# # Program information file # PROGRAM_ID 2023A016 PROGRAM_TITLE Water-ice mantles around coalesced stars PROGRAM_INV1 Tomasz Kaminski PROGRAM_INV2 Thomas Steinmetz PROGRAM_INV3 Muhammad Zain Mobeen PROGRAM_INV4 PROGRAM_INV5 PROGRAM_SCICAT stellar PROGRAM_ABSTRACT_BEG Red novae are stellar eruptions caused by stellar mergers. After their spectacular outbursts, these objects cool down to low temperatures and develop complex circumstellar environments [e.g. disks, outflows, jets] that are rich in dust. Most of the dust condenses after the eruptions, but there are hints that some dust-rich material may predate the eruptions and thus may evidence mass loss long before the merger. In one red nova remnant, V4332 Sgr, a water-ice feature at 3 um was reported a decade after the outburst, indicating either that ice mantles form rapidly after the eruption or that ice-rich material can survive a red nova outburst. The latter would evidence a copious mass loss in the progenitor system and may be involved in mechanisms driving binaries to merge. We propose to observe the 3 um water band in three red nova remnants [V1309 Sco, BLG360, and V4332 Sgr] to investigate whether it is a common feature among low-mass merger products and how the mantles change over the post-outburst evolution of the coalesced stars. The objects proposed here for observations are currently 14, 20, and 28 years after their red nova outbursts. We propose to acquire the spectra with the SpeX spectrograph at a resolution of R~1000 which will allow studying the band structure and the potential presence of ammonia-hydrates absorption near the water band. The proposed observations are important for understanding mass-loss phenomena in systems before and after a merger, and strongly constrain theoretical studies of the common envelope and related systems. PROGRAM_ABSTRACT_END