6338( 16) - 03/04/96 15:45 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6338 Version: 16 Check-in Date: 04-Mar-1996 15:38:24 1.Proposal Title: Colors, Parallax and Orbit of GL229B ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Cool Stars GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Shrinivas R. Kulkarni California Institute of Technology CoI: Ben R. Oppenheimer California Institute of Technology N CoI: Keith Matthews California Institute of Technology N CoI: Christopher J. Burrows Space Telescope Science Institute Y CoI: David A. Golimowski Johns Hopkins University N CoI: Samuel T. Durrance Johns Hopkins University N CoI: Tadashi Nakajima California Institute of Technology N ------------------------------------------------------------------------------------ 6. Abstract Recently we discovered a low luminosity, cool proper-motion companion to the nearby star GL 229. We see strong absorption features in the companion's H- and K-band spectra that resemble those of Jupiter and that are usually ascribed to methane. From chemical thermodynamics, we know that carbon mainly resides in methane when the temperature is below 1000 K. The totality of the data is consistent with a 20 Jupiter mass object orbiting GL 229 at 7.6 arcsec (44 AU). This is the first detection of such a cool condensed object. We propose HST observations to determine the parallax of the object, which is essential for interpreting the photometric data, and to search for other companions that may be fainter or closer to the main star. ------------------------------------------------------------------------------------ 6338( 16) - 03/04/96 15:45 - [ 2] Observations Description ------------------------ Scientific Justification For the past three years, we have conducted a search for faint companions to nearby stars using the Johns Hopkins University's Adaptive Optics Coronagraph (AOC; Golimowski et al. 1992) and the Palomar 60- inch telescope. Since last year, our search has concentrated on a sample of stars whose presumed age (based on kinematics or chromospheric/coronal activity) is less than one billion years. We have detected a common-proper- motion companion to the star GL 229, a M1 star at 5.7 pc distance. The broad- band spectrum of the companion is unique: it is extremely red below 1 micron, but quite blue around 1 micron. The inferred luminosity is 4 E-6 Lsun, the smallest for any known condensed object. Near-IR (1-2 micron) spectroscopy reveals deep absorption features in the H and K bands similar to those seen in Jupiter's reflected spectrum. These features are attributed to methane. No known star exhibits methane features. Such features are consistent with the prediction of Tsuji (1964) that most of the carbon resides in methane once the temperature falls below 1000 K. This prediction agrees well with the effective temperature deduced from broad-band photometry if it is assumed that the companion has a radius similar to brown dwarfs and Jupiter (0.1 R_sun) and is located at the distance of GL 229. These two assumptions are reasonable, but the very peculiar broad-band spectrum of the object which peaks at 1 micron is hard to reconcile with such a low effective temperature. We propose HST observations to answer the following questions: a) What is the parallax of GL 229B? An independent determination of the parallax will settle the issue of distance without any assumptions. We view this as a very important objective. b) Are there other companions closer to the star? Our ground-based images are affected by atmospheric seeing. Consequently, our ability to detect faint companions within 4 arcseconds of the main star is considerably diminished. The presently available radial velocity data (Butler and Marcy) are too coarse to constrain the absence of other companions. c) Are there fainter companions? HST can achieve a sensitivity of at least 5 mags over our current data. d) Is there any reflected light? If GL 229B is a brown dwarf with the usual radius then the reflected light from the main star should be negligible. However, there are hints in our optical spectrum of GL 229B that there is some emission with an M1 spectrum. If so, the object has to be surrounded by a dust cloud of a large radius. Observations in the red and visual bands (bands at which we have yet to detect the object) would settle this issue. Visit 1 ------- Line 10 is designed to give 4 unsaturated images of GL 229A. F1042M is the only filter that will allow this, while also allowing a good astrometric measurement of GL 229B in a long exposure. This will tie it astrometrically to the results for GL 229B that are obtained in lines 20-21. 