TY - JOUR
T1 - The salty emission of the intermediate-mass AGB star OH 30.1−0.7
AU - Danilovich, T
AU - Richards, A M S
AU - Van de Sande, M
AU - Gottlieb, C A
AU - Millar, T J
AU - Karakas, A I
AU - Müller, H S P
AU - Justtanont, K
AU - Plane, J M C
AU - Etoka, S
AU - Wallström, S H J
AU - Decin, L
AU - Engels, D
AU - Groenewegen, M A T
AU - Kerschbaum, F
AU - Khouri, T
AU - de Koter, A
AU - Olofsson, H
AU - Paladini, C
AU - Stancliffe, R J
PY - 2025/1/1
Y1 - 2025/1/1
N2 - We analyse continuum and molecular emission, observed with ALMA, from the dust-enshrouded intermediate-mass AGB star OH 30.1 −0.7. We find a secondary peak in the continuum maps, “feature B”, separated by 4.6″ from the AGB star, which corresponds to a projected separation of 1.8 × 104 au, placing a lower limit on the physical separation. This feature is most likely composed of cold dust and is likely to be ejecta associated with the AGB star, though we cannot rule out that it is a background object. The molecular emission we detect includes lines of CO, SiS, CS, SO2, NS, NaCl, and KCl. We find that the NS emission is off centre and arranged along an axis perpendicular to the direction of feature B, indicative of a UV-emitting binary companion (e.g. a G-type main sequence star or hotter), perhaps on an eccentric orbit, contributing to its formation. However, the NaCl and KCl emission constrain the nature of that companion to not be hotter than a late B-type main sequence star. We find relatively warm emission arising from the inner wind and detect several vibrationally excited lines of SiS (v=1), NaCl (up to v=4) and KCl (up to v=2), and emission from low energy levels in the mid to outer envelope, as traced by SO2. The CO emission is abruptly truncated around 3.5″ or 14,000 au from the continuum peak, suggesting that mass loss at a high rate may have commenced as little as 2800 years ago.
AB - We analyse continuum and molecular emission, observed with ALMA, from the dust-enshrouded intermediate-mass AGB star OH 30.1 −0.7. We find a secondary peak in the continuum maps, “feature B”, separated by 4.6″ from the AGB star, which corresponds to a projected separation of 1.8 × 104 au, placing a lower limit on the physical separation. This feature is most likely composed of cold dust and is likely to be ejecta associated with the AGB star, though we cannot rule out that it is a background object. The molecular emission we detect includes lines of CO, SiS, CS, SO2, NS, NaCl, and KCl. We find that the NS emission is off centre and arranged along an axis perpendicular to the direction of feature B, indicative of a UV-emitting binary companion (e.g. a G-type main sequence star or hotter), perhaps on an eccentric orbit, contributing to its formation. However, the NaCl and KCl emission constrain the nature of that companion to not be hotter than a late B-type main sequence star. We find relatively warm emission arising from the inner wind and detect several vibrationally excited lines of SiS (v=1), NaCl (up to v=4) and KCl (up to v=2), and emission from low energy levels in the mid to outer envelope, as traced by SO2. The CO emission is abruptly truncated around 3.5″ or 14,000 au from the continuum peak, suggesting that mass loss at a high rate may have commenced as little as 2800 years ago.
KW - salty emission
KW - ntermediate-mass AGB star
KW - continuum and molecular emission
KW - cold dust
U2 - 10.1093/mnras/stae2584
DO - 10.1093/mnras/stae2584
M3 - Article
SN - 0035-8711
VL - 536
SP - 684
EP - 713
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 1
ER -