9231( 6) - 01/20/03 09:44 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9231 Version: 6 Check-in Date: 20-Jan-2003 09:43:31 1.Proposal Title: VV Cephei: The Egress from Chromospheric Eclipse ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 10 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Philip Bennett University of Colorado at Boulder CoI: Dr. Wendy Hagen Bauer Wellesley College N CoI: Dr. Graham Harper University of Colorado N CoI: Dr. Alexander Brown University of Colorado N CoI: Dr. Stephenson Yang University of Victoria N CoI: Dr. Edward Guinan Villanova University N CoI: Dr. Robert Stencel University of Denver N CoI: Dr. Jeffrey Linsky JILA N ------------------------------------------------------------------------------------ 5. Abstract We propose to obtain STIS and FGS1R observations of the long- period (20.3 yrs) eclipsing binary VV Cephei (M2 Iab + B0) as it continues to emerge from chromospheric eclipse. In Cycle 8, we obtained observations at two visits to VV Cep, as well as comparison spectra of the similar, but less interacting (and non- eclipsing) binaries KQ Pup and HR 8164. For Cycles 9 & 10, we continue our spectroscopic monitoring of the egress from eclipse by proposing to obtain two additional visits each cycle. This project is a continuation of the Cycle 7 program ``The 1997/98 Eclipse of VV Cephei'' (GO-7269), which used the STIS high resolution echelle modes to probe the chromosphere of the M supergiant primary. This is done by observing the absorption spectrum of the primary's chromosphere, which appears superimposed upon the companion's early-type continuum. Repeated monitoring of the evolution of the chromospheric absorption spectrum during egress from total eclipse permits the construction of an empirical model of the chromosphere and wind of the M2 supergiant. VV Cep is unique among eclipsing binaries in being sufficiently bright for high resolution spectroscopy. The proposed STIS observations will probe the wind acceleration region; obtaining empirical information here is of crucial importance in understanding the nature of energy and momentum deposition in these cool winds. In addition, we will observe VV Cep with the newly impleme obtain relative orbit information, and accurate stellar masses. ------------------------------------------------------------------------------------ 9231( 6) - 01/20/03 09:44 - [ 2] Observations Description ------------------------ The Cycle 8 STIS and FGS1R observations began upon completion of the GO program 7269 in June 1999. We obtained two visits to VV Cep, plus one visit of KQ Pup & HR 8164 each, in Cycle 8. We propose to obtain two visits of our primary target VV Cep in each of Cycles 9 & 10, to supplement the extensive data set obtained by GO-7269 & 8257. These observations will use the STIS medium and high resolution echelle modes. In particular, we will use several tilts of E230H spanning 2120-3150 Angstrom, two E140H tilts spanning 1240-1630 Angstrom, and the E140M and short wavelength primary setting of E230M to complete the spectral coverage. We will also obtain G230LB and G430L low resolution spectra through a photometric aperture at each visit. These absolute fluxes in combination with the observed eclipse durations, will be used to determine stellar radii (see Bennett et al.\ 1996 for detailed method). All of these observations will be scheduled as CVZ visits, greatly enhancing the effi observing program. We plan to obtain a S/N ~ 30 in the continuum. To estimate the exposure times out of eclipse we used a combination of IUE spectra LWP21568 and SWP42943 of VV Cep input to the STIS exposure simulator. Maximum count rates, both the local and global, are well below the MAMA bright limits in the brightest IUE spectrum. Typical continuum flux levels are 4.0d-12 ergs cm^-2 s^-1 AA^-1. The largest flux occurs in the Mg II emission lines near periastron (far from eclipse) at about 1.0d-11 ergs cm^-2 s^-1 AA^-1. The fluxes of the comparison stars, KQ Pup and HR 8164, although brighter, are still below the MAMA bright limits. The proposed STIS observations will sample the absorbing column density along the B star line of sight as its sweeps through the chromosphere and wind of the M supergiant primary. The diagnostics of interest include the resonance and low-lying lines of C I--II, N I, O I, Mg I--II, Al I- -III, Si I--III, and a large number o Fe III. In