9037( 9) - 01/10/02 06:45 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9037 Version: 9 Check-in Date: 10-Jan-2002 06:44:06 1.Proposal Title: Imaging the Dust Disk around Epsilon Eridani ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 10 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Mario Livio Space Telescope Science Institute CoI: Dr. Al Schultz Space Telescope Science Institute N CoI: Dr. Bruce Woodgate Goddard Space Flight Center N CoI: Dr. Sara Heap Goddard Space Flight Center N CoI: Dr. Philip Plait Goddard Space Flight Center N CoI: Dr. Theodore Gull Goddard Space Flight Center N CoI: Dr. Holland Ford Space Telescope Science Institute N CoI: Dr. Garth Illingworth Lick Observatory N CoI: Dr. David Golimowski The Johns Hopkins University N CoI: Dr. Kailash Sahu Space Telescope Science Institute N CoI: Dr. Mark Clampin Space Telescope Science Institute N CoI: Dr. Carol Grady Goddard Space Flight Center N CoI: Dr. John Krist Space Telescope Science Institute N CoI: Dr. Charles Proffitt Space Telescope Science Institute N CoI: Dr. Daniela Calzetti Space Telescope Science Institute N CoI: Dr. Carey Lisse Space Telescope Science Institute N CoI: Dr. Ronald Gilliland Space Telescope Science Institute N CoI: Dr. Glenn Schneider Univ. of Arizona N CoI: Dr. Andrew Fruchter Space Telescope Science Institute N ------------------------------------------------------------------------------------ 5. Abstract Epsilon Eridani is the closest star to the Sun, around which a planet has been discovered. An asymmetric dust disk around the star has been detected in sub- millimeter observations. The clumps in the disk have been interpreted as resulting from resonant interaction, and the pattern has been predicted to revolve around star at a rate of ~0.7^degrees per year. We propose first epoch observations of the dust disk with STIS, to be followed up in subsequent cycles. These observations will not only reveal what may be the first extra-solar `Kuiper belt', but will also provide a crucial step in the development of observational techniques that can determine the presence and properties of planets, from the visible morphology of the disks around the parent stars. ------------------------------------------------------------------------------------ 9037( 9) - 01/10/02 06:45 - [ 2] Observations Description ------------------------ Epsilon Eri and our proposed PSF calibrator are both nearby, high proper motion stars. Coordinates and proper motions are taken from the Hipparcos catalog. We will first acquire the star, and then use a small angle maneuver (POS-TARG) to place the star 31" west from the center of the STIS detector active area (as shown in Fig. 1). Experience with such maneuvers indicates that the star can be reproducibly positioned to within 0.2 pixels, and will experience a jitter of similar order in the course of the observation. Portions of the stellar diffraction spikes will be visible in the STIS CCD field of view, and will be available for registering the stellar data and the PSF star to a common image centroid. The background stars in the field can also be used for centroiding. The precise spacecraft orientation is not critical but must ensure that the brightest sub-millimeter knot is well within the STIS field of view. The inner edge of the disk and the outer edge, as seen in the sub-millimeter will simultaneously be in the STIS FOV. This strategy will allow us to take exposures with integration times of ~110 sec without saturating the CCD. This would require that we use CR-SPLIT=5 for observations during each orbit. As is common with other coronographic imagery, the bulk of the signal in the raw observations will be the residual PSF of Epsilon Eri. The PSF at this stellar location will be determined by similar observations of Delta Eri (see Special Requirements, below). Need for Three Spacecraft Orientations: Our experience with STIS indicates that 