WR140
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.
obsid = 201109010 / Unique Observation/Sequence Number
object = WR140 / Object name
pi_name = HAMAGUCHI KENJI / Proposal Principal Investigator Name
ra = 305.117846595169 / Right Ascension (Pointing Position) (deg)
dec = 43.8541325978063 / Declination (Pointing Position) (deg)
roll_angle = 189.858519739552 / Roll Angle (deg)
start_time = 2025-01-12T15:06:04 / Start Time of the Observation
stop_time = 2025-01-14T10:56:04 / Stop Time of the Observation
exposure = 80791.984663 / Effective Total Observation Exposure (s)
public_date= 2026-01-22 / Public Date