4 images are needed in order to average pointing variations somewhat, and to allow removal of cosmic ray and hot pixel contamination. No other sources are expected to be visible in this set of exposures. The offsets are supposed to be along the CCD row/column directions. Lines 20-21 are designed to give an astrometric position for GL 229B. Two exposures are taken at the diagonally opposite corners of the 5x5 pixel box defined by the scan performed in line 10. A number of background sources will also be visible in this frame, allowing GL229B to be tied directly to the external field. The PA of GL 229B is 163 degrees from GL229A. The orient requirements are designed to avoid the saturated columns from A, the spider diffraction spike directions, and the horizointal smearing direction on the CCDs. Lines 10-21 when repeated on the second visit (after 6 months) will provide parallax information for both GL 229B, and confirm the parallax of GL 229A. The same sequence on Visit 3 (one year after visit 1) will provide an independent measurement of the pair's proper motion, and begin to search for orbital motion of GL 229B. Line 30-31 are designed to give crude photometry on GL 229A through F675W. The star will be saturated, but not badly, so we expect to be able to get photometry at the 5-10% level for comparison with the photometry on GL 229B (in case there is a significant scattered light component). Line 31 is offset for hot pixel and CR-rejection purposes. Lines 40 -41 are designed to begin the search for other companions in the region that would be covered by the bleed in the longer exposures following. Lines 50-52 are three long, mutually offset exposures that will give the first R-band measurement of GL 229B. If GL 229B is detected, it will raise the likelihood that a significant portion of the detected light may be scattered light from the primary star. The long exposures will also extend the limiting magnitude for detection of other companions to 5 magnitudes greater the present ground- based limit. Line 60-61, 70-71 and 80-82 repeat the philosophy of lines 30-52 for filter F814W. Again, the three long, mutually offset exposures that will give accurate photometry on GL 229B, and detect other companions up to 5 magnitudes fainter. Visit 2 ------- Obviously what we do here will depend on the results of Visit 1. We attempt a detection in V and repeat the astrometry (for parallax). Visit 3 ------- This just repeats the astrometry (for proper motion, and for orbital motion). Real Time Justification ----------------------- None Calibration Justification ------------------------- None Additional Comments ------------------- >From the Gliese Catalog: Gl 229 06 08 28 -21 50.6 0.737 190.2 13 - 20 Right ascension (B1950.0) 22 - 29 Declination (B1950.0) 31 - 36 Total proper motion (arcseconds per year) 38 - 42 Direction angle of proper motion + 5.2 M1 Ve 8.14 44 - 49 Radial velocity (km/sec) 55 - 66 Spectral type or color class 68 - 73 Apparent magnitude +1.50 +1.23 +0.82 76 - 80 B-V color 83 - 87 U-B color 90 - 94 R-I color (Kron's system) 1749 067 97 - 101 Trigonometric parallax (F5.4) 102 - 105 Standard error of trig. parallax (F4.4) 9.35 a 118 - 122 Absolute visual magnitude, M(V) 125 Quality of absolute magnitude a s.e. < 0.10 mag + 12 - 12 - 12 128 - 131 U space velocity in the galactic plane to the galactic center 133 - 136 V in the galactic plane and in the direction of galactic rotation 138 - 141 W perpendicular to the plane and towards the north galactic pole 42581 BD-21 1377 1827 V471 143 - 148 HD number 150 - 161 Durchmusterung number BD : Bonner Durchmusterung 163 - 171 Giclas number 173 - 177 LHS number ------------------------------------------------------------------------------------ 6338( 16) - 03/04/96 15:45 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6338( 16) - 03/04/96 15:45 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD42581 STAR RA=06H 10M 34.617S +/- .01S, J2000 V = 5.2 V = 8.13+/-0.01 DEC=-21D 51' 53.51" +/- 0.30" Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J2000 -0.00927 -0.723 0.169 6338( 16) - 03/04/96 15:45 - [ 5] Visit: 01 Visit Requirements: ORIENT 328D TO 333D 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 HD42581 WFPC2 IMAGE PC1 F1042M CR- 1 1.6S SPATIAL SCAN 1 SPLIT=NO,SCAN- READ=ALL,READ=Y ES,ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 20 HD42581 WFPC2 IMAGE PC1 F1042M CR- 1 300S SPLIT=NO,READ=Y ES,ATD- GAIN=7,CLOCKS=Y ES ------------------------------------------------------------------------------------------------------------------------------------ 21 HD42581 WFPC2 IMAGE PC1 F1042M CR- 1 300S POS TARG 0.2275, 0.2275 SPLIT=NO,READ=Y ES,ATD- GAIN=7,CLOCKS=Y ES ------------------------------------------------------------------------------------------------------------------------------------ 30 HD42581 WFPC2 IMAGE PC1 F814W CR- 1 0.11S SPLIT=NO,READ=Y ES,ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 31 HD42581 WFPC2 IMAGE PC1 F814W CR- 1 0.11S POS TARG 0.2275, 0.2275 SPLIT=NO,READ=Y