3 observations, made with different roll angles, are needed for separation of circumstellar nebulosity from the HST+STIS PSF. This will be critical in the detection of bright knots in a face-on disk in the presence of the stellar PSF. Three observations separated by 11.5^degrees each in spacecraft orientation result in displacement of features 10" from the star, the inner edge of the disk, by 3.5" (~70 STIS pixels), and should be adequate to ensure imaging of the knot in both images on different parts of the CCD. As explained in the proposal, we will need about 5000 sec of integration on target, which will require 1 orbits per orientation. We thus need a total of 3 orbits on target. (The WFPC2 images show several stellar sources in the field, which can be used for combining the images.) To subtract the PSF contribution, we need to take images of a nearby K-star (Delta Eri) with the same spectral type and similar V magnitude, at exactly the same location, which will require an additional 3 orbits. Real Time Justification ----------------------- Separation of the circumstellar nebulosity from the residual PSF, even when the star is placed outside the STIS FOV, requires subtraction of a PSF standard star obtained with a similar observing strategy, and at the same location, since structure in the STIS PSF is known to be a function of position in the STIS field of view. The STIS GTO experience with coronographic observations has indicated that it is essential that the PSF star be close in color (Delta(B- V)<=0.08) to the science target. Given the faintness of Epsilon Eri's debris disk it is also desirable to minimize breathing residuals by obtaining the PSF observations from a star nearby on the sky, where the spacecraft thermal conditions will be similar to that of the program star observations. We are therefore requesting that the calibration observations be performed within 1.5 hours of the time of the science observations. The observations are distributed as follows. There are 3 visits, each of 2 orbits. The very first orbit is expected to be slightly thermally unstable. This orbit will be used to observe the PSF-star, by placing it exactly at the same location as the position of Eps -Eri in the following orbit. The second orbit is used to observe Eps-Eri. (There is a planned cycle 10 calibration proposal which can be used prior to these observations to verify that there is no glint at this location). In the 2nd visit, the orientation is changed by 11.5 degrees. The 4th orbit will be used to observe the PSF-star by placing the star exactly at the same location of Eps-Eri in the 3rd orbit. For the 3rd visit, the orientation will be changed by a further 11.5 degrees. Calibration Justification ------------------------- Real_Time_Justification Additional Comments ------------------- ------------------------------------------------------------------------------------ 9037( 9) - 01/10/02 06:45 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 EPSILON- STAR, DISK RA=03H 32M 56.42S +/- 0.2", DEC= J2000 V = 3.726+/-0.002 ERIDANI -9D 27' 29.9" +/- 0.7" TYPE=K2V Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1991.25 -0.066 0.01797 0.31075 2 EPSILON- STAR, DISK RA-OFF=2.063319S+/- 0.006S, DEC- J2000 V = 3.726+/-0.002 ERIDANI-OFF1 OFF=-5.383093"+/- 0.1", FROM 1 TYPE=K2V Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE Comments: For orient 55 3 EPSILON- STAR, DISK RA-OFF=1.968796S+/- 0.006S, DEC- J2000 V = 3.726+/-0.002 ERIDANI-OFF2 OFF=-10.602625"+/- 0.1", FROM 1 TYPE=K2V Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE Comments: For orient 65 4 EPSILON- STAR, DISK RA-OFF=1.814453S+/- 0.006S, DEC- J2000 V = 3.726+/-0.002 ERIDANI-OFF3 OFF=-15.500000"+/- 0.1", FROM 1 TYPE=K2V Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE Comments: For orient 75 5 EPSILON- STAR, DISK RA-OFF=1.604977S+/- 0.006S, DEC- J2000 V = 3.726+/-0.002 ERIDANI-OFF4 OFF=-19.926416"+/- 