PI_AQR
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.
obsid = 201103010 / Unique Observation/Sequence Number
object = PI_AQR / Object name
pi_name = GUNDERSON SEAN / Proposal Principal Investigator Name
ra = 336.319878868831 / Right Ascension (Pointing Position) (deg)
dec = 1.37734505414011 / Declination (Pointing Position) (deg)
roll_angle = 250.496860299224 / Roll Angle (deg)
start_time = 2024-11-17T12:44:04 / Start Time of the Observation
stop_time = 2024-11-19T00:25:04 / Stop Time of the Observation
exposure = 57604 / Effective Total Observation Exposure (s)
public_date= 2025-12-11 / Public Date