9769( 12) - 01/15/04 10:45 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9769 Version: 12 Check-in Date: 15-Jan-2004 10:44:08 1.Proposal Title: STIS Observations of Orbital and Rotational Variations in the Unique Post-Common Envelope System HS1136+6646 ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 12 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Dr. Jay B. Holberg University of Arizona CoI: Mr. David K. Sing University of Arizona N CoI: Mr. Simon Good University of Leicester N CoI: Dr. Martin Barstow University of Leicester N CoI: Dr. Matthew Burleigh University of Leicester N CoI: Dr. Terry D. Oswalt Florida Institute of Technology N CoI: Dr. Steve B. Howell University of California - Riverside N ------------------------------------------------------------------------------------ 5. Abstract HS1136+6646 is a recently discovered close-binary system consisting of a hot (Teff ~ 120, 000 K) DAO white dwarf and a K7V main sequence companion. It is unique in being a relatively bright, nearby example of both a very young post-common envelope system and a pre-cataclysmic variable system. Although the K star component of HS1136+6646 has now been well studied from the ground, the white dwarf can only be effectively studied at UV wavelengths from space. We propose STIS observations of HS1136+6646 which focus specifically on the nature of the white dwarf, i.e., its mass, temperature, age, photospheric composition and possible magnetic field. High- dispersion echelle spectra, taken at quadrature of the 0.83607 day orbital period of the system will provide an accurate determination of the gravitational redshift of the white dwarf. ------------------------------------------------------------------------------------ 9769( 12) - 01/15/04 10:45 - [ 2] Observations Description ------------------------ HS1136+6646 resides in the CVZ and thus can be viewed continuously. We propose to achieve our objectives using one visit, totaling two orbits. The visit will begin with an E140H (lambda =1234, 0.2"x0.2" aperture) exposure of 5740 s (S/N ~25) centered on the white dwarf velocity maximum. The purpose of the H grating is three-fold: 1) it resolves the velocity structure of the ISM, which is important for the interpretation of both the subsequent E140M spectra and existing FUSE spectra; 2) it resolves key photospheric resonance lines such as NV lambda = 1240 angst. that can be used to analyze photospheric stratifictation (see Holberg et al. 1999, Schuh et al. 2001); 3) it provides the best opportunity to resolve Zeeman split lines and circumstellar features (see Bannister et al. 2003). After the E140H observation, the visit will continue with a series of E140M (lambda =1425 angst.) spectra with exposure times of 1500 s (S/N ~20). The coaddition of the E140M spectrum will provide a good (S/N ~35) spectra with which to analyze the photosphere of the white dwarf (see Holberg et al. 2000 for discussion of similar spectra of G191-B2B). Our exposure estimates and S/N calculations are based on the STIS exposure calculations and flux estimates based on FUSE and ground-based observations. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9769( 12) - 01/15/04 10:45 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HS1136+6646 STAR, COMPOSITE RA=11H39M6.02S +/- 0.2", J2000 V = 13.62+/-0.11 SPECTRAL TYPE, DA, K V- DEC=+66D30'18.2" +/- 0.2", IV PLATE-ID=01RM Coordinate Source: GUIDE_STAR_CATALOG Comments: HS1136+6646 is a binary star consisting of a DAO white dwarf and KIV. 9769( 12) - 01/15/04 10:45 - [ 4] Visit: 01 Visit Priority: Visit Requirements: PCS MODE FINE; CVZ; Period 0.83607 D AND ZERO-PHASE JD2452360.566 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 HS1136+6646 STIS/C ACQ 50CCD MIRROR 1 0.2 S CD ------------------------------------------------------------------------------------------------------------------------------------ 2 HS1136+6646 STIS/F ACCUM 0.2X0.2 E140H 1234 1 4048 S PHASE 0.216319 TO UV-MAM 0.283681 A ------------------------------------------------------------------------------------------------------------------------------------ 9769( 12) - 01/15/04 10:45 - [ 5] Visit: 02 Visit Priority: Visit Requirements: CVZ; AFTER 01; Period 0.83607 D AND ZERO-PHASE JD2452360.566 On Hold Comments: Additional Comments: In order to catch HS1136+6646 at the velocity maximum, exposures should start at phase 0.7192053 which is 0.36 days after the velocity minimum captured by visit one. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 HS1136+6646 STIS/C ACQ 50CCD MIRROR 1 0.2 S CD ------------------------------------------------------------------------------------------------------------------------------------ 2 HS1136+6646 STIS/F ACCUM 0.2X0.2 E140M 1425 1 1400 S PHASE 0.7192053 TO UV-MAM 0.738586 A ------------------------------------------------------------------------------------------------------------------------------------ 3 HS1136+6646 STIS/F ACCUM 0.2X0.2 E140M 1425 1 1400 S NEW ALIGNMENT UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 4 HS1136+6646 STIS/F ACCUM 0.2X0.2 E140M 1425 1 1400 S NEW ALIGNMENT UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9769( 12) - 01/15/04 10:45 - [ 6] Summary Form for Proposal 9769 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 50CCD 0.2X0.2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PCS MODE FINE; CVZ; Period 0.83607 D AND ZERO-PHASE JD2452360.566 PHASE 0.216319 TO 0.283681 CVZ; AFTER 01; Period 0.83607 D AND ZERO-PHASE JD2452360.566 PHASE 0.7192053 TO 0.738586 NEW ALIGNMENT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR E140H E140M ------------------------------------------------------------------------------------------------------------------------------------ Target Names HS1136+6646 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 1234 1425 ------------------------------------------------------------------------------------------------------------------------------------