Proposal_Information Title: Boron abundances in Orion and boron production in Type II Supernovae Proposal_Category: GO Scientific_Category: Hot Stars Cycle: 5 Investigators PI_name: Dr. David L. Lambert PI_Institution: University of Texas at Austin CoI_Name: Dr. Katia Cunha CoI_Institution: University of Texas at Austin Contact: N CoI_Name: Dr. D.R. Gies CoI_Institution: Georgia State University Contact: N CoI_Name: Dr. Lewis Roberts CoI_Institution: Georgia State University Contact: N CoI_Name: Dr. M. Lemke CoI_Institution: University of Cambridge Contact: N Abstract: The Orion OB1 association comprises four subgroups of differing ages. The youngest stars show higher oxygen abundances than the oldest stars. This enrichment has been shown to be due to contamination of the natal gas by oxygen- rich ejecta from supernovae. The boron abundance will be derived from the B II 1362 Angstrom line for three stars in the Orion OB1 association having different oxygen abundances. A positive correlation of the boron and oxygen abundance will, if present, indicate that boron, as ^11B, is synthesized by the supernovae held responsible for the oxygen abundances. This will be the first direct evidence for ^11B production by supernovae. Questions Observing_Description: The B II resonance line at 1362.46 A will be observed with GHRS in the same way as we observed our first target in Cycle 3: G160M grating centered at 1362.5 A and used with the Small Science Aperture (for best spectral resolution) and the A2 mirror for target acquisition. With this arrangement we cover some 35 A of spectra which includes several other Si III lines needed to estimate line blending near the B II line. We are aiming to achieve a high signal-to-noise (about 600-1000 per pixel) similar to what we obtained on the first target in Cycle 3. Exposure times (below) were calculated from the UV fluxes measured in TD1 and IUE spectra of the targets. Our proposed targets have low projected rotational velocities (V sin i), as well as effective temperatures low enough so that the B II transition can be accurately measured. A list of the stars, with their respective effective temperatures, gravities, O abundances, UV fluxes, and exposure times, is given below. Target Teff log g O Abundance Flux (1362 A) Exposure (min.) HD35039 20550 3.74 O-normal 1.2e-9 35 HD36285 21930 4.40 O 60% above 3.6e-10 40 HD36430 19640 4.36 O 50% above 3.5e-10 40 Real_Time_Justification: Calibration_Justification: Additional_Comments: We would prefer to have all targets observed during one suite of observations. Fixed_Targets Target_Number: 1 Target_Name: HD35039 Alternate_Names: 22-ORI,HR1765, GSC4752-01608 Description: STAR, B0-B2 V-IV Position: RA=05H 21M 45.74S +/- 0.01S, DEC=-00D 22' 57.0" +/- 0.1" Equinox: J2000 RV_or_Z: V = 29 RA_PM: -0.0003 Dec_PM: -0.001 Epoch: 2000 Annual_Parallax: 0.002 Flux: V = 4.69, B-V = -0.17 +/- 0.02, TYPE = B2IV-V, F-CONT(1362) = 1.2 +/- 0.2 E-9 Comments: O-NORMAL, Coordinates are from Hipparcos INCA Target_Number: 2 Target_Name: HD36285 Alternate_Names: HR1840, GSC4778-01409 Description: STAR, B0-B2 V-IV Position: RA=05H 30M 20.75S +/- 0.01S, DEC=-07D 26' 5.3" +/- 0.1" Equinox: J2000 RV_or_Z: V = 11 RA_PM: -0.0013 Dec_PM: 0.000 Epoch: 2000 Annual_Parallax: 0.002 Flux: V = 6.33 +/- 0.02, B-V = -0.19 +/- 0.02, TYPE = B2IV-V, F-CONT(1362) = 3.6 +/- 0.5 E-10 Comments: O+60%, Coordinates are from Hipparcos INCA Target_Number: 3 Target_Name: HD36430 Alternate_Names: