TESTING THE WHITE DWARF HYPOTHESIS FOR GAMMA CAS COMPANIONS
We propose to observe the two brightest gamma Cas-type stars: gamma Cas and pi Aqr for 30 and 50 ks, respectively. The X-ray generating mechanism in these stars is unknown, but recent work has attributed it to accretion onto unseen White Dwarf companions. If accretion is the source, then the X-ray spectra can be used to estimate masses and radii of the White Dwarfs from the plasma's maximum temperature, Fe K line shape quantities, and the mass-accretion rate from a cooling flow model; all of which should be self-consistent. Our plan is to use the high resolution and high energy sensitivity of XRISM to resolve both line emission and thermal continuum turn-over to constrain these quantities and calculate masses and radii as a method testing the self-consistency of the White Dwarf hypothesis.
TELESCOP= 'XRISM ' / Mission name INSTRUME= 'XTEND ' / Instrument name OBS_ID = '201103010' / Observation identification string OBJECT = 'PI_AQR ' / Object name OBSERVER= 'SEAN GUNDERSON' / PI name OBS_MODE= 'POINTING' / POINTING or SLEW or ALL RA_OBJ = 336.3193 / [deg] Object Right ascension DEC_OBJ = 1.3774 / [deg] Object Declination RA_PNT = 336.320770818296 / Pointing RA DEC_PNT = 1.37975529323651 / Pointing DEC RA_NOM = 336.319878868831 / [deg] Nominal aspect point R.A. DEC_NOM = 1.37734505414011 / [deg] Nominal aspect point Dec. PA_NOM = 250.496860299224 / [deg] Nominal aspect point roll. TELAPSE = 123614.963135988 / Elapsed time DATE-OBS= '2024-11-17T13:48:20.036864' / Start date DATE-END= '2024-11-19T00:08:35' / Stop date ONTIME = 51798.371677 / On-source time EXPOSURE= 51798.371677 / Exposure time PROCVER = '03.00.013.010' / 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= 'gen20241115_xtd20241115_rsl20241115' / Version of CALDB used DATE = '2024-12-01T23:34:58' / Date and time this file was created or updated SIB2_VER= 'V03.01 ' / SIB2 version JAXA