Latitude-Dependent Temperature Variations at the Solar Limb

Details Latitude-Dependent Temperature Variations at the Solar Limb Latitude-Dependent Temperature Variations at the Solar Limb

May 2009

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009spd....40.0925f&link_type=abstract

American Astronomical Society, SPD meeting #40, #9.25; Bulletin of the American Astronomical Society, Vol. 41, p.821

Astronomy and Astrophysics

Astronomy

Scientific paper

We use observations from the solar aspect sensor of RHESSI to characterize the latitude dependence of the temperature of the photosphere at the solar limb. Previous observations have suggested the presence of a polar temperature excess as large as 1.5 K. The RHESSI observations, made with a rotating telescope in space, have great advantages in the rejection of systematic errors in the very precise photometry required for such an observation. This photometry is differential, i.e. relative to a mean limb-darkening function. The data base consists of about 1,000 images per day from linear CCDs with 1.73 arc sec square pixels, observing a narrow band (12nm FWHM) at 670 nm. Each image shows a chord crossing the disk at a different location as the spacecraft rotates and precesses around its average solar pointing. We fit an average limb-darkening function and reassemble the residuals into synoptic maps of differential intensity variations as function of position angle. We further mask these images against SOHO/EIT 284A images in order to eliminate magnetic regions. The analysis establishes limits on the quadrupole dependence of brightness (temperature) on position angle, a crucial unknown in our precise measurement of the solar oblateness.

Affiliated with

Also associated with

No associations

Rating

Latitude-Dependent Temperature Variations at the Solar Limb 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 Latitude-Dependent Temperature Variations at the Solar Limb, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Latitude-Dependent Temperature Variations at the Solar Limb will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1112092