THE A-X INFRARED BANDS OF ALUMINUM OXIDE IN STARS: SEARCH AND NEW DETECTIONS
2012 (English)In: Astrophysical journal Letters, ISSN 2041-8205, Vol. 753, no 1, L20- p.Article in journal (Refereed) Published
We describe a search for the A-X infrared bands of AlO with a view toward better understanding the characteristics of this radical. These bands are infrequently encountered in astronomical sources but surprisingly were very prominent in the spectra of two well-known, novalike variables (V838 Mon and V4332 Sgr) thereby motivating us to explore the physical conditions necessary for their excitation. In this study, we present the detection of A-X bands in the spectra of 13 out of 17 stars, selected on the basis of their J-K colors as potential candidates for detection of these bands. The majority of the AlO detections are in asymptotic giant branch (AGB) stars, viz., nine OH/IR stars, two Mira variables, and two bright infrared sources. Our study shows that the A-X bands are fairly prevalent in sources with low temperature and O-rich environments. Interesting variation in the strength of the AlO bands in one of the sources (IRAS 18530+0817) is reported and the cause for this is examined. Possible applications of the present study are discussed in terms of the role of AlO in alumina dust formation, the scope for estimating the radioactive Al-26 content in AGB stars from the A-X bands, and providing possible targets for further mm/radio studies of AlO which has recently been discovered at millimeter wavelengths.
Place, publisher, year, edition, pages
2012. Vol. 753, no 1, L20- p.
infrared: stars, ISM: molecules, stars: AGB and post-AGB, techniques: spectroscopic
Astronomy, Astrophysics and Cosmology
IdentifiersURN: urn:nbn:se:kth:diva-99218DOI: 10.1088/2041-8205/753/1/L20ISI: 000305637900020ScopusID: 2-s2.0-84862644932OAI: oai:DiVA.org:kth-99218DiVA: diva2:541997
QC 201207272012-07-272012-07-232012-07-27Bibliographically approved