II/187A 30 Doradus OB Associations (Parker 1992)
30 Doradus in the Large Magellanic Cloud: The Stellar Content and
Initial Mass Function
Parker, J. W.
<Publ. Astron. Soc. Pac. 104, 1107 (1992)>
<Astron. J. 106, 560 (1993)>
<Astron. J. 106, 1471 (1993)>
=1992PASP..104.1107P 1992PASP..104.1107P
=1993AJ....106..560P 1993AJ....106..560P
=1993AJ....106.1471P 1993AJ....106.1471P
ADC_Keywords: Magellanic Clouds; Clusters, open; Photometry, UBV
Abstract:
Johnson UBV photometry is presented for 2395 stars in the OB
associations of 30 Doradus in the Large Magellanic Cloud. The
CCD fields cover an area of 50 square arcminutes in the central
region. The entire catalog (exclusive of the dense core cluster R136)
is photometrically complete to V=B=18mag and U=17mag, although the
completeness magnitudes are fainter for regions with less nebular
contamination.
Description:
These data have been reduced from 39 CCD frames (with short, medium,
and long exposure times ranging from 3 to 1000 seconds) using the
photometry program DAOPHOT (Peter Stetson, 1987PASP...99..191S 1987PASP...99..191S). The
photometric errors listed in these tables are the errors derived by
DAOPHOT using the relative magnitude of the star on the CCD and the
goodness of the fit of the point spread function. Most stars appear
on more than one CCD frame per filter, and their resulting tabulated
magnitudes are the averages of the individual measurements inversely
weighted by the squares of their errors.
The stars in these tables are from two regions: the central region
and a non-overlapping northern region. The latter are designated
by four digit numbers starting with 9. The X,Y coordinates are the
positions relative to the northwestern-most corner of each region.
Notes and remarks (B. Skiff):
Precise coordinates on the ICRS system were determined by B. Skiff in
March 2008, by identifying 68 relatively bright and isolated stars in
either UCAC2 (Cat. I/289) or 2MASS (Cat. II/246). The x,y coordinates
were transformed using a quadratic least-squares fit, giving resulting
rms residuals of 0.14arcsec. A separate reduction was done on the
'north' field (stars numbered 9001-9045), which gave similar results
from a linear fit. It should be noticed too that in the original
table 5, the positions are offset by three lines, such that, for
example, the bright star 9009 actually has the coordinates of star
9006. This error has been removed in this revised version.
(The coordinates for these stars are correct in Tables 11 and 12.)
It was apparent while checking the data for individual stars that
the catalogue includes false detections. This was first discussed by
Parker & Garmany (1993AJ....106.1471P 1993AJ....106.1471P, sec 3.2 and Figure 5) shortly
after the catalogue itself was published. Many of the faint entries
having V≳17 result from the star-finding algorithm having picked up
small clumps in the overlying nebulosity. Among the distinguishing
characteristics of the false entries are non-physical photometric
colors. Rubio et al (1998AJ....116.1708R 1998AJ....116.1708R) also report that a match-up
of HST images against the Parker list shows blank sky at the positions
for most of the faintest stars.
The original data can be retrieved from the file "tables.ori".
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
photo.dat 106 2395 Positional and photometric data (tables 4 and 5)
spectro.dat 125 302 Spectroscopic data (tables 11 and 12)
tables.ori 134 3178 Original data material from J.W. Parker
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See also:
J/A+A/341/98 : The ionizing cluster of 30 Doradus. I. (Selman+ 1999)
J/A+A/443/851 : Effective temperature of 30 Dor population (Selman+, 2005)
J/AJ/107/1054 : UBV photometry of the 30 Dor region (Malumuth+, 1994)
Byte-by-byte Description of file: photo.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
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3- 6 I4 --- Num [1/9045] Running number ([P93] in Simbad)
11- 12 I2 h RAh Right ascension J2000 (1)
14- 15 I2 min RAm Right ascension J2000 (1)
17- 22 F6.3 s RAs Right ascension J2000 (1)
24 A1 --- DE- Declination sign J2000 (1)
25- 26 I2 deg DEd Declination J2000 (1)
28- 29 I2 arcmin DEm Declination J2000 (1)
31- 35 F5.2 arcsec DEs Declination J2000 (1)
38- 43 F6.2 pix Xpos X position (2)
46- 52 F7.2 pix Ypos Y position (2)
56- 61 F6.3 mag Vmag V magnitude, in Johnson system
65- 70 F6.3 mag B-V B-V color, in Johnson system
74- 79 F6.3 mag U-B ?=99.000 U-B color, in Johnson system (3)
84- 88 F5.3 mag e_Vmag Vmag accuracy
93- 97 F5.3 mag e_B-V B-V accuracy
102-106 F5.3 mag e_U-B ?=9.000 U-B accuracy
--------------------------------------------------------------------------------
Note (1): Position recomputed in March, 2008, see some details in the
"Notes and remarks" section above.
