DDT TOO REQUEST OF THE INTERLOPER
C/2025 N1 represents the first credible opportunity to detect soft X-ray emission from solar wind charge exchange (SWCX) in an interstellar comet. Interstellar comets are important because they provide direct samples of volatile substances from other planetary systems, preserving the chemical composition of exsolar protoplanetary discs and enabling comparisons between extrasolar planet-formation environments and our own. When active near perihelion, their neutral comae can attain scales of 10^5--10^6 km. SWCX emissions from this extensive "halo" identify the content and spatial distribution of neutral gas and volatile material, a capability beyond that of optical and infrared studies.
TELESCOP= 'XRISM ' / Mission name INSTRUME= 'RESOLVE ' / Instrument name FILTER = 'FE55 ' / Filter name used OBS_ID = '902001110' / Observation identification string OBJECT = 'C2025_N1' / Object name OBSERVER= 'XRISM Collaboration' / PI name OBS_MODE= 'POINTING' / POINTING or SLEW or ALL RA_OBJ = 182.7389 / [deg] Object Right ascension DEC_OBJ = -0.3519 / [deg] Object Declination RA_PNT = 182.735011716647 / Pointing RA DEC_PNT = -0.350483120236309 / Pointing DEC RA_NOM = 182.738995922148 / [deg] Nominal aspect point R.A. DEC_NOM = -0.351395985922451 / [deg] Nominal aspect point Dec. PA_NOM = 109.482537233029 / [deg] Nominal aspect point roll. TELAPSE = 9164 / Elapsed time DATE-OBS= '2025-11-28T08:01:16' / Start date DATE-END= '2025-11-28T10:34:00' / Stop date ONTIME = 843.0323118 / On-source time EXPOSURE= 843.0323118 / Exposure time PROCVER = '03.03.015.012' / Processing script version MKFFF = 'ISAS/JAXA' / Origin of First FITS file ORIGIN = 'GSFC/NASA' / Origin of Processed FITS file SOFTVER = 'Hea_26Sep2025_V6.36_XRISM_12Sep2025_V003' / Version of HEADAS used CALDBVER= 'gen20241115_xtd20250915_rsl20250915' / Version of CALDB used DATE = '2025-12-03T04:58:44' / Date and time this file was created or updated SIB2_VER= 'V04.00 ' / SIB2 version JAXA