Unveiling the enigma of the Nakashima-Deguchi object (IRAS 19312+1950): A candidate Orion KL analog

The Nakashima-Deguchi object (NDO; also known as IRAS 19312+1950) has been recognized as enigmatic, exhibiting characteristics of both an evolved star and a star-forming region. However, the actual nature of this object remains a topic of ongoing debate. We aim to provide constraints on the nature of NDO by elucidating its molecular composition and dust content. We conducted observations of this object in (sub)millimeter continuum and molecular line emission using the IRAM-30m and APEX telescopes as well as the Submillimeter Array (SMA). Based on spectral energy distribution fitting of single-dish continuum observations, we determine that the cloud hosting NDO has a dust temperature of 25 $, a dust emissivity index of 1.7 K, a source-averaged (24 $ cm H_2 column density of $(4.4± 0.6) 10^ 22 -2 and a total gas mass of 220 M_⊙. SMA continuum observations resolve the cloud into at least four dust continuum cores. The centrally peaked millimeter core 1 (MM1), associated with an SiO maser, is the primary mass reservoir. Single-dish spectroscopic observations of NDO led to the detection of 59 spectral lines attributed to 12 species and their isotopologs. This includes the first detection of the deuterated molecules DCO^+, DCN, DNC, and HDCO toward NDO, indicating substantial deuterium abundance. SMA spectroscopic observations detect 75 spectral lines toward MM1, assigned to 12 species and their isotopologs. These lines exhibit diverse morphologies on a scale of $∼0.1 pc, likely due to outflow feedback. The observed high-velocity outflow is inconsistent with a spherical morphology and rather resembles a wide-angle bipolar outflow. Based on the detected molecular inventory, the presence of deuterated species, and the overall high mass of the complex, the surrounding material of NDO appears more naturally associated with a star-forming environment than with a purely evolved-star scenario. Our investigations lead us to postulate that this enigmatic object may represent an Orion KL analog located approximately ten times farther away.