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H? Equivalent Width Variations Across the Face of a Microlensed K Giant in the Galactic Bulge


Albrow, MD and An, J and Beaulieu, JP and Caldwell, JAR and Dominik, M and Greenhill, JG and Hill, KM and Kane, S and Martin, R and Menzies, J and Pollard, K and Sackett, PD and Sahu, KC and Vermaak, P and Watson, RD and Williams, A and Hauschildt, PH, H? Equivalent Width Variations Across the Face of a Microlensed K Giant in the Galactic Bulge, The Astrophysical Journal, 550, (2) pp. L173-L177. ISSN 0004-637X (2001) [Refereed Article]

DOI: doi:10.1086/319635


We present Very Large Telescope FORS1 spectroscopy that temporally resolves the second caustic crossing of the Galactic bulge K giant source of microlensing event EROS 2000-BLG-5, the first time this has been accomplished for several phases of a caustic transit. The ∼1 ÅHα equivalent width of the source star increases slightly as the center of the star egresses the caustic and then plummets by 30% during the final limb crossing. These changes are not seen in contemporaneous spectra of control stars in the FORS1 slit but are qualitatively consistent with expectations from stellar atmosphere models as the caustic differentially magnifies different portions of the stellar face of the target. Observations such as these in a variety of stellar lines are equivalent to atmospheric tomography and are expected to provide a direct test of stellar models.

Item Details

Item Type:Refereed Article
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Galactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Greenhill, JG (Dr John Greenhill)
UTAS Author:Hill, KM (Dr Kym Hill)
UTAS Author:Kane, S (Dr Stephen Kane)
UTAS Author:Watson, RD (Dr Bob Watson)
ID Code:22123
Year Published:2001
Web of Science® Times Cited:25
Deposited By:Physics
Deposited On:2001-08-01
Last Modified:2002-07-02

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