Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 2941c Report Date: 09-May-96:17:38 Version: ********** Check-in Date: ********** 1.Proposal Title: HIGH SPEED ASTROMETRY - A SEARCH FOR PLANETARY COMPANIONS TO LOW-MASS STARS PART THREE ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID SOLAR SYSTEM GTO/AST 2 Long Term yrs Sub Category ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Dr. William H. Jefferys UNIVERSITY OF TEXAS USA (512)471-3000 PROFESSOR ------------------------------------------------------------------------------------ 7. Abstract We propose to test the hypothesis that jupiter-like planets are formed at distances from the primary dictated by the 'freezing' temperature of the volatiles which comprise jovian planets. Predicted periods for jovian planets orbiting this sample of very late-type, low-mass stars range from 70 to 160 days. We shall monitor the positions of these nearby late-M stars with a time-resolution of 4 to 10 days in an attempt to detect positional perturbations caused by possible jovian companions. Detection limits for these proposed targets lie between 0.4 and one Jupiter mass. ------------------------------------------------------------------------------------ 8. Scientific Key Words: FINE GUIDANCE SENSORS, FGS, STELLAR COMPANIONS, EXTRASOLAR PLANETS ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 35.00 par: 0 10. Num targs pri: 6 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: FGS ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 2941c PI: Dr. William H. Jefferys Proposal Title: HIGH SPEED ASTROMETRY - A SEARCH FOR PLANETARY COMPANIONS TO LOW-MASS STARS PART THREE ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Dr. William H. Jefferys UNIVERSITY OF TEXAS USA Dr. George F. Benedict UNIVERSITY OF TEXAS USA Dr. Raynor L. Duncombe UNIVERSITY OF TEXAS USA Dr. Paul D. Hemenway UNIVERSITY OF TEXAS USA Dr. Peter S. Shelus UNIVERSITY OF TEXAS USA Dr. Otto G. Franz LOWELL OBSERVATORY USA Dr. Laurence W. Fredrick UNIVERSITY OF VIRGINIA USA Dr. William F. Van Altena YALE UNIVERSITY USA ------------------------------------------------------------------------------------ 2. Scientific Justification. Are planetary systems prevelent? Can we derive an observing strategy which will increase the likelihood of answering this question? Assumptions: 1. The processes which resulted in our Solar System are not unique. 2. A star's pre-planetary nebula scales ( in temperature ) as the luminosity ( bolometric absolute magnitude ) of the central star. 3. Looking ( astrometrically ) for planets implies looking for gas giants orbiting low-mass stars ( most favorable mass- ratio ). 4. Gas giants form at about the same temperature in the pre-planetray nebula and hence at a predictable distance from the central star. 5. The distance between a gas giant and the central star scales as 5.2*sqrt(Lstar/Lsun), where 5.2 AU represents the Sun - Jupiter separation. Choosing the lowest-mass, nearest stars known to be either wide binaries or single stars, one can calculate the period of a Jupiter-mass planet orbiting each at a distance calculated to provide the proper formation temperature. These periods range from 74 to 155 days. Values for the periods are quite uncertain since neither bolometric corrections nor masses for late-M stars are well known. Six primary objects will be observed. Should HST efficiency be greater than predicted, the two secondary objects will be observed. Black and Scargle ( Ap. J. 263:854. 1982 ) recommend a maximum observing interval of one-half the predicted period. Since we do not know the period of a postulated gas giant, we have chosen to take 25 observations over somewhat more than one predicted period, to provide adequate coverage. Thus, observing intervals range from 4 to 8 days. Gatewood et. al. ( Icarus 41:205. 