0.1", FROM 1 TYPE=K2V Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE Comments: For orient 85 6 DELTA- STAR RA=03H 43M 14.96S +/- 0.7", DEC= J2000 V = 3.52+/-0.002 ERIDANI -9D 45' 54.7" +/- 0.7" TYPE=K0IV Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE Comments: For orient 55 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1991.25 -0.006 0.742 0.110 7 DELTA- STAR RA-OFF=2.065192S+/- 0.006S, DEC- J2000 V = 3.52+/-0.002 ERIDANI-OFF1 OFF=-5.383093"+/- 0.1", FROM 6 TYPE=K0IV Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE 8 DELTA- STAR RA-OFF=1.606434S+/- 0.006S, DEC- J2000 V = 3.52+/-0.002 ERIDANI-OFF4 OFF=-19.926416"+/- 0.1", FROM 6 TYPE=K0IV Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE Comments: For orient 85 9037( 9) - 01/10/02 06:45 - [ 4] Visit: 01 Visit Priority: Visit Requirements: ORIENT 55D TO 55D SEQ 01-04 WITHIN 3.95 Orbits BETWEEN 01-JAN-2002 AND 28- FEB-2002 On Hold Comments: Additional Comments: Orient is chosen to put eps Eri about 5" off the chip. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 DELTA-ERIDA STIS/C ACQ F25ND3 MIRROR 1 0.1 S SEQ 10-30 NON-INT NI CD ------------------------------------------------------------------------------------------------------------------------------------ 20 DELTA-ERIDA STIS/C ACCUM F25ND3 MIRROR GAIN=4,CR-SPLIT=2 1 0.4 S MAX DUR MIN DUR NI CD Comments: confirmation image of Delta-eridani. ------------------------------------------------------------------------------------------------------------------------------------ 30 DELTA-ERIDA STIS/C ACCUM 50CCD MIRROR GAIN=4,CR-SPLIT=NO 15 109 S MAX DUR MIN DUR NI-OFF1 CD Comments: 15 unsaturated images of 109sec at off position ------------------------------------------------------------------------------------------------------------------------------------ 9037( 9) - 01/10/02 06:45 - [ 5] Visit: 02 Visit Priority: Visit Requirements: ORIENT 55D TO 55D On Hold Comments: Additional Comments: Orient is chosen to put eps Eri about 5" off the chip. If possible use same guide stars for visits 02, 03, 04, 05 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 EPSILON-ERI STIS/C ACQ F25ND3 MIRROR 1 0.1 S SEQ 10-30 NON-INT DANI CD ------------------------------------------------------------------------------------------------------------------------------------ 20 EPSILON-ERI STIS/C ACCUM F25ND3 MIRROR GAIN=4,CR-SPLIT=2 1 0.6 S MAX DUR MIN DUR DANI CD Comments: A confirmation image of Eps Eri. ------------------------------------------------------------------------------------------------------------------------------------ 30 EPSILON-ERI STIS/C ACCUM 50CCD MIRROR GAIN=4,CR-SPLIT=NO 15 109 S MAX DUR MIN DUR DANI-OFF1 CD Comments: 15 unsaturated images of 109sec at off pos, star is 5" from edge of CCD ------------------------------------------------------------------------------------------------------------------------------------ 9037( 9) - 01/10/02 06:45 - [ 6] Visit: 03 Visit Priority: Visit Requirements: ORIENT 65D TO 65D On Hold Comments: Additional Comments: If possible use same guide stars for visits 02, 03, 04, 05 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 EPSILON-ERI STIS/C ACQ F25ND3 MIRROR 1 0.1 S SEQ 10-30 NON-INT DANI CD ------------------------------------------------------------------------------------------------------------------------------------ 20 EPSILON-ERI STIS/C ACCUM F25ND3 MIRROR GAIN=4,CR-SPLIT=2 1 0.6 S MAX DUR MIN DUR DANI CD Comments: A confirmation image of Eps Eri. ------------------------------------------------------------------------------------------------------------------------------------ 30 EPSILON-ERI STIS/C ACCUM 50CCD MIRROR GAIN=4,CR-SPLIT=NO 15 109 S MAX DUR MIN DUR DANI-OFF2 CD Comments: 15 unsaturated images of 109sec at off2 pos, ------------------------------------------------------------------------------------------------------------------------------------ 9037( 9) - 01/10/02 06:45 - [ 7] Visit: 04 Visit Priority: Visit Requirements: ORIENT 75D TO 75D On Hold Comments: Additional Comments: Orient is chosen to put eps Eri about 5" off the chip. