J/ApJ/452/210 UBV photometry in LH 47/48 (Oey+ 1995)
Triggered star formation and the dynamics of a superbubble in the LMC:
the OB association LH 47/48 in DEM 152
Oey M.S., Massey P.
<Astrophys. J. 452, 210 (1995)>
=1995ApJ...452..210O 1995ApJ...452..210O
ADC_Keywords: Magellanic Clouds ; Associations, stellar ; Photometry, UBV
Keywords: galaxies: star clusters - ISM: bubbles - ISM: individual (DEM 152) -
Magellanic Clouds - stars: formation
Abstract:
We examine the stellar population of an OB association, LH 47/48,
which is associated with a superbubble H II region, DEM 152 in the N44
nebular complex of the Large Magellanic Cloud. With CCD photometry and
spectroscopy of the massive stars, we find no evidence that an unusual
stellar population gave rise to the shell morphology of the gas. The
slope of the initial mass function, Γ=1.3±0.2, is consistent
with that of other OB associations in the LMC, and there is no
significant difference in the initial mass function internal or
external to the supershell. The inferred stellar ionizing flux is
consistent with the observed nebular H alpha flux. We do find evidence
for triggered star formation: the H-R diagram suggests an age of
>10Myr for the population interior to the bubble with more recent,
<5Myr, star formation on the exterior. Using the detailed data on the
stellar population, we compare a numerical form of the Weaver et al.
(1977ApJ...218..377W 1977ApJ...218..377W) evolutionary model for wind-driven bubbles with
the observed shell kinematics. We find a substantial discrepancy: the
observed shell radius is too small and/or expansion velocity too large
to be explained with this version of the model. We discuss possible
explanations for the inconsistency.
Objects:
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RA (2000) DE Designation(s) (File)
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05 22.0 -67 57 LH 47 = HD 35814 = NGC 1935 (table1a.dat)
05 22.5 -67 53 LH 48 = NGC 1937 (table1b.dat)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1a.dat 34 450 Photometry of stars in LH 47
table1b.dat 34 195 photometry of stars in LH 48
table2.dat 98 65 Derived parameter stars with spectral types
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Byte-by-byte Description of file: table1a.dat table1b.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Star Star number ([OM95] LH 47/48 NNN in Simbad)
4 A1 --- m_Star Multiplicity index on Star
6- 10 F5.1 pix Xpos X position
12- 16 F5.1 pix Ypos Y position
18- 22 F5.2 mag Vmag V magnitude
24- 28 F5.2 mag B-V B-V colour index
30- 34 F5.2 mag U-B U-B colour index
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- --- [lh]
3- 9 A7 --- Star Star designation (47-NNN or 48-NNN)
11- 15 F5.1 pix Xpos X position
17- 21 F5.1 pix Ypos Y position
23- 24 I2 h RAh Right ascension (J2000)
26- 27 I2 min RAm Right ascension (J2000)
29- 33 F5.2 s RAs Right ascension (J2000)
35 A1 --- DE- Declination sign
36- 37 I2 deg DEd Declination (J2000)
39- 40 I2 arcmin DEm Declination (J2000)
42- 45 F4.1 arcsec DEs Declination (J2000)
47- 51 F5.2 mag Vmag V magnitude
53- 57 F5.2 mag B-V B-V colour index
59- 63 F5.2 mag U-B U-B colour index
65- 69 F5.2 --- Q Reddening-free parameter (Q=(U-B)-0.72(B-V))
71- 75 F5.3 [K] log(Teff) Effective temperature
76 A1 --- u_log(Teff) [)] Uncertainty flag on log(Teff)
78- 81 F4.1 mag Mbol Bolometric magnitude
82 A1 --- u_Mbol [)] Uncertainty flag on Mbol
84- 85 I2 solMass Mass Star mass
86 A1 --- u_Mass [)] Uncertainty flag on Mass
88- 98 A11 --- SpType MK spectral type
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History:
* 07-Apr-1997: Prepared via OCR at CDS.
* 23-Feb-2006: Corrections in table2 (missing minus signs in col. B-V, U-B, Q)
(End) James Marcout, Patricia Bauer [CDS] 07-Apr-1997