Decomposition history of the LMC cluster Sk-66°41
Sk-66°41 in the Large Magellanic Cloud (LMC) was once believed to be one of the most massive stars with a mass over 120 Solar masses. However, on the basis of sharp images obtained in good seeing conditions (0".8 FWHM) and using a high-resolution CCD detector, assisted by an advanced image restoration algorithm, M. Heydari-Malayeri, P. Magain, and M. Remy (1988, A&A 201, L41) showed that Sk-66°41 is actually a star cluster made up of at least 6 stars, the main one having about 90 Solar masses. See also the ESO Press Release.
Left: the original image obtained at the ESO 2.2 m telescope using an R filter; right: the same image after deconvolution showing for the first time that Sk-66°41 is in fact a cluster of at least 6 components.
Field about 3".9 × 3".9.
Subsequently, adaptive optics (COME-ON-PLUS) observations at the ESO 3.6 m telescope in the near infrared JHK bands resolved Sk-66°41 into a cluster of at least 12 componenets (M. Heydari-Malayeri & J.-L. Beuzit, 1994, A&A 287, L17).
An image of the Sk-66°41 cluster in the K band obtained using an adaptive optics system
at the ESO 3.6 m telescope. Field 3".9 × 3".9. Left: the original imege, right: the same image after deconvolution by Richardson-Lucy method, revealing 12 components.
More recently, based on imaging at the ESO NTT telescope and using a very efficient image analysis algorithm (P. Magain, F. Courbin, and S. Sohy, 1998), we have pushed the decomposition of Sk-66°41 still further, resolving it into 15 components. Photometry and color-magnitude diagrams indicate that the components are all massive stars.
and an Strömgren b filter. Field size the same as above. Left: the original image, right: the same image after using the MCS deconvolution algorithm. The cluster is now resolved into at least 15 stars.
M. Heydari-Malayeri, P. Royer, G. Rauw, and N.R. Walborn, 2000, A&A 361, 877
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