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 EPSILON-ERI STIS/C ACQ F25ND3 MIRROR 1 0.1 S SEQ 10-30 NON-INT DANI CD ------------------------------------------------------------------------------------------------------------------------------------ 20 EPSILON-ERI STIS/C ACCUM F25ND3 MIRROR GAIN=4,CR-SPLIT=2 1 0.4 S MAX DUR MIN DUR DANI CD Comments: confirmation image of eps-eridani. ------------------------------------------------------------------------------------------------------------------------------------ 30 EPSILON-ERI STIS/C ACCUM 50CCD MIRROR GAIN=4,CR-SPLIT=NO 15 109 S MAX DUR MIN DUR DANI-OFF3 CD Comments: 15 unsaturated images of 109sec at off3 position of eps eri. ------------------------------------------------------------------------------------------------------------------------------------ 9037( 9) - 01/10/02 06:45 - [ 8] Visit: 05 Visit Priority: Visit Requirements: ORIENT 85D TO 85D AFTER 04 BY 0 Orbits TO 1.95 Orbits SEQ 05-06 WITHIN 1.95 Orbits On Hold Comments: Additional Comments: Orient is chosen to put eps Eri about 5" off the chip. If possible use same guide stars for visits 02, 03, 04, 05 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 EPSILON-ERI STIS/C ACQ F25ND3 MIRROR 1 0.1 S SEQ 10-30 NON-INT DANI CD ------------------------------------------------------------------------------------------------------------------------------------ 20 EPSILON-ERI STIS/C ACCUM F25ND3 MIRROR GAIN=4,CR-SPLIT=2 1 0.4 S MAX DUR MIN DUR DANI CD Comments: confirmation image of eps-eridani. ------------------------------------------------------------------------------------------------------------------------------------ 30 EPSILON-ERI STIS/C ACCUM 50CCD MIRROR GAIN=4,CR-SPLIT=NO 15 109 S MAX DUR MIN DUR DANI-OFF4 CD Comments: 15 unsaturated images of 109sec at off4 position of eps eri. ------------------------------------------------------------------------------------------------------------------------------------ 9037( 9) - 01/10/02 06:45 - [ 9] Visit: 06 Visit Priority: Visit Requirements: ORIENT 85D TO 85D 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 DELTA-ERIDA STIS/C ACQ F25ND3 MIRROR 1 0.1 S SEQ 10-30 NON-INT NI CD ------------------------------------------------------------------------------------------------------------------------------------ 20 DELTA-ERIDA STIS/C ACCUM F25ND3 MIRROR GAIN=4,CR-SPLIT=2 1 0.6 S MAX DUR MIN DUR NI CD Comments: A confirmation image of delta Eri. ------------------------------------------------------------------------------------------------------------------------------------ 30 DELTA-ERIDA STIS/C ACCUM 50CCD MIRROR GAIN=4,CR-SPLIT=NO 15 109 S MAX DUR MIN DUR NI-OFF4 CD Comments: 15 unsaturated images of 109sec at off4 pos, star is 5" from edge of CCD ------------------------------------------------------------------------------------------------------------------------------------ 9037( 9) - 01/10/02 06:45 - [ 10] Summary Form for Proposal 9037 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F25ND3 50CCD ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters GAIN=4 CR-SPLIT=2 CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 55D TO 55D SEQ 01-04 WITHIN 3.95 Orbits BETWEEN 01-JAN-2002 AND 28-FEB-2002 SEQ 10-30 NON-INT MAX DUR MIN DUR ORIENT 55D TO 55D ORIENT 65D TO 65D ORIENT 75D TO 75D ORIENT 85D TO 85D AFTER 04 BY 0 Orbits TO 1.95 Orbits SEQ 05-06 WITHIN 1.95 Orbits ORIENT 85D TO 85D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names DELTA-ERIDANI DELTA-ERIDANI-OFF1 EPSILON-ERIDANI EPSILON-ERIDANI-OFF1 EPSILON-ERIDANI-OFF2 EPSILON-ERIDANI-OFF3 EPSILON-ERIDANI-OFF4 DELTA-ERIDANI-OFF4 ------------------------------------------------------------------------------------------------------------------------------------