11291( 3) - 05/14/07 08:22 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 11291 Version: 3 Check-in Time: 14-May-2007 12:22:20 STScI Edit Number: 0 Title Following Eta Carinae's Change of State ------------------------------------------------------------------------------------ Type Cycle Parallel Pointing Tolerance GO 16 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Kris Davidson University of Minnesota - Twin Cities CoI: Dr. Roberta M. Humphreys University of Minnesota - Twin Cities N CoI: Dr. Kazunori Ishibashi Massachusetts Institute of Technology N CoI: Mr. Michael Koppelman Clockwork Active Media Systems N CoI: Dr. John Carl Martin University of Illinois at Springfield N CoI: Dr. Otmar Stahl Landessternwarte Heidelberg N CoI: Dr. Nicholas B. Suntzeff National Optical Astronomy Observatories - N CTIO CoI: Dr. Nolan R. Walborn Space Telescope Science Institute N ------------------------------------------------------------------------------------ Abstract Eta Carinae is now known to be undergoing some unusually rapid changes on a timescale of several years. They are probably essential for modeling the star's long-term recovery from its Giant Eruption 160 years ago -- the prototype "supernova impostor" event. Since high spatial resolution is needed to isolate the central star, and the present state will probably not recur in the future, it is important to obtain HST data during the next two years. We propose a cost-effective set of ACS observations with three goals: (1) to obtain a continuing record of the star's rapid UV and visual brightening; (2) to lengthen the temporal baseline of ACS images enough to settle an important question concerning ejecta ages; and (3) to extend the record of morphological changes in the inner ejecta past the midpoint of eta Car's 5.5-year cycle. ------------------------------------------------------------------------------------ 11291( 3) - 05/14/07 08:22 - [ 2] Observations Description ------------------------ -- This plan, using WFPC2(PC), is a substitute for earlier ACS plan -- see Cycle 15 program 10844.-- We concentrate on WFPC2 filter F336W because it nearly matches ACS F330W. Primary goal is to monitor the UV brightness of the central object (Eta Car, the star itself). Central object is too bright for the longer-wavelength WFPC2 'M' and 'W' filters, and the 'N' filters are contaminated by emission lines whose brightness cannot be assessed with available instruments.-- We need at least two independent visits per year, with roughly uniform temporal spacing. This plan includes 3 one-orbit visits. We've chosen not to attempt a two-orbit visit because multicolor imaging has much lower priority than sampling the essential UV brightness trend. Real Time Justification ----------------------- Main goal is temporal coverage of progressive brightness trend. Calibration Justification ------------------------- -- none requested -- Additional Comments ------------------- (Regarding early scheduling within Cycle 16): Ground-based photometry suggests that a rapid change occurred a few weeks after our last Cy 15 ACS observation. Therefore, it would be prudent to get data as soon as possible now.-- Criteria for visit timing (3 visits): 1. Visit 1 should occur as soon as feasible (see above). 2. Visit 3 should occur near the end of Cycle 16, even if that is delayed. Eta Carinae is expected to have another "spectroscopic event" in January 2009, and if possible we should get data near that time. 3. Vist 2 should be roughly midway between the other two, but there is no need for it to be exactly midway. After the mid-point may be a little better than before. ------------------------------------------------------------------------------------ 11291( 3) - 05/14/07 08:22 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 ETA-CAR-A STAR, ETA CARINAE STAR, RA=10H45M3.6000S +/- 0.04S, J2000 V = 6.0+/-0.5 CIRCUMSTELLAR MATTER, DEC=-59D41'4.10" +/- 0.3", F(2600)=1.3+/-0.3 E-11 EJECTA, WIND, LUMINOUS PLATE-ID=ZZZQ F(3400)=1.7+/-0.4 E-11 BLUE VARIABLE F(6300)=2.4+/-0.60 E-11 Reference Frame: GSC1 Comments: IMPORTANT: Acquiring Eta Car is potentially tricky because of the surrounding Carina Nebula. In this region, bright nebulosity tends to hide large areas in ordinary wide-field plates. (VTT, for instance, is murky around Eta Car.) Therefore we fear that the area distribution of GSC2 guide stars contains "holes." Even worse, some official guide stars cannot be trusted because they're perturbed by nebular features seen with inadequate plate scale.