SOTSP: HOP 393
2022-06-25T00:34:30 to 2022-06-25T01:38:30
Science Goal: Cycle 24/25 equatorial transition
Program: Fast Map, Full FOV 1 side CCD Q75
Target: Quiet Sun
xcen=-16 ycen=-107
Instrument: SOTSP
HOP/JOP: 393
Description:
Main Objective: Capture the magnetic and chromospheric signatures of the transition between cycle 24 and 25. Scientific Justification: Small magnetic features and coronal bright points have been shown to indicate the bands of activity associated with the solar cycle. The precise location of these bands is important for predicting the timing of solar minimum and, more generally, the long-term variability of the Sun. The termination of equatorward-propogating activity bands at the solar equator has been identified as a key event of the solar cycle (McIntosh et al. 2014, McIntosh and Leamon 2017, McIntosh et al. 2019). Using the record of cycle 24 activity, Leamon et al. 2019 have predicted the cycle 24/25 terminator event to occur in May 2020, with +5 month/-1.5 month uncertainty. SDO observations of the previous cycle 23/24 terminator event showed a nearly step-function-like increase in coronal bright point density and emission in various SDO/AIA bandpasses in the high-latitude, new cycle bands when compared to the low-latitude, old cycle bands. The flux changes across the terminator event were found to increase in proportion to the temperature of formation of the radiation. We propose a new set of synoptic observations of the solar equator to complement the high-latitude observations of IHOP 336 ("Cycle 25 Bright Points") in order to capture the solar cycle 24/25 terminator event. Hinode SP measurements will give us high resolution vector field data, and IRIS will show the chromospheric spectral signature of the bright points, characteristics that are not available with SDO/AIA and HMI. As a complement to the IHOP 336 dataset, we aim to find comparative differences between the developing activity of the new solar cycle with the diminishing activity of the old solar cycle around the time of transition. McIntosh, S. W., et al., 2014, ApJ, 792, 12 McIntosh, S. W. and Leamon, R. J., 2017, Frontiers in Astronomy and Space Sciences, 4, 4 McIntosh, S. W. et al., 2019, Solar Physics, 294, 7, 88 Leamon et al. 2019, Solar Physics, submitted [arXiv:1909.06603]
