Coronal Rotation at Solar Minimum from UV Observations

Details Coronal Rotation at Solar Minimum from UV Observations Coronal Rotation at Solar Minimum from UV Observations

Nov 2008

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008apj...688..656g&link_type=abstract

The Astrophysical Journal, Volume 688, Issue 1, pp. 656-668.

Astronomy and Astrophysics

Astronomy

13

Sun: Corona, Sun: Rotation, Sun: Uv Radiation

Scientific paper

The observations of the UVCS SOHO instrument from 1996 May to 1997 May have been analyzed to reconstruct intensity time series of the O VI 1032 Å and H I Lyα 1216 Å spectral lines at different coronal heliolatitudes from 1.5 to 3.0 Rsolar from Sun center. At solar minimum, some features persist for several rotations, thus allowing analysis of the UV emission as time series modulated at the period of the solar rotation. We find evidence of coronal differential rotation, which significantly differs from that of the photospheric plasma. The estimated equatorial synodic rotation period of the corona at 1.5 Rsolar is 27.48+/-0.10 days. The study of the latitudinal variation shows that the UV corona decelerates toward the photospheric rates from the equator up to the poleward boundary of the midlatitude streamers, reaching a peak of 28.16+/-0.20 days around +30° from the equator at 1.5 Rsolar, while a less evident peak is observed in the northern hemisphere. This result suggests a real north-south rotational asymmetry as a consequence of different activity and weak coupling between the magnetic fields of the two hemispheres. The study of the radial rotation profiles shows that the corona is rotating almost rigidly with height, but we find an abrupt increase by about half a day between 2.3 and 2.5 Rsolar. The larger gradients of the rotation rates are localized at the boundaries between open and closed field lines, suggesting that in these regions the differential rotation might be a source of magnetic stress and, consequently, of energy release.

Affiliated with

Also associated with

No associations

Rating

Coronal Rotation at Solar Minimum from UV Observations does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Coronal Rotation at Solar Minimum from UV Observations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Coronal Rotation at Solar Minimum from UV Observations will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1842276