Solar and Heliospheric Observatory Ultraviolet Coronagraph Spectrometer and Yohkoh Soft X-Ray Telescope Observations of the High-Temperature Corona above an Active Region Complex

Details Solar and Heliospheric Observatory Ultraviolet Coronagraph Spectrometer and Yohkoh Soft X-Ray Telescope Observations of the High-Temperature Corona above an Active Region Complex Solar and Heliospheric Observatory Ultraviolet Coronagraph Spectrometer and Yohkoh Soft X-Ray Telescope Observations of the High-Temperature Corona above an Active Region Complex

Oct 2002

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002apj...578..979k&link_type=abstract

The Astrophysical Journal, Volume 578, Issue 2, pp. 979-995.

Astronomy and Astrophysics

Astronomy

22

Sun: Abundances, Sun: Corona, Sun: Uv Radiation

Scientific paper

We present the results of Solar and Heliospheric Observatory Ultraviolet Coronagraph Spectrometer (SOHO/UVCS) and Yohkoh Soft X-Ray Telescope (SXT) observations above an active region complex (AR 8194, 8195, and 8198) at the southeast limb on 1998 April 6-7. This active region complex appears to be the base of a small streamer seen by the Large Angle and Spectrometric Coronagraph Experiment (LASCO/C2) at the southeast limb. The UVCS was offset-pointed to observe low in the corona from 1.22 up to 1.6 Rsolar with normal pointing. High-temperature lines such as [Fe XVIII] λ974 and Ne IX λ1248 were present in this region, implying that the electron temperature is higher than that in the quiet-Sun corona. This region of the corona is also seen as particularly bright in the Yohkoh/SXT, SOHO EUV Imaging Telescope high-temperature filter (Fe XV λ284) and SOHO/LASCO C1. The electron temperature analysis indicates a two-temperature structure, one of ~1.5×106 K, which is similar to that observed in quiet-Sun streamers, and the other at a high temperature of ~3.0×106 K. This two-temperature region likely corresponds to two distinct coronal regions overlapping in the line of sight. We compare the electron temperature and emission measure results from the SOHO/UVCS data with those from the Yohkoh/SXT data. The absolute elemental abundances show a general first ionization potential effect and decrease with height for all the elements. This is consistent with the effect of gravitational settling, which, however, cannot totally account for the observed elemental abundances. Other mechanisms that are likely to affect the coronal elemental abundance are discussed.

Affiliated with

Also associated with

No associations

Rating

Solar and Heliospheric Observatory Ultraviolet Coronagraph Spectrometer and Yohkoh Soft X-Ray Telescope Observations of the High-Temperature Corona above an Active Region Complex 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 Solar and Heliospheric Observatory Ultraviolet Coronagraph Spectrometer and Yohkoh Soft X-Ray Telescope Observations of the High-Temperature Corona above an Active Region Complex, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Solar and Heliospheric Observatory Ultraviolet Coronagraph Spectrometer and Yohkoh Soft X-Ray Telescope Observations of the High-Temperature Corona above an Active Region Complex will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1660759