6258( 3) - 08/04/95 11:49 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6258 Version: 3 Check-in Date: ********** 1.Proposal Title: Is the Chiron Occultation Star, Ch02, a Double? ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Cool Stars GTO/HSP 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Robert C. Bless University of Wisconsin CoI: Amanda S. Bosh Lowell Observatory Y CoI: James L. Elliot Massachusetts Institute of Technology N CoI: Otto G. Franz Lowell Observatory N ------------------------------------------------------------------------------------ 6. Abstract We observed an occultation of the star Ch02 by Chiron on 1993 November 7 from five locations, but the light curves obtained have defied explanation so far (see IAUC 5898). What we were expecting to see was an occultation by Chiron's nucleus--a sharp drop of the stellar flux to zero that would last a few seconds before abruptly returning to full scale. However, the observed occultation was only 75% of the total starlight. So, either the star is a close double, or Chiron's nucleus has a bizarre structure. The double-star hypothesis will be tested with FGS observations. ------------------------------------------------------------------------------------ Observations Description ------------------------ The star Ch02 will be examined for duplicity with the FGS at two epochs. The proposed observations should reach a sensitivity of 0.02 arcsec or duplicity if delta mag is 1.6 which it has to be to explain the incomplete occultation (observed). Two epochs of observations are needed to be sure that the separation of the components is not oriented perpendicular to the measurement of the FGS for a particular epoch. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 6258( 3) - 08/04/95 11:49 - [ 2] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: Amanda S. Bosh*Lowell Observatory*1400 W. Mars Hill Road*Flagstaff, AZ 86001- 4499 Ship Via: UPS Email: amanda@lowell.edu , ------------------------------------------------------------------------------------ 6258( 3) - 08/04/95 11:49 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 CH02 STAR RA=10H 28M 08.057S +/- 0.5", J2000 V = 14.3 +/- 0.1 DEC=3D 30' 35.748" +/- 0.5", B-V= 1.0 +/- 0.1 PLATE-ID=01FY V-R= 0.6 +/- 0.1 V-I= 1.2 +/- 0.1 Comments: Finder chart available in Bus et al., AJ 107, 1814. 6258( 3) - 08/04/95 11:49 - [ 4] Visit: 01 Visit Requirements: PCS MODE Fine orient 304d to 306d 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 CH02 FGS TRANS 3 F583W 5830 DATA-RATE = 32, 1 1440S POS TARG 0.0, 0.0 STEP-SIZE = 1.0, SCANS = 48, ACQ-MODE = SEARCH Comments: This seq will make 48 scans across the star at a scan length of 1.2 arcsec on each interferometric axis in steps of 1 mas. It will repeat the obs at an orient that is + or - 45D (+/-15D). ------------------------------------------------------------------------------------------------------------------------------------ 6258( 3) - 08/04/95 11:49 - [ 5] Visit: 02 Visit Requirements: PCS MODE Fine ORIENT 335D TO 345D On Hold Comments: Additional Comments: Optimal orientation is either +45D or -45D from Visit 1. ORIENT can also be -30D to -60D FROM 1 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 2 CH02 FGS TRANS 3 F583W 5830 DATA-RATE = 32, 1 1440S POS TARG 0.0, 0.0 STEP-SIZE = 1.0, SCANS = 48, ACQ-MODE = SEARCH ------------------------------------------------------------------------------------------------------------------------------------ 6258( 3) - 08/04/95 11:49 - [ 6] Summary Form for Proposal 6258 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FGS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes TRANS ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters DATA-RATE = 32 STEP-SIZE = 1.0 SCANS = 48 ACQ-MODE = SEARCH ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GTO/HSP ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Cool Stars ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PCS MODE Fine orient 304d to 306d POS TARG 0.0, 0.0 PCS MODE Fine ORIENT 335D TO 345D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F583W ------------------------------------------------------------------------------------------------------------------------------------ Target Names CH02 ------------------------------------------------------------------------------------------------------------------------------------