C H A N D R A   S C I E N C E   C E N T E R
O B S E R V A T I O N   C A T A L O G

OBSID:
27269
 Title:
Identifying the nature of the gamma Cas like system, pi Aqr, with HETGS  
Investigator:
Canizares
 Observer:
Pradhan, Pragati
 Phone:
814-699-0432
 Email:
pragati2707@gmail.com
Target Name:
pi aqr
 Sequence Number:
201489
 Instrument:
ACIS-S
 Grating:
HETG
 SI Mode:
TE_00958B
 Raster Scan:
N
 Annotated DOT:
AUG2322a

Proposal Number:
23200622
 Right Ascension:
336.319
 Declination:
1.3774
 Status:
archived
 Start Date:
2022-08-27 04:23:23
Category:
STARS AND WD
 Type:
GTO
 AO Cycle:
23
 Dither Flag:
Y
 Y Offset:
0
 Z Offset:
0
Est. Count Rate:
0.13
 Order-1 Count Rate:
0.11
 Exposure Time:
10
 Time Remaining:
10.124
 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:
2
 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:
gamma Cas type stars are enigmatic and exhibit peculiar X-ray characteristics that make them very different from other main sequence B stars. Recent arguments based on binary evolution models have indicated the possibility that the gamma Cas analogues could be binaries made of a Be star and a Helium star. pi Aqr is the third brightest of gamma Cas analogues. This observation of pi Aqr with HETGS will help characterize its plasma properties, particularly emission line strenghs and shapes characteristic of high temperatures, and will to aid in determining the origin of the emission in the context of stellar winds and wind-wind or wind-disk collisions.

psci Run:
132
 Processing Date:
Sep 7 2022
 psci Directory:
/nfs/maaxnew/r3/fg/acis121c/acis121.log
OBSID:
27269
 SIM Mode:
ACIS-S
 OTG Mode:
HETG
 Seq Number:
201489
 Target Name:
pi_aqr
 AO:
23
Start VCDU:
19511:016
 Start Time (UTC):
239:16885.383
 Stop Time (UTC):
239:27021.466
 Kilosecs:
10.1
 % Frames:
100.0
 # CCDs:
S4
# Frames:
3227
 # Events:
320071
 Events/sec:
31
 PSCI errors:
0
 % drops:
0.0
 Bias Errs:
0
 FP Temp:
-119.2
Parameter Block:
0x00958024
 Window Block:
-
 # Windows:
0
 FEP Mode:
Te3x3
 BEP Mode:
F
 Start Row:
0
 # Rows:
1024
Primary Exposure:
31
 Secondary Exposure:
0
 Duty Cycle:
0
 Summing?:
No
 Bias?:
Yes
 Trickle?:
Yes
 Bias Run:
132

pgf@space.mit.edu Mon Mar 31 10:36:39 EST 2025