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OBSID:
23382
 Title:
The power of space: Simultaneous X-ray and UV monitoring if an accretion low-mass star
Investigator:
G�nther
 Observer:
Günther, Hans
 Phone:
617-253-8008
 Email:
hgunther@mit.edu
Target Name:
TW Hya
 Sequence Number:
201369
 Instrument:
HRC-S
 Grating:
LETG
 SI Mode:
HSE_0002B
 Raster Scan:
N
 Annotated DOT:
MAR0821a

Proposal Number:
22200086
 Right Ascension:
165.466
 Declination:
-34.7047
 Status:
archived
 Start Date:
2021-03-08 23:24:02
Category:
STARS AND WD
 Type:
GO
 AO Cycle:
22
 Dither Flag:
Y
 Y Offset:

 Z Offset:
Est. Count Rate:
0.04
 Order-1 Count Rate:
0.06
 Exposure Time:
30.00
 Time Remaining:

 Reqd Start Time:

 Reqd Stop Time:
Period:

 Epoch:

 Start of Period:

 End of Period:

 PS Margin:

 PE Margin:

 Max Segments:
0

Trigger Level:
DEF
 Range Switch Lvl:
DEF
 Spect Mode:
DEF
 Antico Enab:
DEF
 Width Enab:
DEF
 Width Thold:
DEF
 Uld Enab:
DEF
 Upper Lvl Disc:
DEF
Blank Enab:
DEF
 U Blank Hi:
DEF
 V Blank Hi:
DEF
 U Blank Lo:
DEF
 V Blank Lo:
DEF
 Py Shutter Pos:
DEF
 My Shutter Pos:
DEF
 Timing Mode:
N

Abstract:
Accretion onto low-mass stars can be probed with specific X-ray signatures observable with Chandra. Observations of the classical T Tauri star (CTTS) TW Hya show variability in these X-ray signatures which imply changes of almost an order of magnitude in the accretion rate and surface filling factors. We aim to reveal new accretion physics by observing TW Hya with Chandra/LETGS simultaneously with already approved HST UV observations in the ULYSSES program. The UV and X-ray regimes include tracers of the accretion process, but it is still unclear how they are related, in particular since few simultaneous X-ray/UV observations exist.

Remarks:
The HST ULLYSES program is DD time. HST has promised to make good effort to co-ordinate with other space and ground observatories that have programs for simultaneous or contemporaneous observations. The visibility windows of Chandra and HST are almost identical. These observations can be split if required thermally as long as individual observations are coordinated with an HST observation.

psci Run:
288
 Processing Date:
Mar 15 2021
 psci Directory:
/nfs/maaxnew/r3/eZ/acis114e/acis114.log
OBSID:
23382
 SIM Mode:
HRC-S
 OTG Mode:
LETG
 Seq Number:
MAR0821a
 Target Name:
Histogram_I
 AO:
0
Start VCDU:
101429:064
 Start Time (UTC):
067:85617.159
 Stop Time (UTC):
068:26840.613
 Kilosecs:
27.6
 % Frames:
0.3
 # CCDs:
I5
# Frames:
8523
 # Events:
0
 Events/sec:
0
 PSCI errors:
0
 % drops:
0.1
 Bias Errs:
1
 FP Temp:
-116.4
Parameter Block:
0x0023c024
 Window Block:
0x00039014
 # Windows:
10
 FEP Mode:
Te3x3
 BEP Mode:
EH
 Start Row:
0
 # Rows:
1024
Primary Exposure:
32
 Secondary Exposure:
0
 Duty Cycle:
0
 Summing?:
No
 Bias?:
Yes
 Trickle?:
No
 Bias Run:
288

pgf@space.mit.edu Sat Mar 29 10:37:19 EST 2025