  In a study of Chandra High Energy Transmission Grating spectra of Algol, we
clearly detect Doppler shifts caused by the orbital motion of Algol B. These
data provide the first definitive proof that the X-ray emission of Algol is
dominated by the secondary, in concordance with expectations that Algol A (B8)
is X-ray dark. The measured Doppler shifts are slightly smaller than expected,
implying an effective orbital radius of about 10 Rsolar, instead of 11.5 Rsolar
for the Algol B center of mass. This could be caused by a small contribution of
X-ray flux from Algol A (10-15%), possibly through accretion. The more likely
explanation is an asymmetric corona biased toward the system center of mass by
the tidal distortion of the surface of Algol B. Analysis of the strongest lines
indicates excess line broadening of ~150 km/s above that expected from thermal
motion and surface rotation. Possible explanations include turbulence, flows or
explosive events, or rotational broadening from a radially extended corona. We
favor the latter scenario and infer that a significant component of the corona
at temperatures <10^7 K has a scale height of order the stellar radius. This is
supported by the shape of the X-ray lightcurve and the shallow dip at secondary
eclipse. We also examine the O VII intercombination and forbidden lines in a
Low Energy Transmission Grating Spectrograph observation and find no change in
their relative line fluxes as the system goes from quadrature to primary
eclipse. Since these lines are strongly affected by UV irradiation from Algol
A, this supports the conjecture that the corona of Algol B at temperatures of
several million K must be significantly extended and/or located toward the
poles to avoid being shadowed from Algol A during primary eclipse.
