Absolute Magnitudes and Colors of A--F Supergiants from Near Infrared Features
Session 17 -- Stellar Spectroscopy and Photometry: Surveys and General results
Display presentation, Wednesday, January 12, 9:30-6:45, Salons I/II Room (Crystal Gateway)

## [17.12] Absolute Magnitudes and Colors of A--F Supergiants from Near Infrared Features

Donald J. Slowik, Deane M. Peterson (SUNY @Stony Brook)

We consider the calibration of luminosities and intrinsic colors of A and F supergiants in terms of near infrared features. We calibrate ${\rm M_V}$ in terms of the equivalent width of the ${\rm O\thinspace{\tenrm I} \thinspace\lambda 7774}$ feature from a sample of 14 stars in 13 Galactic clusters. The rms dispersion about this relation is $\sim$0.5 mag.

Using this same sample, plus one association member, we calibrate ${\rm(B-V)_\circ}$ in terms of the strength of the infrared Calcium triplet. The rms dispersion about this relation is 0.056 mag.

We investigate these relations with a large sample of A and F supergiants in the Magellanic Clouds. The possibility of using these luminous stars as standard candles is discussed.