HOP 0407

abstract of observational proposal

Main Objective: Complementary spectroscopy of the transition region and corona with SPICE, EIS and IRIS (Quiet Sun + AR as ToO).

Scientific Justification: We would like to take the opportunity of the science observations that SPICE on Solar Orbiter will make during the window of November 16-21 2020 to propose the most extensive spectroscopic coverage currently achievable of the upper solar atmosphere, by combining all 3 instruments.

We propose two types of observations:

1) comparing spectroscopic analysis with similar / complementary lines between the instruments to cover the transition region and corona with SPICE, EIS and IRIS of the quiet Sun, at center disk.

2) comparing spectroscopic analysis with similar / complementary lines between the instruments to analyse an Active Region or a Coronal Hole, would the opportunity arise, as well as providing a follow-up of these targets longer than usual by combining all three instruments.

Due to the available telemetry during the cruise phase of Solar Orbiter (SolO), a window of opportunity for scientific observations has been made available during SolO Short-Term Planning 122 (covering the period of 16-21 November 2020). This is the first time SPICE will make scientific observations following the successful commissioning campaign following the launch in Spring 2020. During this time, Solar Orbiter will be situated at ~0.92 AU and will provide an opportunity to proceed to spectroscopic observations of the disk center with SPICE. Due to the position of the spacecraft (120 degrees away from the Sun-Earth line), co-temporal observations will not be possible. However, observations from EIS and IRIS in the days prior to the beginning of the SPICE observation window will provide an opportunity to cover the Quiet Sun with an extensive spectroscopy coverage. Furthermore, would an active region or a coronal hole appear at anytime in the days prior to the SPICE observations, we request dedicated observations of these structures. This would provide a spectroscopic follow-up of these structures for longer than is usually available with instruments on the Sun-Earth line.

request to EIS

Quiet Sun
Pointing: disk center observation from Hinode point of view. EIS observations should aim to have a similar FOV as SPICE (but from 1 au): 552"x607".

-Regular monitoring with Large_CH_Map (ID 453, covers region 180” x 512” in 65 mins)
Run every 4 hours.

-Regular monitoring with Large_CH_Map (ID 453, covers region 180” x 512” in 65 mins)
Mosaic of 6 scans (3 in x, 2 in y) to have a total region of at least 552"x607", in 6.5hours.
Run once on the 8th of November, 11th, and 13th

-Spectral atlas, Atlas_60 (ID 404, covers 120”x160” in 65mins)
Run every 4 hours

Active region
-Regular monitoring (ID 569, HPW021_VEL_260x512v2, ST_ID: 569, FOV: 260"x512", Exp.: 40s, Dur.: 65mn)
Run every 4 hours

-Spectral atlas, Atlas_60 (ID 404, ST_ID: 404, FOV: 120"x160", Exp.: 60s Dur.:65mn)
Run once per day

-Large format raster, DHB006 (ID 491, 490” x 512” Dur: 68 mins)
Run once per day

Coronal Hole
-Regular monitoring with HOP81_new_study (ID 482, covers region 320” x 384” in 73 mins)
Run every 4 hours.

-Spectral atlas, Atlas_120 (ID 405, covers 120”x160” in 128 mins)
Run once per day.

other participating instruments

Submitted to the IRIS team.

IRIS rasters should have a similar SPICE FOV (within the constraints).
Slit-jaw camera for dynamics in the low atmosphere

-Need for solar rotation compensation
-QS: disk center from IRIS point of view.

Example of studies with IRIS:
3620108077
Very large dense 320-step raster 105.3x175 320s Deep x 8 Spatial x 2
| 2937.36 | 2051.85 | 0.48 | 9.2+/-0.1 | 2937+/-0 | 36.7+/-0.0 | 36.7+/-0.0 | 36.7+/-0.0 | 36.7+/-0.0

Example of dynamic study:
3620600849
Very large sparse 32-step raster 31x175 32s Si IV Mg II h/k Mg II | 65.37 | 115.91 | 1.20 | 2.0+/-0.1 | 65.4+/-0.0 | 0.0+/-0.0 | 16.3+/-0.0 | 16.3+/-0.0 | 16.3+/-0.0

Since IRIS will be in eclipse season, alternate between orbits with scans and orbits with dynamics programs.

remarks

Dates:
Quiet Sun observations
The center disk, quiet sun observations should start on the 8th of November up to the 14th of November.

Explanation: A start on the 8th of November, so 8 days before the beginning of the observation windows for SPICE, would allow us to observe the same region that will appear in the SPICE FOV. Since SPICE will observe for 6 consecutive days, this will provide the same length of observations as SPICE.
We also request 6 consecutive days of observations so as to cover the same observation cadence as SPICE.

Active region or Coronal Hole observations (this is a ToO: if there are none, the following is not needed)

In the event of an Active Region (AR) and/or a Coronal Hole (CH) appearing anytime between the 1st of November and the 8th of November on the east limb of the Sun, we request a ToO daily observation. Follow the ToO up to the west limb.
Explanation: This window of "appearance" is because if these structures are already present on the 1st of November or only appear after the 8th of November, solar rotation will imply that these targets will be missed during the SPICE observation window.

We suggest 13 consecutive days to follow the ToO from limb to limb.

Time window: 15 days maximum (presence of a ToO). 7 days minimun

Target(s) of interes:
For the Quiet Sun:
Target of interest: quiet sun. It matters that this is on-disk.

Explanation: SPICE FOV will be at disk-center. SPICE maximum field of view will be 10'x11'.

For an AR and/or CH:
Target of Opportunity if available: Active region and/or Coronal hole. Follow up from limb to limb.