9742( 3) - 05/15/03 18:59 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9742 Version: 3 Check-in Date: 15-May-2003 18:57:57 1.Proposal Title: Natural Coronagraphic Imaging of KH 15D ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 12 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Prof. William Herbst Wesleyan University CoI: Ms. Catrina M. Hamilton Wesleyan University N CoI: Dr. Reinhard Mundt Max-Planck-Institut fur Astronomie, N Heidelberg CoI: Dr. Coryn A. L. Bailer-Jones Max-Planck-Institut fur Astronomie, N Heidelberg CoI: Prof. Ray Jayawardhana University of Michigan N ------------------------------------------------------------------------------------ 5. Abstract We propose to obtain V, H-alpha and [SII] images of the unique, eclipsing pre-main sequence star KH 15D near minimum light with the ACS/HRC. This solar-like star in NGC 2264, near the Cone Nebula, is fortuitously positioned with respect to our line of sight. Every 48.36 days its photosphere and accretion zone are progressively occulted and then revealed by an eclipsing body, which is evidently non-luminous, extended circumstellar matter in the star's vicinity. Dramatic spectral evolution is seen during these "natural cononagraphic" events that is revealing the structure of the accretion zone on spatial scales (~0.01 AU or less) that may not be achieved in other sources for decades to come, if ever. It is important to know whether this object is unique only in its orientation and not in its basic structure. Our observations will test the hypothesis that KH 15D at minimum light looks like nearly edge-on disk/jet systems around stars of similar mass and age in closer star forming regions such as Tau/Aur or MBM 12. We argue that the disk and jet will be resolved and will provide new constraints on this system. If not resolved, the data will at least constrain the scattering and jet emission zones to be remarkably close to the star (~10 AU). In either case, we will have important new information on the nature of this unique object. ------------------------------------------------------------------------------------ 9742( 3) - 05/15/03 18:59 - [ 2] Observations Description ------------------------ Our plan is to test, as rigorously as possible, the hypothesis that KH15D can be resolved as an edge-on disk and orthogonal jet during minimum light. To accomplish this, we require the best possible resolution that can be achieved with HST and, therefore the ACS/HRC. Observing at V and using a patterned dither we may expect to approach the resolution limit of about 0.03 arc-sec according to the ACS Instrument Handbook. Since the expected total magnitude of the object is V=19.5 we will achieve a S/N ratio well in excells of 100 for average observing conditions according to the ACS/ETC. The optimal number of dithered images is estimated to be 6 for this project, leading to individual exposure times of about 7 min. With this plan, we should be able to either resolve the scattered light region or constrain its radius to be smaller that about 10 AU. To resolve the jet we choose to observe in [SII], using a ramp filter, and in H-alpha, using the narrow filter. The ETC suggests we can achieve a S/N of about 100 in one orbit in H-alpha and S/N of about 30 in [SII] in two orbits. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9742( 3) - 05/15/03 18:59 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 KH15D STAR, T TAURI STAR RA=06H41M10.33S +/- 0.3", J2000 V = 19.5 DEC=+09D28'34.1" +/- 0.3" Coordinate Source: Other_Source: HAMILTON ET AL. (2001) APJ 554, L201 9742( 3) - 05/15/03 18:59 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type ACS-HRC-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.15 Coordinate_Frame POS-TARG Pattern_Orient 19.89 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 9742( 3) - 05/15/03 18:59 - [ 5] Visit: 01 Visit Priority: Visit Requirements: PCS MODE FINE SCHED 30% ORIENT 302.0D TO 2.0 D ORIENT 212.0D TO 272.0 D ORIENT 122.0D TO 182.0 D ORIENT 32.0D TO 92.0 D BETWEEN 15-SEP- 2003:00:00:00 AND 01-APR-2004:00:00:00 Period 48.36 D AND ZERO-PHASE JD2452352.26 On Hold Comments: Additional Comments: See comment to Visit 02 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 KH15D ACS/HR ACCUM HRC F555W CR-SPLIT=NO 1 625 S PHASE 0.9 TO 0.1 PATTERN C 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 KH15D ACS/HR ACCUM HRC F658N CR-SPLIT=NO 1 640 S PHASE 0.9 TO 0.1 PATTERN C 1 2 ------------------------------------------------------------------------------------------------------------------------------------ 9742( 3) - 05/15/03 18:59 - [ 6] Visit: 02 Visit Priority: Visit Requirements: PCS MODE FINE SCHED 30% ORIENT 302.0D TO 2.0 D ORIENT 212.0D TO 272.0 D ORIENT 122.0D TO 182.0 D ORIENT 32.0D TO 92.0 D BETWEEN 15-SEP- 2003:00:00:00 AND 01-APR-2004:00:00:00 Period 48.36 D AND ZERO-PHASE JD2452352.26 GROUP 01, 02 WITHIN 5 Orbits On Hold Comments: Additional Comments: Orientation Requirements are intended to avoid having diffraction spikes from a V=7 mag. star (HD 47887) cross the HRC aperture within about 10- arcsecs of our target. The bright star is located at position angle 196.7 (i.e. southwest) from our target and is 38 arc-secs from it. It was assumed in this calculation that the diffraction spikes would lie along the U3 axis and be perpendicular to it. The orientation requirements for Visit 01 are identical. The Timing Requirement is for the star to be in eclipse and it is necessary for the {SII} images to be obtained with 0.2 days (about 5 orbits) of the V and H-alpha images (Visit 01) so that there is no substantial change in the illumination of the nebula between these images. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 KH15D ACS/HR ACCUM HRC FR656N 6724 CR-SPLIT=NO 1 625 S PHASE 0.9 TO 0.1 PATTERN C 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 KH15D ACS/HR ACCUM HRC FR656N 6724 CR-SPLIT=NO 1 640 S PHASE 0.9 TO 0.1 PATTERN C 1 2 ------------------------------------------------------------------------------------------------------------------------------------ 9742( 3) - 05/15/03 18:59 - [ 7] Summary Form for Proposal 9742 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures HRC ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/HRC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PCS MODE FINE SCHED 30% ORIENT 302.0D TO 2.0 D ORIENT 212.0D TO 272.0 D ORIENT 122.0D TO 182.0 D ORIENT 32.0D TO 92.0 D BETWEEN 15-SEP-2003 00 00 00 AND 01-APR-2004 00 00 00 Period 48.36 D AND ZERO-PHASE JD2452352.26 PHASE 0.9 TO 0.1 PATTERN 1 1 PHASE 0.9 TO 0.1 PATTERN 1 2 PCS MODE FINE SCHED 30% ORIENT 302.0D TO 2.0 D ORIENT 212.0D TO 272.0 D ORIENT 122.0D TO 182.0 D ORIENT 32.0D TO 92.0 D BETWEEN 15-SEP-2003 00 00 00 AND 01-APR-2004 00 00 00 Period 48.36 D AND ZERO-PHASE JD2452352.26 GROUP 01, 02 WITHIN 5 Orbits ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W F658N FR656N ------------------------------------------------------------------------------------------------------------------------------------ Target Names KH15D ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 6724 ------------------------------------------------------------------------------------------------------------------------------------