Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5329 Report Date: 18-Jul-95:17:09 Version: ********** Check-in Date: ********** 1.Proposal Title: COORDINATED OBSERVATIONS OF NEPTUNE'S AEROSOLS: TEMPORAL, VERTICAL, AND HORIZONTAL VARIABLILTY CYCLE4 MEDIUM ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID SOLAR SYSTEM GO 1 Long Term yrs Sub Category GIANT PLANETS ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Heidi B Hammel 2630 USA 617-253-7568 ------------------------------------------------------------------------------------ 7. Abstract We propose to obtain images of Neptune with WF/PC2 at wavelengths from 3327 to 8940 A, along with complementary groundbased observations: visible and IR imaging at the U.H. 2.2-m (HI), and Stromgren b and y photometry and methane-band spectra at Lowell Observatory (AZ). The data will be used to: model the current vertical aerosol structure by measuring the general center-to-limb behavior versus latitude; study the wavelength-dependent reflectivity of discrete features; measure the current distribution and number of discrete features; image the Great Dark Spot to provide a better estimate of its lifetime; and provide new measurements of atmospheric winds as a function of latitude. By being combined with groundbased data, HST data will be tied into the groundbased series of Neptune data taken by PI Hammel for the past 7 years and Co-I Lockwood for over 20 years. Simultaneous groundbased data were also obtained during the 1989 Voyager Encounter with Neptune; thus the observations proposed here will directly link HST Neptune observations to those obtained by Voyager 2. HST images will provide critical high-resolution observations, which along with the ground-based data will lead to unprecedented understanding of the temporal variations of Neptune's vertical aerosol structure and horizontal dynamics. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 4.83 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: WF/PC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5329 PI: Heidi B Hammel Proposal Title: COORDINATED OBSERVATIONS OF NEPTUNE'S AEROSOLS: TEMPORAL, VERTICAL, AND HORIZONTAL VARIABLILTY CYCLE4 MEDIUM ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Heidi B Hammel 2630 USA Wes Lockwood 2540 USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. (General descript here, detailed request in section 2.....) We request a total of 54 exposures. They should be divided into three blocks (for a total of 18 exposures per block). The purpose of a BLOCK is to take a snapshot of all longitudes on Neptune at a given point in time. The rotation period of Neptune varies with latitude, but typically is roughly 18 hours for the brightest cloud features. Therefore, to sample all longitudes, we need a snapshot at time X, a snapshot at time X+6 hours, and a snapshot at time X+12 hours. These separation times (6 hours and 12 hours) are approximate. The range of suitable separation times is about 5 to about 7 hours. Because we want to image Neptune at many wavelengths, each snapshot referred to above is actually going to be a SET of six exposures, one through each of six different filters. Hence a block is composed of three sets of six exposures (18 total). Every set is identical to every other set: simply acquire Neptune, and step through the six filters. We know from ground-based observations that variations in the atmosphere of Neptune occur on many timescales. The purpose of obtaining two more blocks is to try to characterize the time variability. The separations between the additional blocks is NOT critical; it is simply a recommendation to capture the most likely timescales of variation. Block 1 -- 18 exposures as described above, i.e. three sets of six exposures, each set roughly 6 hours after the previous set -- should be obtained at the first available time. Block 2 (18 exposures as described above) should start roughly a week after block 1. The precise start time of block 2 is NOT critical, but should be more than four days after block 1. Block 3 (18 exposures as described above) should start roughly fours weeks after block 1 (roughly a month). The precise start time of block 3 is NOT critical, but should be more than 10 days after block 2. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. Neptune's disk subtends at most 2.3 arcsec. The type of structure we want to resolve on Neptune (features and center-to-limb variations) typically have sizes corresponding to fractions of an arcsecond. Center-to-limb variations, in particular, are very dependent on the seeing. The highest contrast features have been resolved from the ground, and there is a rich history of groundbased observation. We propose to supplement the long-term groundbased data set with a series of very high resolution images. Page 3 ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. We will require special timing requirements to (1) image all longitudes on the planet, and (2) characterize the temporal variability of cloud structure. To satisfy the first condition, all six exposures in a set must be as close together in time as possible (but order is not important), and we will require three sets, one each at three rotational phases (three sets is a "block"). To address the second question, we will require two more series of observations at selected times after the first series. More details are provided in "Question 3 - Description of proposed observations." Also, we are requesting time near Neptune opposition to maximize the time available for obtaining the coordinating groundbased observations. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. We will be coordinating the HST observations with groundbased observing at several sites. This will minimize the amount of HST time needed to characterize the atmosphere, and will provide more detailed understanding of Neptune by adding wavelengths which are not accessible to HST (e.g. the intermediate methane band at 7270 A, and infrared wavelengths). Some funds will be requested for the PI to make the observations, and for minimal support of the data analysis. ------------------------------------------------------------------------------------ 9. Description of previous HST work. PI has never had HST time before. