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We compare high-resolution ultraviolet spectra of the Sun and thirteensolarmass main sequence stars with different rotational periods that serve asproxies for their different ages and magnetic field structures. In this thesecond paper in the series, we study the dependence of ultravioletemission-line centroid velocities on stellar rotation period, as rotation ratesdecrease from that of the Pleiades star HII314 (Prot = 1.47 days) to Alpha CenA (Prot = 28 days). Our stellar sample of F9 V to G5 V stars consists of sixstars observed with the Cosmic Origins 1Guest Observer, NASA/ESA Hubble SpaceTelescope and User of the Data Archive at the Space Telescope ScienceInstitute. Spectrograph on HST and eight stars observed with the SpaceTelescope Imaging Spectrograph on HST. We find a systematic trend of increasingredshift with more rapid rotation (decreasing rotation period) that is similarto the increase in line red shift between quiet and plage regions on the Sun.The fastest-rotating solar-mass star in our study, HII314, shows significantlyenhanced redshifts at all temperatures above log T = 4.6, including the corona,which is very different from the redshift pattern observed in the moreslowly-rotating stars. This difference in the redshift pattern suggests that aqualitative change in the magnetic-heating process occurs near Prot = 2 days.We propose that HII314 is an example of a solar-mass star with a magneticheating rate too large for the physical processes responsible for the redshiftpattern to operate in the same way as for the more slowly rotating stars.HII314 may therefore lie above the high activity end of the set of solar-likephenomena that is often called the "solar-stellar connection".

Ultraviolet Spectroscopy of Rapidly-Rotating Solar-Mass Stars: Emission Line Redshifts as a Test of the Solar-Stellar Connection