Variable Bump Extinction in NGC6530
Abstract
We have found that the area and width of the 2200 A ultraviolet extinction bump varies dramatically from star to star within the young cluster NGC 6530. The bump is strongest toward stars in the center of the cluster and systematically weakens with distance from center appearing to reach an asymptotic state. Because the highest temperature stars in our sample are generally farther from the center this may also mean that the extinction bump is dependent on stellar temperature. It is very unfortunate that five stars whose positions and/or temperatures make them well suited for separating the effects of distance and temperature have only low quality long wavelength spectra. We want to reobserve those stars and obtain spectra of new targets advantageously located within the cluster to study whether the extinction is dependent on distance from the center or on stellar temperature.
- Publication:
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IUE Proposal
- Pub Date:
- 1989
- Bibcode:
- 1989iue..prop.3372B