# # Program information file # PROGRAM_ID 2022A066 PROGRAM_TITLE Catching the Wind: Uncovering the peculiar mass loss histories of Symbiotic X-ray binaries with iSHELL spectroscopy PROGRAM_INV1 Kishalay De PROGRAM_INV2 Roberto Soria PROGRAM_INV3 Ryan Lau PROGRAM_INV4 Viraj Karambelkar PROGRAM_INV5 Mansi Kasliwal PROGRAM_SCICAT stellar PROGRAM_ABSTRACT_BEG Symbiotic X-ray binaries [SyXRBs] are a rare, poorly understood class of sources consisting of a neutron star [NS] or black hole [BH] accreting from the wind of a very late type giant star. Early X-ray and low resolution near-infrared [NIR] spectroscopic observations tentatively suggested that SyXRB donors exhibit extreme mass loss properties that power their highly transient X-ray emission, and have been recently suggested from their first radio detections. However, the origin of the very high wind velocity [~ 250 km/s] in the NIR He I 1.08 micron line used to infer the elevated mass loss has not been confirmed, and plausibly could arise from an accretion disk outflow. The emergence of wide-field NIR synoptic time domain surveys offers a novel opportunity to study the long term pulsations of the highly obscured SyXRB donors and pin down their mass loss properties. As a pilot program to understand the nature of SyXRB variability, low resolution NIR spectroscopy has recently revealed similar high velocity winds in a sample of SyXRBs for the first time, suggesting that they may be ubiquitous. Here, we propose to use IRTF + iSHELL to carry out multi-epoch, high resolution NIR spectroscopy of these sources to use i] the temporal variability of the proposed wind signature, ii] the global radial velocity changes of the donor's atmosphere and iii] the photometric variability of the sources to conclusively probe the nature of the donor winds. The excellent infrared site of IRTF as well as the unique high resolution capabilities of iSHELL are ideally suited to study these bright infrared sources. Combined with NASA Swift X-ray follow-up, these observations will probe long unanswered questions about the active lifetimes of SyXRBs, the quiescent population demographics, their rare formation pathways and the poorly constrained mass loss rates of evolved stars. PROGRAM_ABSTRACT_END