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Paper: Measuring the Projected Rotational Velocity of KPD 1930+2752
Volume: 348, Astrophysics in the Far Ultraviolet: Five Years of Discovery with FUSE
Page: 227
Authors: Godard, B.; Chayer, P.; Fontaine, G.; Dixon, W.V.; Dupuis, J.; Kruk, J.W.
Abstract: We present a method to measure the projected rotational velocity v sin i of the subdwarf B star KPD 1930+2752 using FUSE time tag observations. This star, which is part of a unique close binary system, undergoes acoustic mode pulsations and is ellipsoidally distorted by the presence of an unseen white dwarf companion. One of our goals is to verify that KPD 1930+2752 is a genuine progenitor of a Type Ia supernova as previously suggested by a British group. To do so, we estimate the mass of the system by modeling the ellipsoidal light curve in terms of the basic parameters of the two stellar components and a value of the sdB's v sin i. However, the measurement of v sin i requires that we remove the star projected orbital velocity (348 km s−1), which inevitably smears out the photospheric lines. This can be done by using FUSE time tag data.
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