16421( 3) - 15-Sep-2020 14:32:54 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 16421 Version: 3 Check-in Time: 15-Sep-2020 14:32:54 STScI Edit Number: 0 Title The Secrets of Stellar Siestas: the Magnetic Grand Minimum Candidate HD 4915 ------------------------------------------------------------------------------------ Type Cycle GO 28 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Steven H. Saar Smithsonian Institution Astrophysical Y Observatory CoI: Dr. Jason T Wright The Pennsylvania State University N CoI: Dr. Jeremy J. Drake Smithsonian Institution Astrophysical N Observatory CoI: Bradford Wargelin Smithsonian Institution Astrophysical N Observatory CoI: Dr. Vinay Kashyap Smithsonian Institution Astrophysical N Observatory ------------------------------------------------------------------------------------ Abstract Magnetic grand minima (MGM) are mysterious episodes when the Sun's magnetic dynamo cycle "takes a siesta" and goes into temporary quiescence. The phenomenon has never been observed in modern times; what was the Sun like then? Recently a star was observed to have a decaying cycle amplitude (in Ca HK), making it a strong candidate for an MGM episode. We propose to study the star with Chandra and HST, to explore magnetic heating throughout its outer atmosphere. Results will be compared with cycle minima and stars with "flat activity" (objects which may be in MGM or have "dead" dynamos) to explore similarities and differences, and reveal what may lie in store for our own Sun in the near future. ------------------------------------------------------------------------------------ Observations Description ------------------------ We desire FUV low resolution (G140L) observation of a bright, low activity star. It has GAIA coordinates, so an ACQ/SEARCH is not needed. It is bright and so target ACQ is in imaging mode with BOA, but UV dim enough that time-tag mode is possible. After target ACQ, the remainder of the time is spent with the science observation for the star. ------------------------------------------------------------------------------------ 16421( 3) - 15-Sep-2020 14:32:54 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD-4915 STAR, G V-IV RA=00H51M11.1196S +/- 0.0304", J2000 V = V = 6.972 DEC=-05D02'23.25" +/- 0.0263" -3.692 Reference Frame: ICRS Extended: NO Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. Coords checked - they are ICRS from simbad (J2000) with proper motion applied to epoch 2015.5 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2015.5 0.01751625238790978 -0.1189489998978388 0.04448 ------------------------------------------------------------------------------------------------------------------------------------ 16421( 3) - 15-Sep-2020 14:32:54 - [ 3] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 HD-4915 COS/NUV ACQ/IMA BOA MIRRORB 1 44 S (44 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 HD-4915 COS/FUV TIME-TA PSA G140L 1280 BUFFER-TIME=17947, FP-POS=ALL 1 927 S G see below (4820 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ HD-4915 1 COS/NUV ACQ/IMA BOA MIRRORB none none none none 1 N/A GE HD-4915 2 COS/FUV TIME-TA PSA G140L 1280 none none none 1 1 1118.0 S G HD-4915 2 COS/FUV TIME-TA PSA G140L 1280 none none none 2 1 1118.0 S G HD-4915 2 COS/FUV TIME-TA PSA G140L 1280 none none none 3 2 1292.0 S G HD-4915 2 COS/FUV TIME-TA PSA G140L 1280 none none none 4 2 1292.0 S G 16421( 3) - 15-Sep-2020 14:32:54 - [ 4] Summary Form for Proposal 16421 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures BOA, PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=17947, FP-POS=ALL ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G140L, MIRRORB ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD-4915 ------------------------------------------------------------------------------------------------------------------------------------