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Published November 1997 | Published
Journal Article Open

Far-Ultraviolet Imaging of the Large Magellanic Cloud Populous Cluster NGC 1978 with WFPC2


We have imaged the ~2.2 billion-year-old Large Magellanic Cloud populous cluster NGC 1978 in the far-ultraviolet and visible with the second Wide Field/Planetary Camera (WFPC2) on the Hubble Space Telescope. The far-ultraviolet images show a sparse stellar field with little apparent density enhancement in the cluster core. The visible images are dominated by the cluster's first-ascent and second-ascent red giants, which are completely invisible to the far-ultraviolet filter. No evidence for a hot horizontal branch population of core-helium-burning stars is seen; nor is there any apparent indication of a significant blue straggler population. These results suggest that the presence of a rich, young population of field stars in the NGC 1978 region is responsible for the unusual location of the cluster in the integrated light color-color plots produced by IUE.

Additional Information

© 1997 American Astronomical Society. Provided by the NASA Astrophysics Data System. Received 1997 June 18; revised 1997 August 4; accepted 5 August 1997. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. This research was carried out by the WFPC2 Investigation Definition Team for JPL and was sponsored by NASA through Contract No. NAS 7-1260. A preliminary version of these results was presented in poster format at the VIII Canary Islands Winter School: "Stellar Astrophysics For the Local Group," which was held in La Laguna, Spain, during 1996 December 2-13. A.A.C. would like to thank the participants in the Winter School for many critical readings, questions, and suggestions which improved the discussion of the results as presented in this paper.

Attached Files

Published - 1997AJ____114_1945C.pdf


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August 19, 2023
October 19, 2023