6074( 13) - 07/11/96 10:31 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6074 Version: 13 Check-in Date: 11-Jul-1996 10:26:16 1.Proposal Title: Kinematics of the Disc of TT Hydrae ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Cool Stars GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Joel A. Eaton TENNESSEE STATE UNIVERSITY CoI: Gregory W. Henry Tennessee State University N ------------------------------------------------------------------------------------ 6. Abstract Components of many types of binary stars, as well as other diverse astrophysical objects, are accreting material through discs. Some of the Algol binaries provide exceptionally bright examples of this phenomenon which allow us observe and model the inner regions of accretion discs in detail. Not only do their cool companion stars give rather high accretion rates through Roche-lobe overflow, but the underbareclipses of the hot accreting stars by these cool companions let us sample the undiluted disc emissions. We will obtain high-dispersion spectra in the underbartotal underbareclipse of TT Hya (B9.5 V+K0 III-IV), a particularly bright Algol binary known to show absorptions of a warm extended accretion disk in its ultraviolet spectrum. These spectra will provide a detailed understand of accretion by allowing us to identify the process exciting the emission lines and to use the kinematics of the line-scattering regions (1) to distinguish between contributions of the disk and of a wind, (2) to ascertain how close to the disc any biploar wind from the system is formed, and (3) to determine the degree to which the disc rotates as a solid body. ------------------------------------------------------------------------------------ 6074( 13) - 07/11/96 10:31 - [ 2] Observations Description ------------------------ We are proposing an HRS observation during a total eclipse of TT Hya. These will consist of two types: (1) a survey of the emission lines in the 1200-1760 A range and (2) profiles of a few strong lines. Observations at low dispersion: We will use grating G140L (DelLam ~ 0.6 A) to survey the wavelengths between 1200 and 1760 A in two steps. According to Plavec (1988), this wavelength range has a flux near 2.0 x 10^-13 erg/cm^2/s/A (averaged over the weaker lines), so with a sensitivity of ~ 1.5times10^13 for the 1200-1480 A spectrum, an exposure time of 15 min will reach the desired S/N of 50. For 1480-1760 A, the lower sensitivity (~ 0.4 x 10^13) means an 18-minute exposure will reach S/N=30. This set of two survey spectra should fit into a single SC orbit, with visibility of 53 min. The spectra of individual lines are to be made with gratings G160M and G270M. The specific lines to be observed are the resonance doublets of Si IV (Lam1400) and Mg II (Lam2800) and some Fe II lines at long wavelength. These may be observed in three settings, G160M at 1400 A for Si IV (40 min for S/N = 30 at peak of lines), G270M at 2792 A for Mg II (15 min for S/N = 60), and G270M at 2630 Angstrom\\ for Fe II lines (15 min for S/N = 40). With total eclipse lasting 5 hours, there will be 3-4 spacecraft orbits in total eclipse on each of the binary star's orbits. Orbits near the start and end of totality will catch the B star sufficiently occulted to observe the bright emission lines at high dispersion. Our strategy is to observe for 6 orbits during a single eclipse of TT Hya. Orbit 1, the last SC orbit before the eclipse becomes total, is to acquire the star and prepare the camera (26 min), then to take a single Mg II spectrum. Orbit 2, the first in total eclipse, is to obtain a single Si IV spectrum at 1400 A. Orbit 3, in total eclipse, is to obtain a pair of spectra at 2800 and 2630 A. Orbit 4, in total eclipse, is to obtain a pair of short-wavelength survey spectra covering 1200-1760 A. Orbit 5, in or just past total eclipse, is a repeat Orbit 2 to measure changes in the Si IV profiles. Orbit 6, somewhat past total eclipse, is a repeat Orbit 3 to measure changes in Mg II line profiles. Real Time Justification ----------------------- For this program to be effective, the observations must be scheduled during a TOTAL ECLIPSE of TT Hya, starting just before the eclipse becomes total. The total eclipse lasts 5 hours, and there is a reasonably well determined ephemeris, JD(Hel)2,448,743.8250 + 6.9535526*Epoch for phases determined with respect to mid-primary eclipse, which can be used to predict times of minimum. Some specific times in the range of dates 1995 Dec.--1996 May were listed in Table 1 of the original proposal, although they are now slightly wrong, and we expect to predict these times more precisely with photometric observations are now obtaining in early 1995 with our automatic photometric telescope. Observations should start about 0.030 phase units before mid eclipse, or 0.209 days. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 6074( 13) - 07/11/96 10:31 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: __User-Comments__ , ------------------------------------------------------------------------------------ 6074( 13) - 07/11/96 10:31 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD97528 STAR,Interacting RA = 11H 13M 12.50S +/- 0.01S, J2000 V=11. V = 9.1 Binary,Algol DEC = -26D 27' 54.1" +/- 0.1", B-V = 0.97 System,Accretion Disk PLATE-ID=04NQ E(B-V) = 0.00 Comments: Coordinates are from Hipparcos INCA. RA,DEC, and proper motions are from the SAO Catalogue; parallax is from a photometric distance.The magnitude and color listed are for total eclipse when most of the observations will be taken; outside eclipse, the light of the star is 2 mag brighter, V=7.25 and B-V=0.16. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 0.0014 0.014 0.004 6074( 13) - 07/11/96 10:31 - [ 5] Visit: 01 Visit Requirements: PERIOD 6.9535526D AND ZERO-PHASE JD2448743.616 On Hold Comments: Additional Comments: I need these six orbits scheduled without any interruption, during a primary eclipse of the Algol binary TT Hya. I have specified the observations for each orbit for scientific reasons, and it is imperative that they not be pushed into later orbits. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 HD97528 HRS ACQ 2.0 MIRROR-N2 1 1.8 S PHASE 0.00 TO 0.01 ONBOARD ACQ FOR 2-12 SEQ NON-INT 1-3 Comments: This acquisition assumes the star is a 8-9 mag unreddened K0 star, as it will roughly be in and near total eclipse, plus a roughly 10th mag A0 star. ------------------------------------------------------------------------------------------------------------------------------------ 2 WAVE HRS ACCUM SC2 G270M 2792 1 DEF Comments: Wavelength calibration for exposure 3. ------------------------------------------------------------------------------------------------------------------------------------ 3 HD97528 HRS ACCUM 2.0 G270M 2792 FP-SPLIT=STD 1 1196.8 Comments: This exposure must be in the 1st orbit only. If it gets pushed into the second orbit, it runis the observing sequence. ------------------------------------------------------------------------------------------------------------------------------------ 4 WAVE HRS ACCUM SC2 G160M 1400 1 163.2 S SEQ NON-INT 4-5 Comments: Wavelength calibration for exposure 5. END OF 1ST ORBIT ------------------------------------------------------------------------------------------------------------------------------------ 5 HD97528 HRS ACCUM 2.0 G160M 1400 FP-SPLIT=STD 1 2393.6 NO SPLIT Comments: This observation is designed for the 2nd orbit; it must not be pushed into the 3rd. ------------------------------------------------------------------------------------------------------------------------------------ 6 HD97528 HRS ACCUM 2.0 G270M 2792 FP-SPLIT=STD 1 979.2 S SEQ NON-INT 6-7 ------------------------------------------------------------------------------------------------------------------------------------ 7 HD97528 HRS ACCUM 2.0 G270M 2630 FP-SPLIT=STD 1 979.2 S Comments: Exposures 6 and 7 are designed for the 3rd orbit. ------------------------------------------------------------------------------------------------------------------------------------ 8 HD97528 HRS ACCUM 2.0 G140L 1340 1 924.8 S SEQ NON-INT 8-9 ------------------------------------------------------------------------------------------------------------------------------------ 9 HD97528 HRS ACCUM 2.0 G140L 1620 1 1196.8 Comments: Exposures 8 and 9 are designed for the 4th orbit. ------------------------------------------------------------------------------------------------------------------------------------ 10 HD97528 HRS ACCUM 2.0 G160M 1400 FP-SPLIT=STD 1 2393.6 NO SPLIT Comments: This observations is designed for the 5th orbit only. ------------------------------------------------------------------------------------------------------------------------------------ 11 HD97528 HRS ACCUM 2.0 G270M 2792 FP-SPLIT=STD 1 979.2 S SEQ NON-INT 11-12 ------------------------------------------------------------------------------------------------------------------------------------ 6074( 13) - 07/11/96 10:31 - [ 6] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 12 HD97528 HRS ACCUM 2.0 G270M 2630 FP-SPLIT=STD 1 979.2 S Comments: Exposures 11 and 12 are intended for the 6th orbit. ------------------------------------------------------------------------------------------------------------------------------------ 6074( 13) - 07/11/96 10:31 - [ 7] Summary Form for Proposal 6074 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Cool Stars ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PERIOD 6.9535526D AND ZERO-PHASE JD2448743.616 PHASE 0.00 TO 0.01 ONBOARD ACQ FOR 2-12 SEQ NON-INT 1-3 SEQ NON-INT 4-5 NO SPLIT SEQ NON-INT 6-7 SEQ NON-INT 8-9 SEQ NON-INT 11-12 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 G270M G160M G140L ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD97528 WAVE ------------------------------------------------------------------------------------------------------------------------------------