GAMMA_VEL
We request two XRISM observations of the 78.5-day colliding-wind binary gamma Vel at key orbital phases (inferior and superior conjunction), when the shock-cone aspect changes most as one star passes directly in front of the other. These observations will test radiative braking effects on shock geometry and line shifts. Without braking, lines are red- and blue-shifted, while stationary plasma due to inhibition shows minimal centroid variation. We will focus on the FeXXV complex, which directly measures the hottest plasma formed in head-on wind collisions. Additional goals are to search for DR lines. Xtend will constrain absorption and the soft `relic' emission. As a short-period analog to the WR140, gamma Vel enables detailed shock studies on accessible timescales.
obsid = 203128010 / Unique Observation/Sequence Number
object = GAMMA_VEL / Object name
pi_name = PRADHAN PRAGATI / Proposal Principal Investigator Name
ra = 122.383536691213 / Right Ascension (Pointing Position) (deg)
dec = -47.3371242668711 / Declination (Pointing Position) (deg)
roll_angle = 355.897594951834 / Roll Angle (deg)
start_time = 2026-07-17T12:29:04 / Start Time of the Observation
stop_time = 2026-07-20T07:16:04 / Stop Time of the Observation
exposure = 112893.96091 / Effective Total Observation Exposure (s)
public_date= 2099-12-31 / Public Date