Note (2): coordinates are from the CCD finder charts in the reference.
Pixel sizes (in X and Y columns) are approximately 0.49arcsec/pixel
Note (3): 99.000 indicates no value for U-B.
Note that most of the stars having U-B < -1.3 tend to have large
errors in U because they are relatively faint or are blended
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Byte-by-byte Description of file: spectro.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanation
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1- 5 I5 --- Num [1/9045] Running number (7)
6 A1 --- n_Num [r] indicates a star too faint or red (7)
7- 8 I2 h RAh Original Right ascension 2000 (1)
10- 11 I2 min RAm Original Right ascension 2000 (1)
13- 16 F4.1 s RAs Original Right ascension 2000 (1)
19 A1 --- DE- Original Declination sign 2000 (1)
20- 21 I2 deg DEd Original Declination 2000 (1)
23- 24 I2 arcmin DEm Original Declination 2000 (1)
26- 27 I2 arcsec DEs Original Declination 2000 (1)
31- 35 F5.1 pix Xpos X position
39- 43 F5.1 pix Ypos Y position
46- 50 F5.2 mag Vmag V magnitude in Johnson system
53- 57 F5.2 mag B-V B-V color in Johnson system
60- 64 F5.2 mag U-B U-B color in Johnson system
67- 71 F5.2 mag Q Q = (U-B) - 0.72(B-V)
75- 78 F4.2 mag E(B-V) Color excess in B-V calculated from Q
81- 85 F5.2 mag Mv Absolute V magnitude (2)
88- 91 F4.2 [K] Teff Log effective temperature (3)
93- 98 F6.2 mag Mbol Bolometric absolute magnitude (4)
101-112 A12 --- Sp MK spectral type (5)
115-125 A11 --- Com Comments (6)
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Note (1): a more accurate position is available from the "photo.dat" file,
see the "Notes and remarks" section above.
Note on (2): Mv is the absolute V magnitude = V - Rv * E(B-V) - DM where
Rv = 3.1, and the distance modulus DM = 18.5 mag.
Note (3): is the log10 of the effective temperature, and is
calculated from Q or (B-V)0 as discussed in Section 3.1 of Paper II
(1993AJ....106.1471P 1993AJ....106.1471P)
Note (4): is the bolometric magnitude = Mv + BC, where BC is
calculated from Teff as discussed in Section 3.1 of Paper II
(1993AJ....106.1471P 1993AJ....106.1471P)
Note (5): Sp is the spectral type and luminosity class as determined from
spectroscopic observations. One colon ":" indicates an uncertainty
of one spectral subtype or luminosity class, and two colons "::"
indicate a larger uncertainty.
Note (6): Comments are indicated by the following codes:
a = strong / over-subtracted Balmer lines
b = blend
c = possible composite / spectrum contaminated by nearby star
e = strong nebular emission in the Balmer lines
f = foreground star
j = has been observed by the author and the spectrogram appears
in Figure 6 or 7 of Paper I (1993AJ....106..560P 1993AJ....106..560P)
J = as j, with spectral type agreement.
p = peculiar (details in text of Paper I, 1993AJ....106..560P 1993AJ....106..560P)
m = has been observed by Melnick (1985A&A...153..235M 1985A&A...153..235M)
M = as m, with spectral type agreement.
w = has been observed by Walborn (1986, IAU Symp. 116, 185;
1992 - unpublished classifications) or Walborn & Blades
(1987ApJ...323L..65W 1987ApJ...323L..65W)
W = as w, with spectral type agreement.
z = ZAMS O star
The uppercase letters "J", "M", "W", indicate the sources of the
spectral types listed in the 'Sp' column; two or all three letters
may be uppercase if they agree on the same classification.
Note (7): stars without the suffix 'r' are the Bluest (Q←0.7) and
Brightest (V<16) Stars in 30 Doradus.
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Courtesy:
Joel Parker <joel(at)hrssun.gsfc.nasa.gov>
Historical Notes:
* 17-May-1994: First archived (Nancy G. Roman, NASA/NSSDC/ADC)
* 15-Mar-1995: Corrected reference (PASP 104) and standardized this file (CDS)
* 20-Jul-1995: Removed the colons (:) between RAh:RAm:RAs and DEd:DEm:DEs
in data files (Francois Ochsenbein, CDS)
* 05-Mar-2008: accurate position by B. Skiff in the photo.dat file
(catalog renumbered II/187A)
(End) Joel Parker, Nancy G. Roman, Brian Skiff, Francois Ochsenbein 05-Mar-2008