6050( 10) - 09/26/95 15:05 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6050 Version: 10 Check-in Date: ********** 1.Proposal Title: Spectroscopic and photometric study of the very low mass triple system LHS 1070 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Cool Stars GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Christoph Leinert Max-Planck-Institut fuer Astronomie CoI: Andrea Richichi Max-Planck-Institut fuer Astronomie N CoI: France Allard University of British Columbia N ------------------------------------------------------------------------------------ 6. Abstract Recently we detected and resolved in the near-infrared two faint components to the nearby low mass star LHS 1070. With their absolute K magnitudes of K_B = 10.4 mag and K_C = 10.8 mag these companions are expected to have masses very close to the hydrogen burning limit of 0.08 M_sun. Since the system is at a distance of only 7.5 pc from the sun, dynamical masses can be determined, and the very low mass companions still are bright enough for detailed study. Thus they provide an excellent if not unique opportunity to better determine the poorly covered transition region from low mass stars to substellar masses. We propose to do so by photometry with the WFPC2 and by spectroscopy with the FOS of all three components of LHS 1070. We want -- to check for substellar masses by searching for the Li 670.8 nm absorption, -- to determine luminosities by photometry and by integrating over spectra, -- to determine effective temperatures from VO and CaH bands, and -- to estimate metallicity and age from Na lines and other spectral features. This should also help to better understand other known very faint objects for which information on mass is not available. ------------------------------------------------------------------------------------ 6050( 10) - 09/26/95 15:05 - [ 2] Observations Description ------------------------ Orbit 1.Accurate positioning is critical for this proposal. Therefore the first orbit is used for an early acquisition with the WFPC2. The same orbit is used to give broadband photometry of the object, complemented by H-Alpha. With overheads of 3 minutes we do not plan for exposures shorter than 1 minute. Example: At V, component "A" has 15.6 mag, and we predict a count of 250 000 in 60s, while for the faintest component "C" (3.5 mag fainter) the count would be 10 000. At B, component "A" has 17.5 mag, "C" is about 4 mag fainter, and the count rates for 8 minutes integration are 64 000 and 1 600, respectively. The remaining 10 minutes left to fill the orbit are used for H-Alpha. With the pixel size of WFPC2 of 0.046 arcsec the components A,B,C will be well separated. Ten orbits are used for spectroscopy. To achieve the scientific goals, S/N ratios of 20-30 are aimed at. Orbits 2-4. Critical peak-up into the 0.3 arcsec aperture with accuracy of 0.04 arcsec requires three orbits, the first for peak-up type A and B, the second for peak-up type C, the third for peak-up type D. The remaining 32 minutes in orbits 3 and 4 will be used for spectroscopy of components "B" and "C" combined with the aperture of 0.9 arcsec at higher S/N ratio. Orbits 5-11. Here, the components "A","B", "C" will be measured separately with gratings F570H and F780H. Example: At 700 nm component "A" has F_Lambda = 10^-14 ergcm^-2s^-1ang^-1. The countrate for grating F780H into the aperture 0.3 arcsec then is about 1.5 counts/s longward of 700 nm. We plan an integration time of 12 min to obtain a total count rate of 1080 (S/N ~ 30). Two orbits (a total of 80 min integration) are used for component "C" to give 740 counts, one orbit for component "B" to give 600 counts. This emphasis is made to be able to see the Lithium absorption if present. Component "A", used as comparison star, always is observed to slightly higher accuracy. Similarly, the remaining three orbits are used for measurements with grating F570H. Real Time Justification ----------------------- Early acquisition by the WFPC2 required in visit 1, since the offsetting from the primary to the faint companions is critical for the spectra to be taken in visit 2. Because of orbital motions in the system, visit 2 should not be later by more than 2 months than visit 1, preferably sooner. We will continue the observations of LHS 1070 in the near- infrared from the ground, in order to know its orbit sufficiently well to allow at least differential predictions of orbital motion for a couple of months ahead for the faint components of this system. Calibration Justification ------------------------- The calibration information provided by the project should be sufficient for our proposal. Additional Comments ------------------- The object is a high proper motion star (LHS coordinates in the literature. We are confident that by reading telescope coordinates during the ground-based infrared observations and by measuring a Schmidt plate taken for this purpuse, we will be able to predict the coordinates to within 1-2 arcsec. This should be well sufficient for the exposure with the PC. However, we want to mention this particularity of the object. ------------------------------------------------------------------------------------ 6050( 10) - 09/26/95 15:05 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS __Diagnosti Email: , ------------------------------------------------------------------------------------ 6050( 10) - 09/26/95 15:05 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 LHS1070 STAR, M V-IV, BROWN RA = 0H 24M 44.40S +/- 0.30S, 2000 V = -45 V=15.42 +/- 0.1 TYPE= M5.5 R-I = 1.78 +/ DWARF DEC = -27D 08' 26.5" +/- 5.0" - 0.1 B-V = 1.98 +/- 0.2 Comments: -- B-V taken from Gliese 866 (M dwarf system with same spectral type) -- remaining information from Gliese- Jahreiss-catalog of nearby stars, to appear in print 1995 -- values given refer to the integrated system (A+B+C). Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) B1995 -0.0036 0.612 0.1328 2 LHS1070-A- STAR, M V-IV, BROWN RA = 0H 24M 44.407S +/- 0.30S, 2000 V = -45 V=15.42 +/- 0.1 TYPE= M5.5 R-I = 1.78 +/ OFFSET DWARF DEC = -27D 08' 37.96" +/- 5.0", - 0.1 B-V = 1.98 +/- 0.2 PLATE-ID=04JL Comments: -- component A is expected to carry most of the flux of the system (A+B+C) at the optical wavelengths. Coordinates were taken from the GASP system since component A should dominate (over B & C) on the plates. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1977.70 -0.0062 0.612 0.1328 3 LHS1070-B STAR, M V-IV, BROWN RA-OFF=-0.0088S +/- 0.01S, DEC- 2000 V = -45 V=17.64 +/- 0.5 TYPE= M7 R-I = 1.97 +/- DWARF OFF=+1.100" +/- 0.02", FROM 2 0.2 B-V = 2.39 +/- 0.4 Comments: -- the brightness and colour information is not known but estimated by extrapolation from the near-infrared observations of relative brightnesses and from the brightnesses of the system (A+B+C). -- offset positions are provisional, to be improved before the observations will happen -- spectral type is a guess 4 LHS1070-C STAR, M V-IV, BROWN RA-OFF=-0.0050S +/- 0.01S, DEC- 2000 V = -45 V=18.44 +/- 0.7 TYPE= M8 R-I = 2.05 +/- DWARF OFF=+1.562" +/- 0.02", FROM 2 0.2 B-V = 2.51 +/- 0.5 Comments: same as for (3) 5 LHS1070-BC STAR, M V-IV, BROWN R = 1.334", PA = 356.05D, FROM 2 2000 V = -45 V=17.40 +/- 0.5 TYPE= M7 R-I = 2.00 +/- DWARF 0.2 B-V = 2.35 +/- 0.5 Comments: -- the brightness, colour and spectral type information is just the combination of values given for components B and C. -- offset positions are provisional, to be improved before the observations will happen -- position to be used for combined observations of B and C 6050( 10) - 09/26/95 15:05 - [ 5] Visit: 01 Visit Requirements: PCS MODE F On Hold Comments: Additional Comments: This visit produces scientific results. At the same time it is used as an early acquisition for visits 2 and 3 (orbits 2-11). Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 LHS1070 WFPC2 IMAGE PC1 F814W 7940 1 10S ------------------------------------------------------------------------------------------------------------------------------------ 2 LHS1070 WFPC2 IMAGE PC1 F675W 6714 1 10S ------------------------------------------------------------------------------------------------------------------------------------ 3 LHS1070 WFPC2 IMAGE PC1 F555W 5407 1 20S ------------------------------------------------------------------------------------------------------------------------------------ 4 LHS1070 WFPC2 IMAGE PC1 F439W 4300 1 350S ------------------------------------------------------------------------------------------------------------------------------------ 5 LHS1070 WFPC2 IMAGE PC1 F656N 6563 1 400S ------------------------------------------------------------------------------------------------------------------------------------ 6 LHS1070 WFPC2 IMAGE PC1 F658N 6590 1 300S ------------------------------------------------------------------------------------------------------------------------------------ 7 LHS1070 WFPC2 IMAGE PC1 F673N 6590 1 200S ------------------------------------------------------------------------------------------------------------------------------------ 6050( 10) - 09/26/95 15:05 - [ 6] Visit: 02 Visit Requirements: PCS MODE F AFTER 1 BY 50D TO 110D ON HOLD FOR 1 On Hold Comments: Waiting for the results of early acquisition from visit 1 Additional Comments: -- This visit is to provide accurate acquisition in several steps on ****** the primary ******* of the triple system. Then measurements on the primary, and by offsetting, on components B and C are performed. Fills orbits 2-11. - - Since there is orbital motion in the system, of the order of 30 degrees per year, visit 2 should follow visit one as soon as possible, in order to have minimum uncertainties in the positions of components B and C relative to A. Also, in order to keep flexibility in the scheduling of visit 2, it would be good to get the WFPC exposures of visit 1 as early as possible during cycle 5. