Ref: ASTROimport-370

Discovery of a TiO emission band in the infrared spectrum of the S star NP Aurigae

Smolders, K. ; Verhoelst, T. ; Neyskens, P. ; Blommaert, J. A. D. L. ; Decin, L. ; Van Winckel, H. ; Van Eck, S. ; Sloan, G. C. ; Cami, J. ; Hony, S. ; De Cat, P. ; Menu, J. ; Vos, J.

published in Astronomy and Astrophysics, 543, pp. L2 (2012)

Abstract: We report on the discovery of an infrared emission band in the Spitzer spectrum of the S-type AGB star NP Aurigae that is caused by TiO molecules in the circumstellar environment. We modeled the observed emission to derive the temperature of the TiO molecules (˜600 K), an upper limit on the column density (˜1017.25 cm-2) and a lower limit on the spatial extent of the layer that contains these molecules. (˜4.6 R?). This is the first time that this TiO emission band is observed. A search for similar emission features in the sample of S-type stars yielded two additional candidates. However, owing to the additional dust emission, the identification is less stringent. By comparing the stellar characteristics of NP Aur to those of the other stars in our sample, we find that all stars with TiO emission show large-amplitude pulsations, s-process enrichment, and a low C/O ratio. These characteristics might be necessary requirements for a star to show TiO in emission, but they are not sufficient.

DOI: 10.1051/0004-6361/201219520
Links: link

The record appears in these collections:
Royal Observatory of Belgium > Astronomy & Astrophysics
Science Articles > Peer Reviewed Articles

 Record created 2016-07-01, last modified 2016-07-06