particular, lines of Fe I RMT multiplets 9, 11, 30, and UV 1, 2, 5--9, 11, 14, 44, 46, 52, 87, 156 and of Fe II multiplets Fe II UV 1, 2 3, 32, 33, 35, 36, 60--64, 78, 117, 144--147, 158-- 161, 164, 171--178, 195--205, etc. have measured oscillator strengths (Fuhr, Martin, & Wiese 1988) and will be observed at high resolution (R ~ 110, 000). There are also a large number of lines of Ni II, Cr II, and several Si I, Mn II and Ti II lines with measured oscillator strengths that will be observed at high resolution. All of the Fe I--II and Ni II lines come from low-lying even parity levels from which further radiative decays are strongly forbidden. We will use the superb spectral resolution and S/N of the STIS echelle modes to separate the narrow chromospheric and wind lines from the broad, variable, ``shell'' absorption features. We also obtained two FGS1R observations during the Cycle 8 VV Cep visits, as well as FGS observatio of the two comparison stars (KQ Pup & HR 8164). We propose to obtain one additional FGS1R observation of our primary target VV Cep in each of Cycles 9 & 10. These observations will be performed in TRANSFER mode, which will allow spatial resolution of the ``visual orbit'' of VV Cep, using a F5ND neutral density filter because of the brightness of the sources. In combination with the known spectroscopic orbit, stellar masses can be determined. The use of additional constraints provided by the UV fluxes, and eclipse durations allows the stellar radii to be determined. The proposed solution procedure is identical to that followed by the PI for Zeta Aur (Bennett et al.\ 1996). Since the additional time required to time required obtain the FGS scans (acquire new guide stars, obtain scans, and overhead) is only about 25 mins., these observations can easily be fitted into the end of one of the CVZ visits. Therefore, the FGS observations yield a substantial science return at very li main drawback is the need to obtain special FGS1R calibration observations, of standard single stars matching the spectral types of the VV Cep components (M2 Iab and B0), at a time near the science observations because of slow changes in the shape of the FGS reference S-curves over time. In any case, there is no suitable M supergiant reference S- 9231( 6) - 01/20/03 09:44 - [ 3] curve in the FGS transfer mode color library. The calibrators we observed in Cycle 8 were Mu Cep (M2 Ia) and Lambda Lep = HD 34816 (B0.5 IV). The latter is an FGS3 reference library target, but no M supergiant is listed in the calibration library. Although we tentatively allocated 2 orbits in Cycles 9 & 10 for additional FGS calibrations, the stability of FGS1R over time appears to be excellent. Therefore, we feel it more appropriate to use these 2 orbits to obtain additional science observations of our primary target VV Cep, as reflected in the Cycle 9 Phase II submission, and use our Cycle 8 ob 10. Real Time Justification ----------------------- This program is a continuation of GO programs 7269, 8257, and 8779 which monitored the emergence of the eclipsing binary VV Cephei from total eclipse in order to construct an empirical model of the chromosphere of the M2 Iab primary star. All of the observations of VV Cep will be scheduled as CVZ visits. VV Cep lies in the heart of the CVZ, and has CVZ windows available every HST precession period of 56 days. We also specify ORIENT angle constraints to ensure that the binary axis lies at approximately 45 degrees to the FGS X, Y axes; in practice this restricts the scheduable times to approximately every other CVZ visit. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9231( 6) - 01/20/03 09:44 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD208816 STAR, COMPOSITE RA=21H 56M 39.14S +/- 0.00049", J2000 V = - V = 4.91+/-0.03 SPECTRAL TYPE, M III-I, DEC=63D 37' 32.0" +/- 0.00042" 18.7 TYPE=M2IAB+B EMISSION LINE STAR F-CONT(2800)=6+/-2e-12 F-CONT(1400)=4+/-2e-12 F-LINE(2796)=2.5+/-1.0e-11 W-LINE(2796)=2.9 E(B-V) = 0.4+/-0.1 B-V = +1.77 Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE Comments: Coordinates are from the Hipparcos/Tycho Catalog (VV- Cep= HIP108317). Uneclipsed fluxes are from IUE. STIS UV exposure calculations based on IUE images SWP42943 and LWP21568. Uneclipsed continuum flux varies by +/- 50% in the NUV and +/- 100% in the FUV. Optical exposures assume a Kurucz M2I model. