XRISM XTEND observation 201108010

Title

DYNAMICS OF THE EXPLOSIVE DUST FORMATION NEAR PERIASTRON IN WR140

Abstract

Cosmic dust is a primary building block of the Earth, and its formation is a fundamental question. The massive colliding wind binary system, WR140, produces massive dust near periastron of its 7.9-year-long orbit. During the dust emission rise in previous binary cycles, the CIII line excess enhanced, and the X-ray emission declined oppositely, suggesting strong cooling of the WWC plasma produced a condition for dust formation. The star experiences another periastron passage on November 22nd, 2024. We propose 3 XRISM observations around that time to study the location and motion of the WWC plasma using the Fe XXV emission line. We also expect to detect the fluorescent Fe line, which strongly constrains the distance of the WWC apex from the stellar surface.

FITS header

TELESCOP= 'XRISM   '           / Mission name
INSTRUME= 'XTEND   '           / Instrument name
OBS_ID  = '201108010'          / Observation identification string
OBJECT  = 'WR140   '           / Object name
OBSERVER= 'KENJI HAMAGUCHI'    / PI name
OBS_MODE= 'POINTING'           / POINTING or SLEW or ALL
RA_OBJ  =             305.1166 / [deg] Object Right ascension
DEC_OBJ =              43.8545 / [deg] Object Declination
RA_PNT  =      305.13502159775 / Pointing RA
DEC_PNT =      43.857227304831 / Pointing DEC
RA_NOM  =     305.115071269235 / [deg] Nominal aspect point R.A.
DEC_NOM =     43.8546105964562 / [deg] Nominal aspect point Dec.
PA_NOM  =     283.347555235044 / [deg] Nominal aspect point roll.
TELAPSE =     124655.963135988 / Elapsed time
DATE-OBS= '2024-10-04T12:16:37.036864' / Start date
DATE-END= '2024-10-05T22:54:13' / Stop date
ONTIME  =         63738.189815 / On-source time
EXPOSURE=         63738.189815 / Exposure time
PROCVER = '03.00.013.009'      / Processing script version
MKFFF   = 'ISAS/JAXA'          / Origin of First FITS file
ORIGIN  = 'GSFC/NASA'          / Origin of Processed FITS file
SOFTVER = 'Hea_21Aug2024_V6.34_XRISM_21Aug2024_V001' / Version of HEADAS used
CALDBVER= 'gen20240315_xtd20240815_rsl20240815' / Version of CALDB used
DATE    = '2024-10-17T19:55:18' / Date and time this file was created or updated
SIB2_VER= 'V03.01  '           / SIB2 version JAXA

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