HOP 0408

plan term

ToO
2020/12/01-2020/12/07
2020/12/15-2020/12/15
2020/12/19-2020/12/19
2020/12/24-2020/12/27
2021/02/24-2021/02/24
2021/03/03-2021/03/03

abstract of observational proposal

Main Objective: To obtain IRIS spectral observations of coronal jets visible in XRT X-ray images.

Scientific Justification: Many coronal jets (Shibata, K., et al. 1992, PASJ, 44, L173 ) appear to result from the eruption of a small-scale filament (“minifilament”; Sterling, A. C., et al. 2015, Nature, 523, 437). We will test this idea by observing coronal jets spectroscopically, to look for line-shifted erupting-minifilament material. Because the minifilaments have widths of just a few arcseconds (Panesar, N. K., et al. 2016, ApJ, 832L,7), IRIS is an appropriate instrument for these investigations.

request to XRT

TARGET: On-disk coronal hole, or quiet Sun region.
TIMING: Request >~ 4 hours (longer if possible) on the target location.
FIELD OF VIEW: 512x512 desired (384x384 acceptable)
EXPOSURE TIME: Long exposure time (AEC setting = 2)
FILTERS: Al/poly and Al/mesh.
CADENCE: About 30 seconds between images would be acceptable.
IRIS requests:
CH/QS jets with SOT
Repeated scans requested.
OBS 3645202860: Very large sparse 64-step raster binned
Tracking on.
Roll angle of the slit: 0

As described earlier, scan close to the disk center (preferably in a coronal hole but quiet Sun is fine), within 45 degrees from the solar disk center.

request to EIS

An appropriate program is the study “alignment_266,” consisting of 266”-wide EIS “slot” images in “sit and stare” mode and covering five wavelength bands, Fe xii, Fe xiii, He ii, Si x, and Fe xv, taken with a cadence of 124 (as run for the observations in Sterling, A. C., et al. 2010, ApJ, 722, 1644).

other participating instruments

edited on 2020.11.27
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IRIS Request:

CH/QS jets with SOT
Repeated scans requested.
OBS 3645202860: Very large sparse 64-step raster binned
Tracking on.
Roll angle of the slit: 0
As described earlier, scan close to the disk center (preferably in a coronal hole
but quiet Sun is fine), within 45 degrees from the solar disk center.
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Standard data from SDO will be used, including magnetic field data from HMI.

remarks

Dates: Target of Opportunity (ToO).

Time window: Although coronal jets are fairly common features, with an occurrence rate of about 60/day in polar coronal holes (Savcheva, A., et al. 2007, PASJ, 59S, 771S), the timing and location of their occurrence cannot be determined with certitude beforehand. Accordingly, we will select and target promising locations, and continue the observations for as long as practical for the given observation plan. A minimum time period would be four hours, while six hours (or longer) is desirable.

Target(s) of interest: An on-disk target is required, preferably within 45 degrees from the solar disk center to have minimal projection effects (Falconer, D. A. et al. 2016, ApJL, 833, L31). This program is designed for quiet Sun or on-disk coronal hole targets.

Previous HOPs:
HOP 339. (Data from that HOP were used in Hanaoka et al. 2018, ApJ, 860, 142.)

Additional remarks:
This program will be ran upon request. (The first time is expected to be during
Sanjiv Tiwari’s next turn as SOT CO in late November 2020.) The primary required observations are those from SOT, IRIS, and XRT. EIS observations are optional, but request that they be included if telemetry and planning priorities allow.