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OBSID:
24760
 Title:
Diagnosing Winds and Magnetic Confinement in Massive Stars    
Investigator:
Canizares
 Observer:
Huenemoerder, David
 Phone:
617-253-4283
 Email:
dph@space.mit.edu
Target Name:
rho Oph A
 Sequence Number:
201417
 Instrument:
ACIS-S
 Grating:
HETG
 SI Mode:
TE_0088EB
 Raster Scan:
N
 Annotated DOT:
MAR2122a

Proposal Number:
22200692
 Right Ascension:
246.396
 Declination:
-23.4472
 Status:
archived
 Start Date:
2022-03-22 22:53:29
Category:
STARS AND WD
 Type:
GTO
 AO Cycle:
22
 Dither Flag:
Y
 Y Offset:
0
 Z Offset:
0
Est. Count Rate:
0.0146
 Order-1 Count Rate:
0.0268
 Exposure Time:
30
 Time Remaining:
28.944
 Reqd Start Time:

 Reqd Stop Time:
Period:

 Epoch:

 Start of Period:

 End of Period:

 PS Margin:

 PE Margin:

 Max Segments:
0

ACIS Mode:
TE
 Standard?:
No
 BEP Mode:
F
 Dropped Chip Count:
0
 Optional Chips:
S0 S5
On-Chip Summing?:
No
 Row Sum:

 Column Sum:

 Frame Time:
Subarray Mode:
NONE
 Starting Row:
0
 Row Count:
1023
 Subarray Frame Time:

Duty Cycle?:
No
 Cycle Count:
0
 Primary Exp Time:

 Secondary Exp Time:
Event Filter?:
No
 Filter Threshold:

 Filter Range:

 Bias Requested?:
No
 Bias Frequency:

 Bias After?:
No
 Spatial Window?:
No

Abstract:
Mass-loss rates of massive stars are poorly constrained, yet have far-reaching consequences. Late O- and B-type dwarfs have weaker winds than expected. Magnetic fields have been found in massive stars and can limit mass loss. X-rays from some weak-wind stars are not weak, hinting that optical/UV diagnostics are incomplete. rho Oph A is a B2 V star with a magnetic field. High-resolution X-ray spectra from HETGS will reveal any high-temperature-plasma wind and provide important clues regarding magnetically confined wind shocks and the weak-wind phenomenon. In a 200 ks exposure, we can accurately measure Mg XII and Si XIII line widths and centroids and thereby determine whether the hot plasma is characteristic of a magnetically confined wind, or is expanding as a weak or strong wind.

psci Run:
192
 Processing Date:
Apr 11 2022
 psci Directory:
/nfs/maaxnew/r3/fe/acis119c/acis119.log
OBSID:
24760
 SIM Mode:
ACIS-S
 OTG Mode:
HETG
 Seq Number:
201417
 Target Name:
rho_Oph_A
 AO:
22
Start VCDU:
51104:096
 Start Time (UTC):
081:83731.004
 Stop Time (UTC):
082:26289.792
 Kilosecs:
29.0
 % Frames:
100.0
 # CCDs:
S6
# Frames:
8935
 # Events:
1580317
 Events/sec:
54
 PSCI errors:
0
 % drops:
0.0
 Bias Errs:
0
 FP Temp:
-111.3
Parameter Block:
0x0088e024
 Window Block:
-
 # Windows:
0
 FEP Mode:
Te3x3
 BEP Mode:
F
 Start Row:
0
 # Rows:
1024
Primary Exposure:
32
 Secondary Exposure:
0
 Duty Cycle:
0
 Summing?:
No
 Bias?:
Yes
 Trickle?:
Yes
 Bias Run:
192

pgf@space.mit.edu Thu Apr 3 20:00:53 EST 2025