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). Existing computing facilities at MIT will be used for the data analysis. The computers, all linked through an ethernet network, include a DEC 5000, several smaller DEC workstations, numerous Macintosh workstations, and a variety of peripherals (including several laser printers, tape drives, optical disks, etc.). Supported software packages include IRAF and IDL. The MIT computer system provides access to the Internet and SPAN communications networks, with gateways to BITNET. MIT has a strong tradition of undergraduate participation in research, making funds available for support. There will likely be one or two undergraduates working with the PI on the project. Some graduate student assistance may also be desired. The PI's MIT position is a research staff appointment, so there are no anticipated conflicts with a teaching load. ------------------------------------------------------------------------------------ 11. Address Information Name: Heidi B Hammel Category: PI Institution: 2630 Address: MIT 54-416 City: Cambridge State: MA Zip Code: 02139 Country: USA Telephone: 617-253-7568 Telex (or e-mail): hbh@astron.mit.edu ------------------------------------------------------------------------------------ TARGET LIST b)Solar System Targets ID = 5329 [ 4] ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 | TARGET NAME: NEPTUNE ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: PLANET NEPTUNE ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = NEPTUNE | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF NEPTUNE BETWEEN 320 40 | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |V = 8.8 | THE WINDOW AROUND OPPOSITION (OLG 2 |F(3327) = 1.50 E-12 | NEAR 0) IS REQUESTED TO COORDINATE 3 |F(4089) = 3.88 E-12 | WITH GROUNDBASED OBSERVATIONS. IF 4 |F(4682) = 3.51 E-12 | THIS WINDOW IS STILL UNAVAILABLE 5 |F(5454) = 2.66 E-12 | AFTER HST REFURBISHMENT, THEN WE CAN 6 |F(6265) = 3.77 E-13 | RELAX THE CONSTRAINT SOMEWHAT. 7 |F(8940) = 9.98 E-14 | CONTACT PI H. B. HAMMEL, AT MIT. | ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5329 [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 5.01 DEFINE NEPTUNE WFPC2 IMAGE PC1 F336W 1 140S 1000 2 1 GROUP 5.01-5.06 NO SET GAP ------------------------------------------------------------------------------------------------------------------------------------ 5.02 DEFINE NEPTUNE WFPC2 IMAGE PC1 F410M 1 70S 990 3 1 SET ------------------------------------------------------------------------------------------------------------------------------------ 5.03 DEFINE NEPTUNE WFPC2 IMAGE PC1 F467M 1 50S 1100 4 1 SET ------------------------------------------------------------------------------------------------------------------------------------ 5.04 DEFINE NEPTUNE WFPC2 IMAGE PC1 F547M 1 14S 1700 5 1 SET ------------------------------------------------------------------------------------------------------------------------------------ 5.05 DEFINE NEPTUNE WFPC2 IMAGE FQCH4N1 FQCH4N15 6211 1 700S 1100 6 1 SET 5 ------------------------------------------------------------------------------------------------------------------------------------ 5.06 DEFINE NEPTUNE WFPC2 IMAGE FQCH4P1 FQCH4P15 8922 1 1400S 430 7 1 SET 5 ------------------------------------------------------------------------------------------------------------------------------------ 11.01 USE SET CYCLE 4 / 5.01 - 33.01 ------------------------------------------------------------------------------------------------------------------------------------ 12.01 USE SET AFTER 11.01 BY 6 H +/- 2 H ------------------------------------------------------------------------------------------------------------------------------------ 13.01 USE SET AFTER 11.01 BY 12 H +/- 2 H ------------------------------------------------------------------------------------------------------------------------------------ 21.01 USE SET AFTER 11.01 BY 7 D +/- 3 D ------------------------------------------------------------------------------------------------------------------------------------ 22.01 USE SET AFTER 21.01 BY 6 H +/- 2 H ------------------------------------------------------------------------------------------------------------------------------------ 23.01 USE SET AFTER 21.01 BY 12 H +/- 2 H ------------------------------------------------------------------------------------------------------------------------------------ 31.01 USE SET AFTER 11.01 BY 28 D +/- 8 D ------------------------------------------------------------------------------------------------------------------------------------ 32.01 USE SET AFTER 31.01 BY 6 H +/- 2 H ------------------------------------------------------------------------------------------------------------------------------------ 33.01 USE SET AFTER 31.01 BY 12 H +/- 2 H Comments: WE HAVE TIMING REQUIREMENTS TO (1) IMAGE ALL NEPTUNE LONGITUDES, AND (2) STUDY TEMPORAL VARIATIONS. IF HST CAN'T MEET THE REQUIREMENTS, WE CAN RELAX THE CONSTRAINTS A BIT. CONTACT PI H. B. HAMMEL, AT MIT. ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5329 [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 4.83 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category SOLAR SYSTEM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category GIANT PLANETS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GROUP 5.01-5.06 NO GAP CYCLE 4 / 5.01 - 33.01; AFTER 11.01 BY 6 H +/- 2 H AFTER 11.01 BY 12 H +/- 2 H AFTER 11.01 BY 7 D +/- 3 D AFTER 21.01 BY 6 H +/- 2 H AFTER 21.01 BY 12 H +/- 2 H AFTER 11.01 BY 28 D +/- 8 D AFTER 31.01 BY 6 H +/- 2 H AFTER 31.01 BY 12 H +/- 2 H ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F336W F410M F467M F547M FQCH4N15 FQCH4P15 ------------------------------------------------------------------------------------------------------------------------------------ Target Names NEPTUNE ------------------------------------------------------------------------------------------------------------------------------------