ES,ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 40 HD42581 WFPC2 IMAGE PC1 F814W CR- 1 5S SPLIT=NO,READ=Y ES,ATD- GAIN=15,CLOCKS= YES ------------------------------------------------------------------------------------------------------------------------------------ 41 HD42581 WFPC2 IMAGE PC1 F814W CR- 1 5S POS TARG 0.2275, 0.2275 SPLIT=NO,READ=Y ES,ATD- GAIN=15,CLOCKS= YES ------------------------------------------------------------------------------------------------------------------------------------ 50 HD42581 WFPC2 IMAGE PC1 F814W CR- 1 400S SPLIT=NO,READ=Y ES,ATD- GAIN=7,CLOCKS=Y ES ------------------------------------------------------------------------------------------------------------------------------------ 6338( 16) - 03/04/96 15:45 - [ 6] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 51 HD42581 WFPC2 IMAGE PC1 F814W CR- 1 400S POS TARG 0.2275, 0.2275 SPLIT=NO,READ=Y ES,ATD- GAIN=7,CLOCKS=Y ES ------------------------------------------------------------------------------------------------------------------------------------ 52 HD42581 WFPC2 IMAGE PC1 F675W CR- 1 500S SPLIT=NO,READ=Y ES,ATD- GAIN=7,CLOCKS=Y ES ------------------------------------------------------------------------------------------------------------------------------------ 6338( 16) - 03/04/96 15:45 - [ 7] Visit: 02 Visit Requirements: ORIENT 148D TO 148D AFTER 01 BY 175D TO 198D 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 HD42581 WFPC2 IMAGE PC1 F1042M CR- 1 1.6S SPLIT=NO,READ=Y ES,ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 20 HD42581 WFPC2 IMAGE PC1 F1042M CR- 1 300S SPLIT=NO,READ=Y ES,ATD- GAIN=7,CLOCKS=Y ES ------------------------------------------------------------------------------------------------------------------------------------ 30 HD42581 WFPC2 IMAGE PC1 F814W CR- 1 400S SPLIT=NO,READ=Y ES,ATD- GAIN=7,CLOCKS=Y ES ------------------------------------------------------------------------------------------------------------------------------------ 40 HD42581 WFPC2 IMAGE PC1 F1042M CR- 1 1.6S POS TARG 0.2275, 0.2275 SPLIT=NO,READ=Y ES,ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 50 HD42581 WFPC2 IMAGE PC1 F1042M CR- 1 300S POS TARG 0.2275, 0.2275 SPLIT=NO,READ=Y ES,ATD- GAIN=7,CLOCKS=Y ES ------------------------------------------------------------------------------------------------------------------------------------ 60 HD42581 WFPC2 IMAGE PC1 F814W CR- 1 400S POS TARG 0.2275, 0.2275 SPLIT=NO,READ=Y ES,ATD- GAIN=7,CLOCKS=Y ES ------------------------------------------------------------------------------------------------------------------------------------ 6338( 16) - 03/04/96 15:45 - [ 8] Visit: 03 Visit Requirements: ORIENT 328D TO 328D BETWEEN 9-NOV-1996 AND 23-NOV-1996 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 HD42581 WFPC2 IMAGE PC1 F1042M CR- 1 1.6S SPATIAL SCAN 1 SPLIT=NO,SCAN- READ=ALL,READ=Y ES,ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ 20 HD42581 WFPC2 IMAGE PC1 F1042M CR- 1 300S SPLIT=NO,READ=Y ES,ATD- GAIN=7,CLOCKS=Y ES ------------------------------------------------------------------------------------------------------------------------------------ 21 HD42581 WFPC2 IMAGE PC1 F1042M CR- 1 300S POS TARG 0.2275, 0.2275 SPLIT=NO,READ=Y ES,ATD- GAIN=7,CLOCKS=Y ES ------------------------------------------------------------------------------------------------------------------------------------ 6338( 16) - 03/04/96 15:45 - [ 9] Scan Paramters Form ------------------------------------------------------------------------------------------------------------------------------------ Data ID: 1 Exposure Logsheet lines: 4.010,6.010 FGS Scan: D Dwell Only: dwell points/line: 2 Seconds per dwell: 1.60 Scan width (arc-secs): 0.2275 Scan length (arc-secs): 0.2275 Angle between sides (degrees) 90.00 Number of lines: 2 Scan rate (arc-sec/sec): 0.0000 PA of first scan line (degrees) 90.000 Scan frame (CEL or S/C): S/C Length Offset (arc-sec): 0.2275 Width Offset (arc-sec): 0.2275 ------------------------------------------------------------------------------------------------------------------------------------ 6338( 16) - 03/04/96 15:45 - [ 10] Summary Form for Proposal 6338 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO SCAN-READ=ALL READ=YES ATD-GAIN=15 CLOCKS=YES ATD-GAIN=7 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Cool Stars ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 328D TO 333D SPATIAL SCAN 1 POS TARG 0.2275, 0.2275 ORIENT 148D TO 148D AFTER 01 BY 175D TO 198D ORIENT 328D TO 328D BETWEEN 9-NOV-1996 AND 23-NOV-1996 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F1042M F814W F675W ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD42581 ------------------------------------------------------------------------------------------------------------------------------------