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: