14476( 8) - 18-Aug-2016 13:45:58 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14476 Version: 8 Check-in Time: 18-Aug-2016 13:45:58 STScI Edit Number: 4 Title A collision reversal in HD 5980 ------------------------------------------------------------------------------------ Type Cycle GO 24 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Yael Naze Universite de Liege Y CoI: Dr. D. John Hillier University of Pittsburgh N CoI: Dr. Gloria Koenigsberger Universidad Nacional Autonoma de Mexico Y (UNAM) CoI: Dr. Julian M. Pittard University of Leeds N CoI: Dr. Michael F. Corcoran Universities Space Research Association N CoI: Dr. Gregor Rauw Universite de Liege N ------------------------------------------------------------------------------------ Abstract HD 5980 provides a unique laboratory for studying the properties of wind-wind collisions. It contains one of only two binary systems having a WR-star in orbit with a LBV. The latter star has been observed to undergo major changes in its wind structure over the past 35 years, implying changes in the geometry and emitting conditions of the wind-wind collision region. Ten years ago, when the LBV wind was very strong, XMM observations revealed X-ray emission consistent with the shock cone wrapping around the WR component. Since then, the wind strength has significantly declined, implying that the collision shock cone may be inverting its orientation. The objective of this proposal is to obtain X-ray coverage of this never before observed phenomenon. We also request HST/STIS observations to determine the wind velocity of the WR-star. All recent HST observations of this system have been performed at the opposite orbital phase, when the LBV occults the WR. The WR wind speed is required for the study of the WWC region. We propose to observe HD 5980 in the 1170 - 1730 A spectral interval with STIS using the FUV- MAMA detector with the E140M grating, plus 3 short exposures with the CCD in order to complete the wavelength coverage out to 10000 A. These observations all fit into 2 orbits. ------------------------------------------------------------------------------------ Observations Description ------------------------ We propose to observe HD 5980 in the 1170 - 1730 A spectral interval with STIS using the FUV- MAMA detector, the E140M grating and the 0.2x0.2 slit. To estimate the exposure times we used our most recent HST spectra obtained in 2013. The Exposure Time Calculator indicates that we will require an exposure of 4600 seconds to achieve S/N~50 per resolution element at 1300 A and S/N>20 in the entire spectral range. The actual exposure time entered into the Orbit Planner is 4597 seconds, split into two exposures, the first of 2569 seconds during the first orbit and the second of 2028 seconds in the second orbit. We are also requesting 3 exposures using the CCD detector and the G230BL, G430L and G750L gratings. This will provide a full spectral energy distribution for the CMFGEN model fits. The requested exposure times are 300 s, 60 s and 60 s, respectively, which will assure S/N~100. The total exposure time+overheads for the CCD spectra is less than 25 min, asuming a 5 min overhead per CCD exposure 14476( 8) - 18-Aug-2016 13:45:58 - [ 2] (HST Primer sec. 6.4.3). The CCD spectra will be obtained during the second orbit. The mixture of MAMA and CCD observations in the same orbit is justified by the short exposure time required for the CCD spectra (HST Primer sec. 6.2.2). We require that the observation be scheduled to coincide with the eclipse of Star A by Star B, which occurs at orbital phase phase=0.36. The orbital period is 19.2654 days, and the initial epoch for the calculation of the eclipse phase is T0 =JD 2443158.707. The optimum results will be for an observation performed within +/-0.01 in phase of the eclipse date. This gives a tolerance of +/-0.2 days. ------------------------------------------------------------------------------------ 14476( 8) - 18-Aug-2016 13:45:58 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD-5980 STAR, EMISSION LINE RA=00H59M26.5687S, J2000 V = 11.31 STAR, LUMINOUS BLUE DEC=-72D09'53.91" VARIABLE, WIND, WOLF RAYET - WN Reference Frame: ICRS Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. ------------------------------------------------------------------------------------------------------------------------------------ 14476( 8) - 18-Aug-2016 13:45:58 - [ 4] Visit: 01 Visit Requirements: BETWEEN 2016.265:11:00:00 AND 2016.265:23:59:59; Period 19.2654 D AND ZERO-PHASE HJD2456991.264 On Hold Comments: Additional Comments: Required to be scheduled for orbital phase 0.36 +/-0.01; Initial epoch T0 =JD 2443158.707 and Period P=19.2654d 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-5980 STIS/CCD ACQ F28X50LP MIRROR 1 0.6 S (0.6 PHASE 0.345 TO 0.37 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 HD-5980 STIS/FUV ACCUM 0.2X0.2 E140M 1425 1 2837 S -MAMA (2837 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 HD-5980 STIS/FUV ACCUM 0.2X0.2 E140M 1425 1 2028 S -MAMA (2028 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 HD-5980 STIS/CCD ACCUM 52X0.2 G230LB 2375 1 300 S (300 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 HD-5980 STIS/CCD ACCUM 52X0.2 G430L 4300 1 60 S (60 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 HD-5980 STIS/CCD ACCUM 52X0.2 G750L 7751 1 60 S (60 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 CCDFLAT STIS/CCD ACCUM 0.3X0.09 G750L 7751 2 0.1 S (0.2 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-5980 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A HD-5980 2 STIS/FUV ACCUM 0.2X0.2 E140M 1425 none none none none 1 N/A -MAMA HD-5980 3 STIS/FUV ACCUM 0.2X0.2 E140M 1425 none none none none 2 N/A -MAMA HD-5980 4 STIS/CCD ACCUM 52X0.2 G230LB 2375 none none none 1 2 N/A HD-5980 4 STIS/CCD ACCUM 52X0.2 G230LB 2375 none none none 2 2 N/A HD-5980 5 STIS/CCD ACCUM 52X0.2 G430L 4300 none none none 1 2 N/A HD-5980 5 STIS/CCD ACCUM 52X0.2 G430L 4300 none none none 2 2 N/A HD-5980 6 STIS/CCD ACCUM 52X0.2 G750L 7751 none none none 1 2 N/A HD-5980 6 STIS/CCD ACCUM 52X0.2 G750L 7751 none none none 2 2 N/A CCDFLAT 7 STIS/CCD ACCUM 0.3X0.09 G750L 7751 none none 1 none 2 N/A CCDFLAT 7 STIS/CCD ACCUM 0.3X0.09 G750L 7751 none none 2 none 2 N/A 14476( 8) - 18-Aug-2016 13:45:58 - [ 5] Summary Form for Proposal 14476 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 0.2X0.2, 0.3X0.09, 52X0.2, F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD, STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 2016.265:11:00:00 AND 2016.265:23:59:59, PHASE 0.345 TO 0.37, Period 19.2654 D AND ZERO-PHASE HJD2456991.264 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements E140M, G230LB, G430L, G750L, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names CCDFLAT, HD-5980 ------------------------------------------------------------------------------------------------------------------------------------