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) B1991.25 -0.00005 -0.00382 0.00039 9231( 6) - 01/20/03 09:44 - [ 5] Visit: 01 Visit Priority: Visit Requirements: CVZ BETWEEN 02-Aug-2001 AND 14-Aug-2001 On Hold Comments: Additional Comments: Time critical observation of eclipsing binary VV Cep. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 HD208816 STIS/C ACQ F25ND5 MIRROR 1 4 S SEQ 10-130 NON-INT CD ------------------------------------------------------------------------------------------------------------------------------------ 20 HD208816 STIS/C ACCUM 52X0.5 G230LB 2375 CR-SPLIT=2,GAIN=1,BINAXIS1=1, 1 20 S CD BINAXIS2=1 ------------------------------------------------------------------------------------------------------------------------------------ 30 HD208816 STIS/C ACCUM 52X0.5 G430L 4300 CR-SPLIT=2,GAIN=1,BINAXIS1=1, 1 0.4 S CD BINAXIS2=1 ------------------------------------------------------------------------------------------------------------------------------------ 40 HD208816 STIS/C ACCUM 52X0.5 G430L 4300 CR-SPLIT=2,GAIN=1,BINAXIS1=1, 1 4 S CD BINAXIS2=1 ------------------------------------------------------------------------------------------------------------------------------------ 50 HD208816 STIS/C ACQ/PEA 0.2X0.2 G430L 4300 1 0.2 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 60 HD208816 STIS/N ACCUM 0.2X0.2 E230H 3012 BINAXIS1=NO,BINAXIS2=NO 1 11 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 70 HD208816 STIS/N ACCUM 0.2X0.2 E230H 2862 BINAXIS2=NO,BINAXIS1=NO 1 9 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 80 HD208816 STIS/N ACCUM 0.2X0.2 E230H 2713 BINAXIS1=NO,BINAXIS2=NO 1 8 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 90 HD208816 STIS/N ACCUM 0.2X0.2 E230H 2563 BINAXIS1=NO,BINAXIS2=NO 1 9 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 100 HD208816 STIS/N ACCUM 0.2X0.2 E230H 2413 BINAXIS1=NO,BINAXIS2=NO 1 11 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 110 HD208816 STIS/N ACCUM 0.2X0.2 E230H 2263 BINAXIS1=NO,BINAXIS2=NO 2 8 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 120 HD208816 STIS/N ACCUM 0.2X0.2 E230M 1978 BINAXIS1=NO,BINAXIS2=NO 2 500 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9231( 6) - 01/20/03 09:44 - [ 6] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 130 HD208816 STIS/F ACCUM 0.2X0.2 E140M 1425 BINAXIS1=NO,BINAXIS2=NO 2 10 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9231( 6) - 01/20/03 09:44 - [ 7] Visit: 02 Visit Priority: Visit Requirements: CVZ ORIENT 357D TO 27D ORIENT 177D TO 207D BETWEEN 26-Aug-2002 AND 07-Sep- 2002 On Hold Comments: Additional Comments: Time critical observation of eclipsing binary VV Cep. ORIENT requirement is to place binary axis (P.A. near 147D) at 45D or 135D to FGS1R X and Y axes for optimal use of TRANSFER mode. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 HD208816 STIS/C ACQ F25ND5 MIRROR 1 4 S SEQ 10-150 NON-INT CD ------------------------------------------------------------------------------------------------------------------------------------ 20 HD208816 STIS/C ACCUM 52X0.5 G230LB 2375 CR-SPLIT=2,GAIN=1,BINAXIS1=1, 1 20 S CD BINAXIS2=1 ------------------------------------------------------------------------------------------------------------------------------------ 30 HD208816 STIS/C ACCUM 52X0.5 G430L 4300 CR-SPLIT=2,GAIN=1,BINAXIS1=1, 1 0.4 S CD BINAXIS2=1 ------------------------------------------------------------------------------------------------------------------------------------ 40 HD208816 STIS/C ACCUM 52X0.5 G430L 4300 CR-SPLIT=2,GAIN=1,BINAXIS1=1, 1 4 S CD BINAXIS2=1 ------------------------------------------------------------------------------------------------------------------------------------ 50 HD208816 STIS/C ACQ/PEA 0.2X0.2 G430L 4300 1 0.2 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 60 HD208816 STIS/N ACCUM 0.2X0.2 E230H 3012 BINAXIS1=NO,BINAXIS2=NO 1 9 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 70 HD208816 STIS/N ACCUM 0.2X0.2 E230H 2862 BINAXIS2=NO,BINAXIS1=NO 1 7 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 80 HD208816 STIS/N ACCUM 0.2X0.2 E230H 2713 BINAXIS1=NO,BINAXIS2=NO 1 7 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 90 HD208816 STIS/N ACCUM 0.2X0.2 E230H 2563 BINAXIS1=NO,BINAXIS2=NO 1 8 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 100 HD208816 STIS/N ACCUM 0.2X0.2 E230H 2413 BINAXIS1=NO,BINAXIS2=NO 1 10 