J/AJ/101/1408 Massive stars in Cyg OB2. (Massey+ 1991)
Massive stars in Cyg OB2.
Massey P., Thompson A.B.
<Astron. J. 101, 1408 (1991)>
=1991AJ....101.1408M 1991AJ....101.1408M (SIMBAD/NED BibCode)
ADC_Keywords: Associations, stellar ; Photometry, UBV ; Photometry, CCD
Description:
The galactic association Cygnus OB2, which contains heavily reddened
O and B stars, has been studied using CCD UBV photometry and
spectroscopy. The file "mt91.dat" contains precise coordinates, UBV
photometry, and spectral types from the study of Cygnus OB2, and
merges the tables 2, 5 and 6 from the paper.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
mt91.dat 73 801 Observations in Cyg OB2 (tables 2,5,6)
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See also:
J/A+AS/111/407 : VI Cygni red + reddened stars (Parthasarathy+, 1995)
J/AJ/107/1433 : Cygnus OB2 polarimetry (Kobulnicky+, 1994)
J/MNRAS/298/753 : Variables in Cygnus OB2 (Pigulski+ 1998)
Byte-by-byte Description of file: mt91.dat
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Bytes Format Units Label Explanations
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2- 4 I3 --- MT91 [1/799]+? Star identification (1)
8- 9 I2 h RAh Right Ascension J2000 (hours) (2)
11- 12 I2 min RAm Right Ascension J2000 (minutes) (2)
14- 18 F5.2 s RAs Right Ascension J2000 (seconds) (2)
21 A1 --- DE- Declination J2000 (sign) (2)
22- 23 I2 deg DEd Declination J2000 (degrees) (2)
25- 26 I2 arcmin DEm Declination J2000 (minutes) (2)
28- 31 F4.1 arcsec DEs Declination J2000 (seconds) (2)
35- 39 F5.2 mag Vmag ? V magnitude
42- 46 F5.2 mag U-B ? U-B colour derived from B-V
47 A1 --- u_U-B [:?] Uncertainty flag on U-B (3)
49- 53 F5.2 mag B-V ? B-V colour
54 A1 --- u_B-V [:?] Uncertainty flag on B-V (3)
57- 68 A12 --- SpType MK Spectral type (4)
70- 73 A4 --- Rem Remarks (5)
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Note (1): the first two stars in the list were outside the MT91 survey
area, but new spectral types for them were given in Table 6. The
positions for these 2 stars come from the ACT and GSC v1.2, and
agree with those in the table to within an arcsecond or so.
Note (2): positions were computed from original x,y by Brian Skiff,
see the "History" section below
Note (3): the colon ':' indicates a uncertainty greater than 2-sigma,
and the question mark '?' an error greater than 3-sigma (these
were given as a double colon in the source paper)
Note (4): only the MK spectral type determined by Massey & Thompson
is listed here; types from other sources cited in the original
tables were ignored.
Note (5): The Remarks column shows those stars that were blended
('bl') in Massey & Thompson's analysis, and 'traditional' Schulte
numbers (see 1956ApJ...124..530S 1956ApJ...124..530S) indicated in the MT91 tables
(e.g. S 12).
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Nomenclature Notes:
The acronym "MT" is sometimes used to designate the stars from this
list in the literature. MT91 should be preferred.
History:
An electronic copy of Table 2 was prepared by Jean-Claude Mermilliod
(). The star positions were
computed by Brian Skiff () from about 50 stars
scattered across the four CCD fields, for which coordinates were found
from the ACT or GSC version 1.2, plus a few faint stars from
USNO-A1.0, with rms residuals of 0".6.
(End) Brian Skiff [Lowell Obs.], Francois Ochsenbein [CDS] 17-Sep-1998