Simulating the Role of Stellar Rotation in the Spectroscopic Effects of Differential Limb Magnification

Adam R. H. Stevens, Michael D. Albrow

Research output: Contribution to journalArticlepeer-review


Finite-source effects of gravitationally microlensed stars have been well discussed in the literature, but the role that stellar rotation plays has been neglected. A differential magnification map applied to a differentially Doppler-shifted surface alters the profiles of absorption lines, compromising their ordinarily symmetric nature. Herein, we assess the degree to which this finite-source effect of differential limb magnification (DLM), in combination with stellar rotation, alters spectroscopically derived stellar properties. To achieve this, we simulated a grid of high-magnification microlensing events using synthetic spectra. Our analysis shows that rotation of the source generates differences in the measured equivalent widths of absorption lines supplementary to DLM alone, but only of the order of a few per cent. Using the wings of Hα from the same simulated data, we confirmed the result of Johnson and colleagues that DLM alters measurements of effective temperature by ≲100 K for dwarf stars, while showing rotation to bear no additional effect....
Original languageUndefined/Unknown
JournalPublications of the Astronomical Society of Australia
Publication statusPublished - Nov 2013
Externally publishedYes

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