB9; they differ from the numbers in SB7. Some stars observed in SB7 were later deleted from the catalogs, so they have no SB8/9 numbers in Table 1. Column (2) gives the Henry Draper (HD) number (if the stars have them) and Column (3) gives other designations, e.g., the Aitken (1932) double star (ADS) components observed and variable stars’ designations. If a star has both a Bright Star Catalogue (Hoffleit and Jaschek 1982) number (HR) and constellation name, the latter is not always given. Column (4) tells whether the star is a single-lined (SB1) or double-lined (SB2) system. For SB2s there may be two types given in the following columns if their spectra show obvious composite spectra; otherwise the types are blends of the two. Column (5) gives the new classifications. Compared with the classifications for 83 stars by Morgan, Keenan, and their students (see the list below), the new types are 1.1 ± 0.2 (standard error per star) subclasses later and 0.7 ± 0.1 luminosity classes fainter. These errors agree well with previous estimates with such spectra, namely 0.1 ± 1.1 subclasses earlier and 0.2 ± 0.8 classes fainter (Abt 1985). The published comparison classifications in Column (6) were obtained mostly from the many published choices offered by Skiff. In selecting one for each star, we gave preference to classifications by Morgan and Keenan, their students (Abt, Bidelman, Cowley, Garrison, Roman, and Slettebak), and their students’ student (Gray). The new classifications given in this paper and the other published classifications listed by Skiff will be used in planned further statistical studies of spectroscopic binaries characteristics. I thank the second referee for suggesting many minor corrections.
The recent catalogs of the orbital elements of spectroscopic binary (SB) systems (SB7, SB8, SB9) are exhaustive compilations of the published data on SB orbital elements. The authors used excellent judgment of the orbital data and their references are included. The seventh catalog (SB7) by Batten et al. (1978) and eighth catalog by Batten et al. (1989) were printed; the ninth catalog (SB9) is available online only (Pourbaix et al. 2004; http://sb9.astro.ulb.ac.be). However, some of the auxiliary information, such as spectral types, may be lacking in those catalogs. For instance, more than one-third of the AF spectral types in the current version of SB9 are not MK or two-dimensional types. This project is an attempt to partially correct that omission. In 1985 and 1986, I obtained spectra for classification of the A- and F-type northern (> −30◦ declination) binaries in SB7 that had no MK types or recent classifications. The new classifications for 145 binaries are given in Table 1. In addition, Brian Skiff’s recent compilation makes available many new published MK types. His compilation can be accessed in the Web address: Strasbourg Astronomical Data Center (CDS), VizieR, and B/mk. We are all indebted to Brian for bringing nearly up to date a compilation (with references) of published MK spectral types. For statistical analyses of SBs, we often need good spectral types. Therefore I present these new types. Readers may decide whether to use these new ones or the previously published ones now listed in Brian Skiff’s compilation. My only reservation with my current ones is that with the dispersion used here (128 Å mm−1 ) I was unable to identify some Ap(HgMn) stars such as HD 358. 2. THE DATA The photographic spectra were obtained with the Meinel Cassegrain spectrograph on the Kitt Peak 0.9 m telescope. The resolution on the Kodal IIa-O plates was 15 μ = 1.9 Å and the
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Table 1 MK Spectral Classifications of SB9 Stars SB8/9 (1)
HD (2)
Other Designations (3)
Kind (4)
New Classification (5)
Published Classification (6)
4
358
HR 15 ADS 94A
SB1
B9 II
B9p(HgMn) (Morgan et al. 1943)
9 16 27
861 1826 3196
SB1 SB1 SB1
Am(K/H/M = A2/A2/A4) A5 V F8 V
Am (Slettebak & Nassau 1959) Am (Bidelman 1988) F8 V (Roman 1952)
46 ...
4676 5015
SB2 ...
F8 V F9 V
F8 V (Roman 1952) F8 V (Slettebak 1955)
74
8556
SB1
F4 V
F3 V (Abt 1981)
75 77
8634 9021
SB1 SB1
F6 V F6 V
F6 IV (Cowley 1976) F6 V (Cowley 1976)
...
9826
...
F9 V
F8 V (Johnson & Morgan 1953)
LR And HR 142 ADS 490AB 13 BU Cet HR 225 HR 244 ADS 721A HR 404 ADS 1123AB HR 407 HR 427 38 Cas HR 458 IDS 01310+4054
(This table is available in its entirety in machine-readable form in the online journal. A portion is shown here for guidance regarding its form and content.)
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