Astron. Astrophys. 353, L21-L24 (2000)

4. Conclusions

We present the ISOCAM observations of a new infrared object in the field of the young populous cluster NGC 330 in the Small Magellanic Cloud. The discovered IR object which has been previously identified as a variable star shows a prominent mid-IR excess, indicating the presence of a dust shell. This along with the strong H emission makes the suggestion that this object may be a low-mass Cepheid rather unlikely. We suggest instead that this object may be a low mass field post-AGB star in a proto-planetary nebula stage or a Be supergiant belonging to cluster NGC 330. In both cases the expected optical extinction is relatively high (). We also can not reject the possibility that this object may be an isolated Herbig Ae/Be star. Unfortunately, presently available observations do not allow to distinguish between these scenarios clearly. Neither the basic stellar parameters of the detected object, nor the physical conditions in the H and dust emitting regions can be constrained precisely yet. Therefore, further photometric observations in the UV, near-IR and far-IR, and especially optical spectroscopy would be a highly desirable second step towards clarifying the nature of MIR1.

© European Southern Observatory (ESO) 2000

Online publication: January 18, 2000
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