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 LHS1070-A- FOS/RD ACQ/PEA 4.3 MIRROR SEARCH-SIZE-X = 1 4S ONBOARD ACQ FOR 2 OFFSET K 1, SEARCH-SIZE- Y = 3, SCAN- STEP-Y = 1.23 ------------------------------------------------------------------------------------------------------------------------------------ 2 LHS1070-A- FOS/RD ACQ/PEA 1.0 MIRROR SEARCH-SIZE-X = 1 4S ONBOARD ACQ FOR 3 OFFSET K 6, SEARCH-SIZE- Y = 2, SCAN- STEP-X = 0.61, SCAN-STEP-Y = Comments: 0.61 ------------------------------------------------------------------------------------------------------------------------------------ 3 LHS1070-A- FOS/RD ACQ/PEA 0.3 MIRROR SEARCH-SIZE-X = 1 4S ONBOARD ACQ FOR 4 OFFSET K 5, SEARCH-SIZE- Y = 5, SCAN- STEP-X = 0.17, SCAN-STEP-Y = Comments: 0.17 ------------------------------------------------------------------------------------------------------------------------------------ 4 LHS1070-A- FOS/RD ACQ/PEA 0.3 MIRROR SEARCH-SIZE-X = 1 7S ONBOARD ACQ FOR 5-20 OFFSET K 5, SEARCH-SIZE- Y = 5, SCAN- STEP-X = 0.052, SCAN-STEP-Y = Comments: -- the pointing has to be ** very accurate ** 0.052 over orbits nr. 2-15, since B and C are separated only by 0.3"-0.4". Our acquisition has to provide this accuracy and has to actually peak up on the primary star. ------------------------------------------------------------------------------------------------------------------------------------ 5 LHS1070-A- FOS/RD ACCUM 1.0 G570H 1 580S OFFSET ------------------------------------------------------------------------------------------------------------------------------------ 6 LHS1070-BC FOS/RD ACCUM 1.0 G650L 1 600S ------------------------------------------------------------------------------------------------------------------------------------ 7 LHS1070-A- FOS/RD ACCUM 1.0 G650L 1 180S OFFSET ------------------------------------------------------------------------------------------------------------------------------------ 6050( 10) - 09/26/95 15:05 - [ 7] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 8 LHS1070-B FOS/RD ACCUM 0.3 G570H 1 1910S ------------------------------------------------------------------------------------------------------------------------------------ 9 LHS1070-C FOS/RD ACCUM 0.3 G570H 1 2370S ------------------------------------------------------------------------------------------------------------------------------------ 10 LHS1070-C FOS/RD ACCUM 0.3 G570H 1 2370S ------------------------------------------------------------------------------------------------------------------------------------ 11 LHS1070-A- FOS/RD ACCUM 1.0 G780H 1 570S OFFSET ------------------------------------------------------------------------------------------------------------------------------------ 12 LHS1070-C FOS/RD ACCUM 0.3 G780H 1 1500S ------------------------------------------------------------------------------------------------------------------------------------ 13 LHS1070-C FOS/RD ACCUM 0.3 G780H 1 2370S ------------------------------------------------------------------------------------------------------------------------------------ 14 LHS1070-B FOS/RD ACCUM 0.3 G780H 1 1980S ------------------------------------------------------------------------------------------------------------------------------------ 15 LHS1070-B FOS/RD IMAGE 4.3 MIRROR SUB-STEP=4 Y- 1 84S SAME POS AS 14 OFFSET=0 Y- SPACE=16.76 Y- SIZE=21 STEP- TIME=1.0 ------------------------------------------------------------------------------------------------------------------------------------ 16 LHS1070-B FOS/RD ACCUM 0.3 G650L 1 550S Comments: -- Concerning "REUSE TARGET OFFSETS": Two minutes have been reserved here to allow for the necessary small angle movements. The programme added them to exposure two, from where they should be taken again.*** ------------------------------------------------------------------------------------------------------------------------------------ 17 LHS1070-C FOS/RD ACCUM 0.3 G650L 1 1020S ------------------------------------------------------------------------------------------------------------------------------------ 18 LHS1070-BC FOS/RD ACCUM 1.0 G780H 1 830S ------------------------------------------------------------------------------------------------------------------------------------ 19 LHS1070-BC FOS/RD ACCUM 1.0 G570H 1 830S ------------------------------------------------------------------------------------------------------------------------------------ 20 LHS1070-B FOS/RD IMAGE 4.3 MIRROR SUB-STEP=4 Y- 1 84S SAME POS AS 14 OFFSET=0 Y- SPACE=16.76 Y- SIZE=21 STEP- TIME=1.0 ------------------------------------------------------------------------------------------------------------------------------------ 6050( 10) - 09/26/95 15:05 - [ 8] Summary Form for Proposal 6050 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 FOS/RD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SEARCH-SIZE-X = 1 SEARCH-SIZE-Y = 3 SCAN-STEP-Y = 1.23 SCAN-STEP-Y = 0.61 SCAN-STEP-Y = 0.17 SCAN-STEP-Y = 0.052 SUB-STEP=4 Y-OFFSET=0 Y-SPACE=16.76 Y-SIZE=21 STEP-TIME=1.0 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Cool Stars ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PCS MODE F PCS MODE F AFTER 1 BY 50D TO 110D ON HOLD FOR 1 ONBOARD ACQ FOR 2 ONBOARD ACQ FOR 3 ONBOARD ACQ FOR 4 ONBOARD ACQ FOR 5-20 SAME POS AS 14 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F814W F675W F555W F439W F656N F658N F673N MIRROR G570H G650L G780H ------------------------------------------------------------------------------------------------------------------------------------ Target Names LHS1070 LHS1070-A-OFFSET LHS1070-BC LHS1070-B LHS1070-C ------------------------------------------------------------------------------------------------------------------------------------