16933( 3) - 05-May-2022 13:15:43 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 16933 Version: 3 Check-in Time: 05-May-2022 13:15:43 STScI Edit Number: 1 Title The Origin and Impact of Flares in M Dwarf Systems ------------------------------------------------------------------------------------ Type Cycle GO/DD 29 ------------------------------------------------------------------------------------ Investigators Contact? PI: Prof. Meredith MacGregor University of Colorado at Boulder Y CoI: Dr. Alycia J. Weinberger Carnegie Institution of Washington N CoI: Kiana Burton University of Colorado at Boulder N CoI: Dr. Steven Cranmer University of Colorado at Boulder N CoI: Dr. Ward Howard University of Colorado at Boulder N CoI: Dr. Nicholas N Law University of North Carolina at Chapel N Hill CoI: Dr. R. O. Parke Loyd Eureka Scientific Inc. N CoI: Prof. Jaymie Matthews University of British Columbia N CoI: Dr. Rachel A. Osten Space Telescope Science Institute N CoI: Dr. Evgenya L. Shkolnik Arizona State University N CoI: Dr. David Wilner Smithsonian Institution Astrophysical N Observatory CoI: Dr. Elisa V Quintana NASA Goddard Space Flight Center N CoI: Dr. Thomas Barclay University of Maryland Baltimore County N CoI: Dr. Allison Youngblood NASA Goddard Space Flight Center N CoI: Dr. John Sebastian Pineda University of Colorado at Boulder N CoI: Andrew Zic Macquarie University N CoI: Dr. Tara Murphy University of Sydney N CoI: Jan Forbrich University of Hertfordshire N CoI: Laura Daniela Vega NASA Goddard Space Flight Center N CoI: Mr. Rishi Paudel University of Maryland Baltimore County N ------------------------------------------------------------------------------------ Abstract M dwarf stars are the most abundant stars in the galaxy and have a high frequency of Earth-sized planets, making them the favored targets of upcoming missions to detect and characterize exoplanets. However, these stars are known to exhibit high levels of activity and flaring, which can deplete a planet's atmosphere of water and ozone over time, raising questions about the habitability of planets around these stars. It is clear that there is still much to be learned about M dwarfs, their activity, and the potential habitability of their planetary systems. Monitoring campaigns with simultaneous observations across a broad range of wavelengths are needed in order to determine how stellar flaring emission correlates across the electromagnetic spectrum. Here, we propose to conduct such a campaign using HST STIS for four nearby M dwarfs, spectral analogues of Proxima Cen spanning a range of ages and activity levels. We have already been awarded observing time with ALMA, Swift, NICER, and ground-based optical facilities that will be executed simultaneously between now and October 2022. These HST DDT observations are the only way to add FUV coverage to this campaign. Recent observations of Proxima Cen suggest that UV and millimeter emission trace each other closely during flares, and this proposed study will show whether this is a universal property of mid-M dwarfs regardless of age. By deriving a scaling relation between millimeter and UV emission, we will have a powerful new 16933( 3) - 05-May-2022 13:15:43 - [ 2] tool to determine the UV environment of stars and their potential to host habitable planets, and be able to capitalize on existing all-sky cosmology surveys at millimeter and radio wavelengths. ------------------------------------------------------------------------------------ Observations Description ------------------------ Monitoring campaigns with simultaneous observations across a broad range of wavelengths are needed in order to determine how stellar flaring emission correlates across the electromagnetic spectrum. This new study will show whether the correlation between millimeter and UV emission is a universal property of mid-M dwarfs regardless of age and activity level. Wolf 359 is a well-known flare star (Robinson et al. 1995) that was the target of a recent campaign with Kepler/K2, Swift, LCOGT, and radio facilities spanning 20 MHz - 3.1 GHz. Using 1 min cadence, more than 800 flares were detected in 80 days (Quintana, priv. comm.). Compared to Proxima Cen, both stars have similar slopes of their flare frequency distributions, but Wolf 359 has significantly more flares at all energies. ALMA and Chandra time were also awarded for Wolf 359. The combination of the HST UV observations with simultaneous monitoring at millimeter, x-ray, and optical wavelengths will definitively show any correlations between flaring emission at these different wavelengths. By observing for 12 orbits, we should detect >7 large flares and many more small flares from Wolf 359 given its 2x higher flare rate than Proxima Cen. MAMA safety: We conservatively take the SIMBAD spectral type of M6 and U-band quiescent magnitude of 16.71. A 10^{-4} probability flare would produce a maximum U-band magnitude increase of -2.8 mag, yielding a peak U-band magnitude of 13.91. With these input values, we find peak line fluxes during a 10 ^{-4} probability flare of 3.1e-13 erg/s/cm^2 (C IV), 1.2e-13 (Si IV), and 3.1e-13 (Ly alpha). When these line fluxes and a 9000 K blackbody associated with the flaring U-band magnitude are run through the ETC, count rate limits for the STIS E140M spectrograph are not violated. Observing plan: HST STIS E140M grating (0.2 x 0.2 arcsec slit, covering 1150 - 1700 Ang), 3 visits of 4 orbits each Target acquisition in the STIS/CCD with the F28x50OII aperture at an exposure time of 10 sec. TIME-TAG mode. ------------------------------------------------------------------------------------ 16933( 3) - 05-May-2022 13:15:43 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 2 WOLF-359 STAR, EMISSION LINE RA=10H56M24.7675S, J2000 V = 13.507 U=16.706 STAR, IRREGULAR DEC=+07D00'9.82" VARIABLE, M V-IV Reference Frame: ICRS Comments: Gaia EDR3 ICRS Ep=2016.0 coordinates pmra = pm(EDR3) / 15. / cos(dec) / 1000. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2016.0 -0.25969309 -2.699215 0.4151794 ------------------------------------------------------------------------------------------------------------------------------------ 16933( 3) - 05-May-2022 13:15:43 - [ 4] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: UV spectra of Wolf 359 JD 2459700.493056 (May 1 at 23:10) is the approximate start of nightime observing at ALMA. See table below. The first 13 minuts of the first orbit are acquisitions, so orbit can start at 23:10 and have the spectra be taken after dark. sunset end of astro twilight airmass 1.5 airmass 2.0 04/26 22:11 23:23 03:47 05/08 22:03 23:18 03:00 05/22 21:55 23:14 02:04 06/03 21:54 23:14 02:15 *last day for 3 hours of dark above airmass 2 06/17 21:53 23:13 00:21 01:20 06/30 21:56 23:16 23:31 00:29 07/10 22:00 23:20 23:49 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 WOLF-359 STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 0.3 S (0.3 S) Comments: STIS ETC using F28x50LP, I=9.507 and Phoenix M dwarf Models M5.5 3000K gives S/N~258 in 0.3 s, saturates at 1.88 s ------------------------------------------------------------------------------------------------------------------------------------ 2 WOLF-359 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=500 1 2271 S -MAMA G (2271 S) Comments: ETC says S/N=0 on continuum U-band, but that's not really relevant. ------------------------------------------------------------------------------------------------------------------------------------ 3 WOLF-359 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=500 1 2723 S -MAMA G (2723 S) Comments: ETC says S/N=0 on continuum U-band, but that's not really relevant. ------------------------------------------------------------------------------------------------------------------------------------ 4 WOLF-359 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=500 1 2723 S -MAMA G (2723 S) Comments: ETC says S/N=0 on continuum U-band, but that's not really relevant. ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ WOLF-359 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A WOLF-359 2 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 1 N/A -MAMA G 16933( 3) - 05-May-2022 13:15:43 - [ 5] 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 | ------------------------------------------------------------------------------------------------------------------------------------ WOLF-359 3 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 2 N/A -MAMA G WOLF-359 4 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 3 N/A -MAMA G 16933( 3) - 05-May-2022 13:15:43 - [ 6] Visit: 02 Visit Requirements: On Hold Comments: Additional Comments: UV spectra of Wolf 359 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 WOLF-359 STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 0.3 S (0.3 S) Comments: STIS ETC using F28x50LP, I=9.507 and Phoenix M dwarf Models M5.5 3000K gives S/N~258 in 0.3 s, saturates at 1.88 s ------------------------------------------------------------------------------------------------------------------------------------ 2 WOLF-359 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=500 1 2271 S -MAMA G (2271 S) Comments: ETC says S/N=0 on continuum U-band, but that's not really relevant. ------------------------------------------------------------------------------------------------------------------------------------ 3 WOLF-359 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=500 1 2723 S -MAMA G (2723 S) Comments: ETC says S/N=0 on continuum U-band, but that's not really relevant. ------------------------------------------------------------------------------------------------------------------------------------ 4 WOLF-359 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=500 1 2723 S -MAMA G (2723 S) Comments: ETC says S/N=0 on continuum U-band, but that's not really relevant. ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ WOLF-359 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A WOLF-359 2 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 1 N/A -MAMA G WOLF-359 3 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 2 N/A -MAMA G WOLF-359 4 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 3 N/A -MAMA G 16933( 3) - 05-May-2022 13:15:43 - [ 7] Visit: 03 Visit Requirements: On Hold Comments: Additional Comments: UV spectra of Wolf 359 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 WOLF-359 STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 0.3 S (0.3 S) Comments: STIS ETC using F28x50LP, I=9.507 and Phoenix M dwarf Models M5.5 3000K gives S/N~258 in 0.3 s, saturates at 1.88 s ------------------------------------------------------------------------------------------------------------------------------------ 2 WOLF-359 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=500 1 2271 S -MAMA G (2271 S) Comments: ETC says S/N=0 on continuum U-band, but that's not really relevant. ------------------------------------------------------------------------------------------------------------------------------------ 3 WOLF-359 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=500 1 2723 S -MAMA G (2723 S) Comments: ETC says S/N=0 on continuum U-band, but that's not really relevant. ------------------------------------------------------------------------------------------------------------------------------------ 4 WOLF-359 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=500 1 2723 S -MAMA G (2723 S) Comments: ETC says S/N=0 on continuum U-band, but that's not really relevant. ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ WOLF-359 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A WOLF-359 2 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 1 N/A -MAMA G WOLF-359 3 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 2 N/A -MAMA G WOLF-359 4 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 3 N/A -MAMA G 16933( 3) - 05-May-2022 13:15:43 - [ 8] Summary Form for Proposal 16933 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 0.2X0.2, F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD, STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT, BUFFER-TIME=500 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements E140M, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names WOLF-359 ------------------------------------------------------------------------------------------------------------------------------------