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 110 HD208816 STIS/N ACCUM 0.2X0.2 E230H 2263 BINAXIS1=NO,BINAXIS2=NO 1 750 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 120 HD208816 STIS/N ACCUM 0.2X0.2 E230M 1978 BINAXIS1=NO,BINAXIS2=NO 2 8 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9231( 6) - 01/20/03 09:44 - [ 8] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 130 HD208816 STIS/F ACCUM 0.2X0.2 E140H 1526 BINAXIS1=NO,BINAXIS2=NO 2 13 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 140 HD208816 STIS/F ACCUM 0.2X0.2 E140H 1343 BINAXIS1=NO,BINAXIS2=NO 2 10 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 150 HD208816 STIS/F ACCUM 0.2X0.2 E140M 1425 BINAXIS1=NO,BINAXIS2=NO 2 10 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 160 HD208816 FGS TRANS 1 F5ND STEP-SIZE=0.6,SCANS=24 1 1500 S NO SPLIT GS ACQ SCENARIO SINGLE ------------------------------------------------------------------------------------------------------------------------------------ 9231( 6) - 01/20/03 09:44 - [ 9] Visit: 12 Visit Priority: Visit Requirements: CVZ BETWEEN 01-Sep-2003 AND 01-Jan-2004 On Hold Comments: Additional Comments: Time critical observation of eclipsing binary VV Cep. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 HD208816 STIS/C ACQ F25ND5 MIRROR 1 4 S SEQ 10-130 NON-INT CD ------------------------------------------------------------------------------------------------------------------------------------ 20 HD208816 STIS/C ACCUM 52X0.5 G230LB 2375 CR-SPLIT=2,GAIN=1,BINAXIS1=1, 1 20 S CD BINAXIS2=1 ------------------------------------------------------------------------------------------------------------------------------------ 30 HD208816 STIS/C ACCUM 52X0.5 G430L 4300 CR-SPLIT=2,GAIN=1,BINAXIS1=1, 1 0.4 S CD BINAXIS2=1 ------------------------------------------------------------------------------------------------------------------------------------ 40 HD208816 STIS/C ACCUM 52X0.5 G430L 4300 CR-SPLIT=2,GAIN=1,BINAXIS1=1, 1 4 S CD BINAXIS2=1 ------------------------------------------------------------------------------------------------------------------------------------ 50 HD208816 STIS/C ACQ/PEA 0.2X0.2 G430L 4300 1 0.2 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 60 HD208816 STIS/N ACCUM 0.2X0.2 E230H 3012 BINAXIS1=NO,BINAXIS2=NO 1 11 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 70 HD208816 STIS/N ACCUM 0.2X0.2 E230H 2862 BINAXIS2=NO,BINAXIS1=NO 1 9 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 80 HD208816 STIS/N ACCUM 0.2X0.2 E230H 2713 BINAXIS1=NO,BINAXIS2=NO 1 8 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 90 HD208816 STIS/N ACCUM 0.2X0.2 E230H 2563 BINAXIS1=NO,BINAXIS2=NO 1 9 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 100 HD208816 STIS/N ACCUM 0.2X0.2 E230H 2413 BINAXIS1=NO,BINAXIS2=NO 1 11 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 110 HD208816 STIS/N ACCUM 0.2X0.2 E230H 2263 BINAXIS1=NO,BINAXIS2=NO 2 8 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 120 HD208816 STIS/N ACCUM 0.2X0.2 E230M 1978 BINAXIS1=NO,BINAXIS2=NO 2 500 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9231( 6) - 01/20/03 09:44 - [ 10] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 130 HD208816 STIS/F ACCUM 0.2X0.2 E140M 1425 BINAXIS1=NO,BINAXIS2=NO 2 10 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9231( 6) - 01/20/03 09:44 - [ 11] Summary Form for Proposal 9231 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F25ND5 52X0.5 0.2X0.2 1 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/NUV-MAMA STIS/FUV-MAMA FGS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ACQ/PEAK TRANS ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=2 GAIN=1 BINAXIS1=1 BINAXIS2=1 BINAXIS2=NO BINAXIS1=NO SCANS=24 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CVZ BETWEEN 02-Aug-2001 AND 14-Aug-2001 SEQ 10-130 NON-INT CVZ ORIENT 357D TO 27D ORIENT 177D TO 207D BETWEEN 26-Aug-2002 AND 07-Sep-2002 SEQ 10-150 NON-INT NO SPLIT GS ACQ SCENARIO SINGLE CVZ BETWEEN 01-Sep-2003 AND 01-Jan-2004 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G230LB G430L E230H E230M E140M E140H F5ND ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD208816 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 2375 4300 3012 2862 2713 2563 2413 2263 1978 1425 1526 1343 ------------------------------------------------------------------------------------------------------------------------------------