1980 ) have devised an algorithm for calculating the minimum detectable mass of an unseen companion. This was used to obtain the results below for the Primary Targets. PARAMETER PROXIMA BARNARD W359 L726-8A L726-8B R248 --------- ------- -- ----- ---- ------- ------- ---- parallax 0.757 0.553 0.428 0.370 0.370 0.314 vmag 11.22 9.54 13.55 12.95 12.50 12.29 abs. bol. mag. 11.7 10.9 12.2 11.76 12.14 12.0 Sp type dM5e M5 M8e M6e M6e M6e stellar mass/solar 0.10 0.15 0.07 0.12 0.11 0.07 lum/solar 0.0016 0.0033 0.001 0.001 0.001 0.001 gg r in AU 0.21 0.30 0.16 0.17 0.17 0.16 gg P in days 106 153 88 82 82 88 Number of obs 30 30 30 30 30 30 obs spacing in days 5 8 4 4 4 4 Minimum detectable mass/solar 0.00036 0.00064 0.0007 0.001 0.001 0.0008 __________________________________ gg r = gas giant/primary seperation gg P = gas giant orbital period ------------------------------------------------------------------------------------ 3. Description of proposed observations. Acquire guide stars in the FGS units selected for guiding. Measure target, then reference stars, then target. Observations will be spaced 4 to 10 days over a time span of 100 to 250 days, depending on the target. Use FGS unit designated as Astrometry Prime. Cycle 0 = Exposures 13, 23 Cycle 1 = Exposures 13, 23, 33 ,45, 53, 63 Cycle 2 = Exposures 63 Page 3 ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The minimum detectable mass depends directly on the accuracy of the positional measurements. Ground-based accuracies rarely exceed 50 milliarcseconds (mas). The assumed 2 mas accuracy of HST should let us detect 25 times less massive companions than from the ground. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. Data reduction will be performed using the ADRS within the SDAS system at STScI with other analyses being performed in Austin. The data will be put into the SDAS format for analysis using the GAUSS module. ------------------------------------------------------------------------------------ 13. "High-Speed" Astrometry will be carried out on 6-8 low-mass stars in an effort to detect positional perturbations due to jovian planets. We assume that such planets will lie close to these low luminosity stars, and, hence, have fairly short orbital periods. Observations will be spaced 4 to 8 days apart. ------------------------------------------------------------------------------------ 11. Address Information Name: JEFFERYS Category: PI Institution: Address: City: State: Zip Code: Country: Telephone: Telex (or e-mail): ------------------------------------------------------------------------------------ Name: GEORGE F. BENEDICT Category: CON Institution: Address: DEPARTMENT OF ASTRONOMY City: AUSTIN State: TX Zip Code: 78712 Country: USA Telephone: (512)471-3448 Telex (or e-mail): ------------------------------------------------------------------------------------ Name: WILLIAM H. JEFFERYS Category: PI Institution: UNIVERSITY OF TEXAS Address: DEPARTMENT OF ASTRONOMY City: AUSTIN State: TX Zip Code: 78712 Country: USA Telephone: (512)471-1455 Telex (or e-mail): TEXASTRO ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 2941c [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 29 BARNARDS- HIGHEST PROPER MOTION RA = 17H 55M 20.94S +/- 2", 1950.0 1 V = 9.54 +/- 0.02 STAR STAR DEC = +4D 39' 21.40" +/- 2" ------------------------------------------------------------------------------------------------------------------------------------ 30 BARNARD-GSC- REFERENCE STAR FOR RA = 269.47687D +/- 0.0003D, 2000.0 1 V = 13.26 +/- 0.6 1-REF BARNARDS STAR DEC = +4.680570D +/- 0.0003D ------------------------------------------------------------------------------------------------------------------------------------ 31 BARNARD-75- REFERENCE STAR FOR RA = 269.436264D +/- 2000.0 1 V = 16.84 +/- 0.6 REF BARNARDS STAR 0.0003D, DEC = +4.690059D +/- 0.0003D ------------------------------------------------------------------------------------------------------------------------------------ 32 BARNARD-81- REFERENCE STAR FOR RA = 269.437087D +/- 2000.0 1 V = 15.5 +/- 0.6 REF BARNARDS STAR 0.0003D, DEC = +4.679343D +/- 0.0003D ------------------------------------------------------------------------------------------------------------------------------------ 33 BARNARD-90- REFERENCE STAR FOR RA = 269.42924D +/- 0.0003D, 2000.0 1 V = 15.5 +/- 0.6 REF BARNARDS STAR DEC = +4.666314D +/- 0.0003D ------------------------------------------------------------------------------------------------------------------------------------ 34 BARNARD-GSC- REFERENCE STAR FOR RA = 269.456590D +/- 2000.0 1 V = 14.52 +/- 0.6 2-REF BARNARDS STAR 0.0003D, DEC = +4.706910D +/- 0.0003D ------------------------------------------------------------------------------------------------------------------------------------ 35 BARNARD-93- REFERENCE STAR FOR RA = 269.457916D +/- 2000.0 1 V = 16.54 +/- 0.6 REF BARNARDS STAR 0.0003D, DEC = +4.674444D +/- 0.0003D ------------------------------------------------------------------------------------------------------------------------------------ 36 BARNARD-GSC- REFERENCE STAR FOR RA = 269.466480D +/- 2000.0 1 V = 11.18 +/- 0.6 3-REF BARNARDS STAR 0.0003D, DEC = +4.705630D +/- 0.0003D ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 2941c [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 20 DEFINE BARNARDS- FGS POS PRIME F583W DATA-RATE=32 1 10S 10 1 1 SEQ 20-26 NON-INT SEQ21 STAR GUID TOL 0.007" Comments: AVOID TERMINATOR CROSSING ------------------------------------------------------------------------------------------------------------------------------------ 20.5 DEFINE BARNARD-GSC ^ ^ ^ ^ ^ ^ 52S ^ ^ SEQ21 -1-REF ------------------------------------------------------------------------------------------------------------------------------------ 21 DEFINE BARNARD-75- ^ ^ ^ ^ ^ ^ ^ ^ ^ DO FOR TARG 31-33 SEQ21 REF Comments: OBSERVE ONLY THOSE REFERENCE STARS WITHIN THE ASTROMETRY PICKLE ------------------------------------------------------------------------------------------------------------------------------------ 22 DEFINE BARNARDS- ^ ^ ^ ^ ^ ^ 10S ^ ^ SEQ21 STAR ------------------------------------------------------------------------------------------------------------------------------------ 23 DEFINE BARNARD-GSC ^ ^ ^ ^ ^ ^ 52S ^ ^ SEQ21 -1-REF ------------------------------------------------------------------------------------------------------------------------------------ 24 DEFINE BARNARD-GSC ^ ^ ^ ^ ^ ^ ^ ^ ^ DO FOR TARG 34-36 SEQ21 -2-REF Comments: OBSERVE ONLY THOSE REFERENCE STARS WITHIN THE ASTROMETRY PICKLE ------------------------------------------------------------------------------------------------------------------------------------ 25 DEFINE BARNARD-GSC ^ ^ ^ ^ ^ ^ ^ ^ ^ SEQ21 -1-REF ------------------------------------------------------------------------------------------------------------------------------------ 26 DEFINE BARNARDS- ^ ^ ^ ^ ^ ^ 10S ^ ^ SEQ21 STAR ------------------------------------------------------------------------------------------------------------------------------------ 27 USE AT 4 -FEB-93 +/- SEQ21 4D REPEAT 27 EVERY 16D +/- 2D FOR 16 MORE TIMES Comments: BREAK IN SERIES AVOIDS HST SUN CYCLE 2 CONSTRAINTS ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 2941c [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FGS ^ ------------------------------------------------------------------------------------------------------------------------------------ Opmodes POS ^ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters DATA-RATE=32 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GTO/AST ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 35.00 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category SOLAR SYSTEM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements SEQ 20-26 NON-INT; GUID TOL 0.007" DO FOR TARG 31-33; DO FOR TARG 34-36; AT 4 -FEB-93 +/- 4D; REPEAT 27 EVERY 16D +/- 2D FOR 16 MORE TIMES; CYCLE 2; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F583W ^ ------------------------------------------------------------------------------------------------------------------------------------ Target Names BARNARDS-STAR BARNARD-GSC-1-REF BARNARD-75-REF BARNARD-81-REF BARNARD-90-REF BARNARD-GSC-2-REF BARNARD-93-REF BARNARD-GSC-3-REF ------------------------------------------------------------------------------------------------------------------------------------