-- All our previous acquisitions of this object, in the years 1991--2006, used special catalog ZZZQ, and it didn't cause any failures. The normal type of acquisition would PROBABLY work, but we're not sure. Therefore we specify ZZZQ in this plan.-- 11291( 3) - 05/14/07 08:22 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFPC2-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.559017 Line_Spacing 0.559017 Coordinate_Frame POS-TARG Pattern_Orient 26.56505 Angle_Between_Sides 143.130102 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 11291( 3) - 05/14/07 08:22 - [ 5] Visit: 01 Visit Priority: Visit Requirements: BEFORE 01-SEP-2007:00:00:00 On Hold Comments: Additional Comments: Visit 1 should be done as early as feasible, see notes elsewhere in this plan. Target may have changed appreciably since our last Cy 15 HST observations. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 ETA-CAR-A WFPC2 IMAGE PC1 F336W ATD-GAIN=15 1 0.11 S POS TARG 0,-1.5; PATTERN 1 1 Comments: Gain 15, because very high count rate in central object. Brightest pixel may saturate at one of the dither points, but probably not at all of them. ------------------------------------------------------------------------------------------------------------------------------------ 2 ETA-CAR-A WFPC2 IMAGE PC1 F336W ATD-GAIN=15 1 0.8 S POS TARG 0,-1.5; PATTERN 1 2 Comments: Gain 15, because very high count rate in central object. We use two different exposure times in order to get high dynamic range in surrounding ejecta. ------------------------------------------------------------------------------------------------------------------------------------ 3 ETA-CAR-A WFPC2 IMAGE PC1 F255W ATD-GAIN=15 1 0.6 S Comments: Minimal short-wvl observation for comparison with earlier ACS data. Count rate is expected to be high, but not as high as for the other filters. ------------------------------------------------------------------------------------------------------------------------------------ 4 ETA-CAR-A WFPC2 IMAGE PC1 F631N ATD-GAIN=15 1 0.11 S Comments: Minimal red observation, for comparison with many pre-2003 WFPC2(PC) F631N data. Very high count rate in central object. ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ ETA-CAR-A 1 WFPC2 IMAGE PC1 F336W 1 none none none 1 N/A ETA-CAR-A 1 WFPC2 IMAGE PC1 F336W 2 none none none 1 N/A ETA-CAR-A 1 WFPC2 IMAGE PC1 F336W 3 none none none 1 N/A ETA-CAR-A 1 WFPC2 IMAGE PC1 F336W 4 none none none 1 N/A ETA-CAR-A 2 WFPC2 IMAGE PC1 F336W 1 none none none 1 N/A ETA-CAR-A 2 WFPC2 IMAGE PC1 F336W 2 none none none 1 N/A ETA-CAR-A 2 WFPC2 IMAGE PC1 F336W 3 none none none 1 N/A ETA-CAR-A 2 WFPC2 IMAGE PC1 F336W 4 none none none 1 N/A 11291( 3) - 05/14/07 08:22 - [ 6] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ ETA-CAR-A 3 WFPC2 IMAGE PC1 F255W none none none none 1 N/A ETA-CAR-A 4 WFPC2 IMAGE PC1 F631N none none none none 1 N/A 11291( 3) - 05/14/07 08:22 - [ 7] Visit: 02 Visit Priority: Visit Requirements: AFTER 01 BY 150 D TO 260 D On Hold Comments: Additional Comments: Visit 2 should occur roughly midway between Visits 1 and 3, if feasible -- but it doesn't need to be exactly midway. The main requirement is that Visit 2 should not be close to either of the other two. . Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 ETA-CAR-A WFPC2 IMAGE PC1 F336W ATD-GAIN=15 1 0.11 S POS TARG 0,-1.5; PATTERN 1 1 Comments: Gain 15, because very high count rate in central object. Brightest pixel may saturate at one of the dither points, but probably not at all of them. ------------------------------------------------------------------------------------------------------------------------------------ 2 ETA-CAR-A WFPC2 IMAGE PC1 F336W ATD-GAIN=15 1 0.8 S POS TARG 0,-1.5; PATTERN 1 2 Comments: Gain 15, because very high count rate in central object. We use two different exposure times in order to get high dynamic range in surrounding ejecta. ------------------------------------------------------------------------------------------------------------------------------------ 3 ETA-CAR-A WFPC2 IMAGE PC1 F255W ATD-GAIN=15 1 0.6 S Comments: Minimal short-wvl observation for comparison with earlier ACS data. Count rate is expected to be high, but not as high as for the other filters. ------------------------------------------------------------------------------------------------------------------------------------ 4 ETA-CAR-A WFPC2 IMAGE PC1 F631N ATD-GAIN=15 1 0.11 S Comments: Minimal red observation, for comparison with many pre-2003 WFPC2(PC) F631N data. Very high count rate in central object. ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ ETA-CAR-A 1 WFPC2 IMAGE PC1 F336W 1 none none none 1 N/A ETA-CAR-A 1 WFPC2 IMAGE PC1 F336W 2 none none none 1 N/A ETA-CAR-A 1 WFPC2 IMAGE PC1 F336W 3 none none none 1 N/A ETA-CAR-A 1 WFPC2 IMAGE PC1 F336W 4 none none none 1 N/A ETA-CAR-A 2 WFPC2 IMAGE PC1 F336W 1 none none none 1 N/A ETA-CAR-A 2 WFPC2 IMAGE PC1 F336W 2 none none none 1 N/A ETA-CAR-A 2 WFPC2 IMAGE PC1 F336W 3 none none none 1 N/A ETA-CAR-A 2 WFPC2 IMAGE PC1 F336W 4 none none none 1 N/A 11291( 3) - 05/14/07 08:22 - [ 8] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ ETA-CAR-A 3 WFPC2 IMAGE PC1 F255W none none none none 1 N/A ETA-CAR-A 4 WFPC2 IMAGE PC1 F631N none none none none 1 N/A 11291( 3) - 05/14/07 08:22 - [ 9] Visit: 03 Visit Priority: Visit Requirements: AFTER 01-JUL-2008:00:00:00 On Hold Comments: Additional Comments: Visit 3 should occur near the end of Cycle 16, if feasible. Eta Carinae is expected to have an important "spectroscopic event" in January 2009, so we're especially interested in the brightness just before that. If the end of Cy 16 is delayed far enough, it may be useful for visit 3 to occur in January 2009, or close to that.-- Anyway, if a further delay in the end of Cy 16 is announced beforehand, then it will be advantageous to postpone Visit 3 accordingly. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 ETA-CAR-A WFPC2 IMAGE PC1 F336W ATD-GAIN=15 1 0.11 S POS TARG 0,-1.5; PATTERN 1 1 Comments: Gain 15, because very high count rate in central object. Brightest pixel may saturate at one of the dither points, but probably not at all of them. ------------------------------------------------------------------------------------------------------------------------------------ 2 ETA-CAR-A WFPC2 IMAGE PC1 F336W ATD-GAIN=15 1 0.8 S POS TARG 0,-1.5; PATTERN 1 2 Comments: Gain 15, because very high count rate in central object. We use two different exposure times in order to get high dynamic range in surrounding ejecta. ------------------------------------------------------------------------------------------------------------------------------------ 3 ETA-CAR-A WFPC2 IMAGE PC1 F255W ATD-GAIN=15 1 0.6 S Comments: Minimal short-wvl observation for comparison with earlier ACS data. Count rate is expected to be high, but not as high as for the other filters. ------------------------------------------------------------------------------------------------------------------------------------ 4 ETA-CAR-A WFPC2 IMAGE PC1 F631N ATD-GAIN=15 1 0.11 S Comments: Minimal red observation, for comparison with many pre-2003 WFPC2(PC) F631N data. Very high count rate in central object. ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ ETA-CAR-A 1 WFPC2 IMAGE PC1 F336W 1 none none none 1 N/A ETA-CAR-A 1 WFPC2 IMAGE PC1 F336W 2 none none none 1 N/A ETA-CAR-A 1 WFPC2 IMAGE PC1 F336W 3 none none none 1 N/A ETA-CAR-A 1 WFPC2 IMAGE PC1 F336W 4 none none none 1 N/A 11291( 3) - 05/14/07 08:22 - [ 10] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ ETA-CAR-A 2 WFPC2 IMAGE PC1 F336W 1 none none none 1 N/A ETA-CAR-A 2 WFPC2 IMAGE PC1 F336W 2 none none none 1 N/A ETA-CAR-A 2 WFPC2 IMAGE PC1 F336W 3 none none none 1 N/A ETA-CAR-A 2 WFPC2 IMAGE PC1 F336W 4 none none none 1 N/A ETA-CAR-A 3 WFPC2 IMAGE PC1 F255W none none none none 1 N/A ETA-CAR-A 4 WFPC2 IMAGE PC1 F631N none none none none 1 N/A 11291( 3) - 05/14/07 08:22 - [ 11] Summary Form for Proposal 11291 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PC1 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BEFORE 01-SEP-2007 00 00 00; POS TARG 0,-1.5; PATTERN 1 1; PATTERN 1 2; AFTER 01 BY 150 D TO 260 D; AFTER 01-JUL-2008 00 00 00; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F336W F255W F631N ------------------------------------------------------------------------------------------------------------------------------------ Target Names ETA-CAR-A ------------------------------------------------------------------------------------------------------------------------------------