HR1848, GSC4778-01405 Description: STAR, B0-B2 V-IV Position: RA=05H 31M 20.92S +/- 0.01S, DEC=-06D 42' 30.0" +/- 0.1" Equinox: J2000 RV_or_Z: V = 23 RA_PM: 0.0003 Dec_PM: 0.000 Epoch: 2000 Annual_Parallax: 0.002 Flux: V = 6.19, B-V = -0.17 +/- 0.02, TYPE = B2V, F-CONT(1362) = 3.5 +/- 0.5 E-10 Comments: O+50%, Coordinates are from Hipparcos INCA Visits Visit_Number: 1 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 1 Target_Name: HD35039 Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-A2 Wavelength: Optional_Parameters: BRIGHT=RETURN, SEARCH-SIZE=3 Number_of_Iterations: 1 Time_Per_Exposure: 1.8S Special_Requirements: ONBOARD ACQ FOR 2 Comments: IN ACQ EXPECT ABOUT 66000 CTS/S, STEP-TIME=0.2S Exposure_Number: 2 Target_Name: HD35039 Config: HRS Opmode: ACQ/PEAKUP Aperture: 0.25 Sp_Element: MIRROR-A2 Wavelength: Optional_Parameters: SEARCH-SIZE=5 Number_of_Iterations: 1 Time_Per_Exposure: 5.0S Special_Requirements: ONBOARD ACQ FOR 3 Comments: IN ACQ EXPECT ABOUT 44000 CTS/S, STEP-TIME=0.2S Exposure_Number: 3 Target_Name: HD35039 Config: HRS Opmode: ACCUM Aperture: 0.25 Sp_Element: G160M Wavelength: 1362.0 Optional_Parameters: FP-SPLIT=STD, COMB=FOUR, STEP-PATT=DEF, DOPPLER=DEF, STEP-TIME=0.2 Number_of_Iterations: 8 Time_Per_Exposure: 327S Special_Requirements: Comments: EXPECTED COUNT RATE = 480, EXPECTED S/N = 1080 Visit_Number: 2 Visit_Requirements: ! Section 7.1 On_Hold_Comments: Visit_Comments: Exposure_Number: 1 Target_Name: HD36285 Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-A2 Wavelength: Optional_Parameters: BRIGHT=RETURN, SEARCH-SIZE=3 Number_of_Iterations: 1 Time_Per_Exposure: 1.8S Special_Requirements: ONBOARD ACQ FOR 2 Comments: IN ACQ EXPECT ABOUT 22000 CTS/S, STEP-TIME=0.2S Exposure_Number: 2 Target_Name: HD36285 Config: HRS Opmode: ACQ/PEAKUP Aperture: 0.25 Sp_Element: MIRROR-A2 Wavelength: Optional_Parameters: SEARCH-SIZE=5 Number_of_Iterations: 1 Time_Per_Exposure: 5.0S Special_Requirements: ONBOARD ACQ FOR 3 Comments: IN ACQ EXPECT ABOUT 15000 CTS/S, STEP-TIME=0.2S Exposure_Number: 3 Target_Name: HD36285 Config: HRS Opmode: ACCUM Aperture: 0.25 Sp_Element: G160M Wavelength: 1362.0 Optional_Parameters: FP-SPLIT=STD, COMB=FOUR, STEP-PATT=DEF, DOPPLER=DEF, STEP-TIME=0.2 Number_of_Iterations: 8 Time_Per_Exposure: 327S Special_Requirements: Comments: EXPECTED COUNT RATE = 140, EXPECTED S/N = 600 Visit_Number: 3 Visit_Requirements: ! Section 7.1 On_Hold_Comments: Visit_Comments: Exposure_Number: 1 Target_Name: HD36430 Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-A2 Wavelength: Optional_Parameters: BRIGHT=RETURN, SEARCH-SIZE=3 Number_of_Iterations: 1 Time_Per_Exposure: 1.8S Special_Requirements: ONBOARD ACQ FOR 2 Comments: IN ACQ EXPECT ABOUT 20000 CTS/S, STEP-TIME=0.2S Exposure_Number: 2 Target_Name: HD36430 Config: HRS Opmode: ACQ/PEAKUP Aperture: 0.25 Sp_Element: MIRROR-A2 Wavelength: Optional_Parameters: SEARCH-SIZE=5 Number_of_Iterations: 1 Time_Per_Exposure: 5.0S Special_Requirements: ONBOARD ACQ FOR 3 Comments: IN ACQ EXPECT ABOUT 13000 CTS/S, STEP-TIME=0.2S Exposure_Number: 3 Target_Name: HD36430 Config: HRS Opmode: ACCUM Aperture: 0.25 Sp_Element: G160M Wavelength: 1362.0 Optional_Parameters: FP-SPLIT=STD, COMB=FOUR, STEP-PATT=DEF, DOPPLER=DEF, STEP-TIME=0.2 Number_of_Iterations: 8 Time_Per_Exposure: 327S Special_Requirements: Comments: EXPECTED COUNT RATE = 140, EXPECTED S/N = 600 Data_Distribution Medium: 8MM Blocking_Factor: 10 Ship_To: PI_Address Ship_Via: UPS Recipient_Email: