13734( 5) - 24-Oct-2014 13:15:39 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 13734 Version: 5 Check-in Time: 24-Oct-2014 13:15:39 STScI Edit Number: 2 Title Probing the extreme wind confinement of the most magnetic O star with COS spectroscopy ------------------------------------------------------------------------------------ Type Cycle GO 22 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Veronique Petit Florida Institute of Technology Y CoI: Dr. Jon O. Sundqvist Universitats-Sternwarte Munchen N CoI: Dr. Alexander W. Fullerton Space Telescope Science Institute N CoI: Dr. Nolan R. Walborn Space Telescope Science Institute N CoI: Dr. Gregg A. Wade Royal Military College of Canada N CoI: Dr. David Cohen Swarthmore College N CoI: Dr. Asif ud-Doula The Pennsylvania State University N CoI: Dr. Jesus Maiz Apellaniz Instituto de Astrofisica de Andalucia N (IAA) CoI: Dr. Jason Grunhut European Southern Observatory - Germany N CoI: Dr. Rodolfo H. Barba Universidad de La Serena N ------------------------------------------------------------------------------------ Abstract We propose to obtain phase-resolved UV spectroscopy of the recently discovered magnetic O star NGC 1624-2, which has the strongest magnetic field ever detected in a O-star, by an order of magnitude. We will use the strength and variability of the UV resonance line profiles to diagnose the density, velocity, and ionization structure of NGC 1624-2's enormous magnetosphere that results from entrapment of its stellar wind by its strong, nearly dipolar magnetic field. With this gigantic magnetosphere, NGC 1624-2 represents a new regime of extreme wind confinement that will constrain models of magnetized winds and their surface mass flux properties. A detailed understanding of such winds is necessary to study the rotational braking history of magnetic O-stars, which can shed new light on the fundamental origin of magnetism in massive, hot stars. ------------------------------------------------------------------------------------ Observations Description ------------------------ Our program requires time-critical observations of NGC 1624-2 at two rotational phases, as described below. For each of these observations, we aim to investigate important photospheric, wind, and magnetospheric features such as N V 1239, 1243 A, Si IV 1393, 1403 A, C IV 1548, 1550 AA, N IV 1718 A. NGC 1624-2, with V=11.8, E(B-V)=0.9, will therefore be optimally observed at the COS medium resolution with the G130M (settings 1291, 1327 A) and G160M (1577, 1623 A) gratings for the maximum available, uninterrupted wavelength coverage of 1134 - 1798 A. Two orbits in each of the two visits at high and low states will be required. The coordinates of the target are precise enough to use the ACQ-image. The BOA aperture is used for the acquisition. An exposure of 86 seconds is enough to 13734( 5) - 24-Oct-2014 13:15:39 - [ 2] reach the recommanded SNR of 60. The ephemeris for NGC 1624-2 is JD = 245 5967.0 (+-10) + 157.99 (+-0.94) x E (Wade et al. 2012). A tolerance of +-0.05 cycles around the desired phases leads to periodic observational windows of 2 weeks that are consistent with these constraints. ------------------------------------------------------------------------------------ 13734( 5) - 24-Oct-2014 13:15:39 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC1624-2 STAR, OF RA=04H40M37.2660S +/- 0.2", J2000 V = 11.77 DEC=+50D27'40.96" +/- 0.2" Reference Frame: ICRS Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 13734( 5) - 24-Oct-2014 13:15:39 - [ 4] Visit: 01 Visit Requirements: Period 157.99 D AND ZERO-PHASE HJD2455967.0 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 NGC1624-2 COS/NUV ACQ/IMA BOA MIRRORA 1 86 S (86 PHASE 0.95 TO 0.05 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC1624-2 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=1124, FP-POS=ALL 1 200 S G see below (848 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC1624-2 COS/FUV TIME-TA PSA G130M 1327 BUFFER-TIME=992, FP-POS=ALL 1 200 S G see below (844 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC1624-2 COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=922, FP-POS=ALL 1 200 S G see below (1084 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC1624-2 COS/FUV TIME-TA PSA G160M 1623 FP-POS=ALL, BUFFER-TIME=1012 1 200 S G see below (1080 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC1624-2 1 COS/NUV ACQ/IMA BOA MIRRORA none none none none 1 N/A GE NGC1624-2 2 COS/FUV TIME-TA PSA G130M 1291 none none none 1 1 212.0 S G NGC1624-2 2 COS/FUV TIME-TA PSA G130M 1291 none none none 2 1 212.0 S G NGC1624-2 2 COS/FUV TIME-TA PSA G130M 1291 none none none 3 1 212.0 S G NGC1624-2 2 COS/FUV TIME-TA PSA G130M 1291 none none none 4 1 212.0 S G NGC1624-2 3 COS/FUV TIME-TA PSA G130M 1327 none none none 1 1 211.0 S G NGC1624-2 3 COS/FUV TIME-TA PSA G130M 1327 none none none 2 1 211.0 S G NGC1624-2 3 COS/FUV TIME-TA PSA G130M 1327 none none none 3 1 211.0 S G 13734( 5) - 24-Oct-2014 13:15:39 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC1624-2 3 COS/FUV TIME-TA PSA G130M 1327 none none none 4 1 211.0 S G NGC1624-2 4 COS/FUV TIME-TA PSA G160M 1577 none none none 1 2 271.0 S G NGC1624-2 4 COS/FUV TIME-TA PSA G160M 1577 none none none 2 2 271.0 S G NGC1624-2 4 COS/FUV TIME-TA PSA G160M 1577 none none none 3 2 271.0 S G NGC1624-2 4 COS/FUV TIME-TA PSA G160M 1577 none none none 4 2 271.0 S G NGC1624-2 5 COS/FUV TIME-TA PSA G160M 1623 none none none 1 2 270.0 S G NGC1624-2 5 COS/FUV TIME-TA PSA G160M 1623 none none none 2 2 270.0 S G NGC1624-2 5 COS/FUV TIME-TA PSA G160M 1623 none none none 3 2 270.0 S G NGC1624-2 5 COS/FUV TIME-TA PSA G160M 1623 none none none 4 2 270.0 S G 13734( 5) - 24-Oct-2014 13:15:39 - [ 6] Visit: 02 Visit Requirements: Period 157.99 D AND ZERO-PHASE HJD2455967.0 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 NGC1624-2 COS/NUV ACQ/IMA BOA MIRRORA 1 86 S (86 PHASE 0.45 TO 0.55 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC1624-2 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=1124, FP-POS=ALL 1 120 S G see below (848 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC1624-2 COS/FUV TIME-TA PSA G130M 1327 BUFFER-TIME=992, FP-POS=ALL 1 120 S G see below (844 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC1624-2 COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=922, FP-POS=ALL 1 225 S G see below (1084 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC1624-2 COS/FUV TIME-TA PSA G160M 1623 FP-POS=ALL, BUFFER-TIME=1012 1 225 S G see below (1080 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC1624-2 1 COS/NUV ACQ/IMA BOA MIRRORA none none none none 1 N/A GE NGC1624-2 2 COS/FUV TIME-TA PSA G130M 1291 none none none 1 1 212.0 S G NGC1624-2 2 COS/FUV TIME-TA PSA G130M 1291 none none none 2 1 212.0 S G NGC1624-2 2 COS/FUV TIME-TA PSA G130M 1291 none none none 3 1 212.0 S G NGC1624-2 2 COS/FUV TIME-TA PSA G130M 1291 none none none 4 1 212.0 S G NGC1624-2 3 COS/FUV TIME-TA PSA G130M 1327 none none none 1 1 211.0 S G NGC1624-2 3 COS/FUV TIME-TA PSA G130M 1327 none none none 2 1 211.0 S G NGC1624-2 3 COS/FUV TIME-TA PSA G130M 1327 none none none 3 1 211.0 S G 13734( 5) - 24-Oct-2014 13:15:39 - [ 7] 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 | ------------------------------------------------------------------------------------------------------------------------------------ NGC1624-2 3 COS/FUV TIME-TA PSA G130M 1327 none none none 4 1 211.0 S G NGC1624-2 4 COS/FUV TIME-TA PSA G160M 1577 none none none 1 2 271.0 S G NGC1624-2 4 COS/FUV TIME-TA PSA G160M 1577 none none none 2 2 271.0 S G NGC1624-2 4 COS/FUV TIME-TA PSA G160M 1577 none none none 3 2 271.0 S G NGC1624-2 4 COS/FUV TIME-TA PSA G160M 1577 none none none 4 2 271.0 S G NGC1624-2 5 COS/FUV TIME-TA PSA G160M 1623 none none none 1 2 270.0 S G NGC1624-2 5 COS/FUV TIME-TA PSA G160M 1623 none none none 2 2 270.0 S G NGC1624-2 5 COS/FUV TIME-TA PSA G160M 1623 none none none 3 2 270.0 S G NGC1624-2 5 COS/FUV TIME-TA PSA G160M 1623 none none none 4 2 270.0 S G 13734( 5) - 24-Oct-2014 13:15:39 - [ 8] Summary Form for Proposal 13734 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures BOA, PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=1012, BUFFER-TIME=1124, BUFFER-TIME=922, BUFFER-TIME=992, FP-POS=ALL ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PHASE 0.45 TO 0.55, PHASE 0.95 TO 0.05, Period 157.99 D AND ZERO-PHASE HJD2455967.0 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G130M, G160M, MIRRORA ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC1624-2 ------------------------------------------------------------------------------------------------------------------------------------