000007662 001__ 7662
000007662 005__ 20251226131057.0
000007662 037__ $$aSCART-2025-0153
000007662 100__ $$aGoldman, S.R.
000007662 245__ $$aEquatorial Enhancement in the Dustiest OH/IR Stars in the Galactic Bulge
000007662 260__ $$c2025
000007662 520__ $$aWe have detected the 10 μm silicate feature and the 11.3 μm crystalline forsterite feature in absorption in 21 oxygen-rich asymptotic giant branch stars in the Galactic bulge. The depths of the 10 μm feature indicate We have detected the 10 μm silicate feature and the 11.3 μm crystalline forsterite feature in absorption in 21 oxygen-rich asymptotic giant branch stars in the Galactic bulge. The depths of the 10 μm feature indicate highly obscured circumstellar environments. The additional crystalline features may suggest either an extended envelope or dust formation in a high-density environment. We have also modeled the spectral energy distributions (SEDs) of the sample using radiative transfer models, and compared the results to wind speeds measured using 1612 MHz circumstellar OH masers, as well as previous estimates of circumstellar properties. The 16 sources with measured pulsation periods appear on sequence D of the mid-IR period–luminosity relation, associated with the long secondary period. We suspect that all of these sources are in fact fundamental-mode pulsators. At least two sources appear on the fundamental-mode sequence when accounting for the dust content. For the remainder, these sources are also likely fundamental-mode pulsators with extended envelopes. Taken as a whole, the high optical depths, crystalline features, discrepancies between observed and modeled wind speeds, pulsation periods longer than other fundamental-mode pulsators, and SED and pulsation properties similar to those with known equatorially enhanced circumstellar envelopes (e.g., OH 26.5+0.6 and OH 30.1–0.7) lead us to believe that these sources are likely to be equatorially enhanced, highly obscured circumstellar environments. The additional crystalline features may suggest either an extended envelope or dust formation in a high-density environment. We have also modeled the spectral energy distributions (SEDs) of the sample using radiative transfer models, and compared the results to wind speeds measured using 1612 MHz circumstellar OHmasers, as well as previous estimates of circumstellar properties. The 16 sources with measured pulsation periods appear on sequence D of the mid-IR period–luminosity relation, associated with the long secondary period. We suspect that all of these sources are in fact fundamental-mode pulsators. At least two sources appear on the fundamental-mode sequence when accounting for the dust content. For the remainder, these sources are also likely fundamental-mode pulsators with extended envelopes. Taken as a whole, the high optical depths, crystalline features, discrepancies between observed and modeled wind speeds, pulsation periods longer than other fundamental-mode pulsators, and SED and pulsation properties similar to those with known equatorially enhanced circumstellar envelopes (e.g., OH 26.5+0.6 and OH 30.1–0.7) lead us to believe that these sources are likely to be equatorially enhanced.
000007662 594__ $$aNO
000007662 6531_ $$aGalactic bulge
000007662 6531_ $$aStellar mass loss
000007662 6531_ $$aAsymptotic giant branch stars
000007662 6531_ $$aStellar winds
000007662 6531_ $$aCircumstellar dust
000007662 6531_ $$aLong period variable stars
000007662 700__ $$avan Loon, J.Th.
000007662 700__ $$aJones, O.C.
000007662 700__ $$aBlommaert, J.A.D.L
000007662 700__ $$aGroenewegen, M.A.T.
000007662 773__ $$c191$$pastrophysical journal$$v980$$y2025
000007662 8560_ $$fmartin.groenewegen@ksb-orb.be
000007662 8564_ $$s1301820$$uhttp://publi2-as.oma.be/record/7662/files/GoldmanvanLoon_ea_25ApJ_980_191_Dustiest_OHIR_GalacricBulge.pdf
000007662 8564_ $$s3677$$uhttp://publi2-as.oma.be/record/7662/files/GoldmanvanLoon_ea_25ApJ_980_191_Dustiest_OHIR_GalacricBulge.gif?subformat=icon$$xicon
000007662 8564_ $$s7021$$uhttp://publi2-as.oma.be/record/7662/files/GoldmanvanLoon_ea_25ApJ_980_191_Dustiest_OHIR_GalacricBulge.jpg?subformat=icon-180$$xicon-180
000007662 905__ $$apublished in
000007662 980__ $$aREFERD