Line-of-sight velocity measurements using a dissector-tube. II. Time variations of the tangential velocity component in the Evershed effect

Details Line-of-sight velocity measurements using a dissector-tube. II. Time variations of the tangential velocity component in the Evershed effect Line-of-sight velocity measurements using a dissector-tube. II. Time variations of the tangential velocity component in the Evershed effect

Sep 1993

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993a%26a...277..242d&link_type=abstract

Astronomy and Astrophysics, Vol. 277, p. 242 (1993)

Astronomy and Astrophysics

Astrophysics

4

The Sun: Sunspots - Oscillations, The Instruments

Scientific paper

We present the results of measurements of sunspot torsional oscillations. For six sunspots, a study was made of the spectral composition of Doppler velocity signals from two areas of penumbra, symmetric about the sunspot umbra located near the limb. The spectrograph slit was directed parallel to the nearest solar limb. The observations were made in the lines Fe i 543.45 nm and Hβ 486.13 nm using a dissector tube. Its electronic scanning was controlled in such a way that two channels measure spectral line shifts in two different parts of the photo-cathode. Attention mainly was paid to periods from 1 min to several hours. The results of the work indicate that the sunspot penumbra exhibits several kinds of oscillations: quasi-five-min vertical oscillations of small areas of penumbra (4 arcsec), vertical oscillations of large areas of penumbra (periods from 20 min to 1 h), and the sunspot torsional oscillations. Periodic variations in sunspot position are observed to have an amplitude of about 1 arcsec and periods close to those of the sunspot torsional oscillations.

Affiliated with

Also associated with

No associations

Rating

Line-of-sight velocity measurements using a dissector-tube. II. Time variations of the tangential velocity component in the Evershed effect 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 Line-of-sight velocity measurements using a dissector-tube. II. Time variations of the tangential velocity component in the Evershed effect, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Line-of-sight velocity measurements using a dissector-tube. II. Time variations of the tangential velocity component in the Evershed effect will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1559020