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| Paper: |
Solar Oscillations in CO at 4.6 Microns |
| Volume: |
135, A Half Century of Stellar Pulsation Interpretations: a Tribute to Arthur N. Cox |
| Page: |
186 |
| Authors: |
Livingston, W.; Solanki, S.; Muglach, K.; Wallace, L. |
| Abstract: |
The fundamental band lines of CO originate in the solar temperature minimum and lower cool parts of the chromosphere. We have observed velocity and intensity oscillations in the quiet sun disk center and extreme limb, sunspots, and plage. We have also looked for CO oscillations in the Sun-as-a-star (but detect nothing). We compare the power spectra of these various features, noting well separated 3 min and 5 min peaks. We interpret our observations in terms of the models of Carlsson and Stein (1995), and Solanki, et al., (1994). Active Region Seismology: Results from TON Project Bala Balachandran (Dept. Physics, National Tsing Hua University, Hsinchu, Taiwan 30043, R.O.C.) Taiwan Oscillation Network (TON) is a ground based observation facility for the study of solar oscillations. The data consists of full-disc K-line images taken at every minute. Using the 512 images time series, we have tried to infer the location of the magnetic field below the photosphere using the property of the active regions to absorb the p-mode power. Two consecutive days, one just when the magnetic flux appears on the surface and the other the day before the emergence, were analysed. For this, an annular region of 15 deg. around the region of emerging flux was chosen for the analysis. The modes were decomposed into incoming and outgoing waves and the absorption coefficient was calculated as the fractional difference of the two types. We found that the absorption is stronger after the emergence of the flux and the flux was at a depth of about 4000 km below the surface just before its appearance on the surface; that is about 15 hrs before. It was also reported earlier by other groups that the quiet sun exhibits acoustic emission. It is believed to be an observational effect and the cause is yet to find out. We have carried out a systematic analysis of the quiet sun emission using 512 images. The analysis is similar to the active region study, but the region of interest is the solar disc centre. We found that there exists negative absoption or emission for most modes and the negative absorption increases with the angular distance from the centre of the sun. |
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