A Search for Hydroxylamine (NH_2OH) toward Select Astronomical Sources

Observations of 14 rotational transitions of hydroxylamine (NH_2OH) using the NRAO 12 m telescope on Kitt Peak are reported toward IRC+10216, Orion KL, Orion S, Sgr B2(N), Sgr B2(OH), W3IRS5, and W51M. Although recent models suggest the presence of NH_2OH in high abundance, these observations resulted in non-detection. Upper limits are calculated to be as much as six orders of magnitude lower than those predicted by models. Possible explanations for the lower-than-expected abundance are explored

THz time-domain spectroscopy of mixed CO2–CH3OH interstellar ice analogs

The icy mantles of interstellar dust grains are the birthplaces of the primordial prebiotic molecular inventory that may eventually seed nascent solar systems and the planets and planetesimals that form therein. Here, we present a study of two of the most abundant species in these ices after water: carbon dioxide (CO2) and methanol (CH3OH), using TeraHertz (THz) time-domain spectroscopy and mid-infrared spectroscopy. We study pure and mixed-ices of these species, and demonstrate the power of the THz region of the spectrum to elucidate the long-range structure (i.e. crystalline versus amorphous) of the ice, the degree of segregation of these species within the ice, and the thermal history of the species within the ice. Finally, we comment on the utility of the THz transitions arising from these ices for use in astronomical observations of interstellar ices

Orion Source I's disk is salty

We report the detection of NaCl, KCl, and their $^{37}$Cl and $^{41}$K isotopologues toward the disk around Orion SrcI. About 60 transitions of these molecules were identified. This is the first detection of these molecules in the interstellar medium not associated with the ejecta of evolved stars. It is also the first ever detection of the vibrationally excited states of these lines in the ISM above v = 1, with firm detections up to v = 6. The salt emission traces the region just above the continuum disk, possibly forming the base of the outflow. The emission from the vibrationally excited transitions is inconsistent with a single temperature, implying the lines are not in LTE. We examine several possible explanations of the observed high excitation lines, concluding that the vibrational states are most likely to be radiatively excited via rovibrational transitions in the 25-35 {\mu}m (NaCl) and 35-45 {\mu}m (KCl) range. We suggest that the molecules are produced by destruction of dust particles. Because these molecules are so rare, they are potentially unique tools for identifying high-mass protostellar disks and measuring the radiation environment around accreting young stars.Comment: Accepted to ApJ. Analysis code at https://github.com/keflavich/Orion_ALMA_2016.1.00165.S, paper source at https://github.com/keflavich/SaltyDisk, and data at https://zenodo.org/record/121335

Mirror asymmetry in life and in space

All life on Earth is based on amino acids that don’t align with their mirror images. Telescopes looking near the center of our galaxy may reveal the source of that asymmetry

MOLECULAR DISCOVERY ACROSS THE ALMA BANDS: FROM SALTY DISKS TO COMPLEX MOLECULES AT 900 GHz

The Atacama Large Millimeter/sub-millimeter Array (ALMA) provides a view of our molecular universe with unprecedented sensitivity and resolution over more than 850 GHz in bandwidth from 84 -- 950 GHz. In this talk, I will cover three recent results that showcase not only ALMA's power to probe interstellar chemical evolution, but also the critical role of laboratory molecular spectroscopy efforts in interpreting ALMA observations. At lower frequencies, I will discuss our recent detections of the extraordinarily vibrationally excited inorganic salts NaCl and KCl in the disk of Orion Src I, which may prove to be a unique, and much needed, probe of embedded disks around high-mass protostars. Moving up both in frequency and complexity, I will highlight our detection of methoxymethanol (\chem{CH_3OCH_2OH}) in the high-mass star-forming region NGC 6334I in very high abundance that was directly enabled by complementary laboratory spectroscopy work. Finally, I will discuss the first broadband line survey conducted with ALMA at Bands 9 and 10, again toward NGC 6334I. I will comment on not only the power and quality of high-frequency observations with ALMA but also the need for renewed laboratory efforts at these frequencies, as highlighted by glycolaldehyde (\chem{HC(O)CH_2OH}) and ethylene glycol (\chem{(CH_2OH)_2})

GOTHAM AND ARKHAM: FIRST RESULTS FROM PROGRAMS TO EXPLORE AROMATIC CHEMISTRY AT THE EARLIEST STAGES OF STAR FORMATION

We will present an overview of the GOTHAM (GBT Observations of TMC-1: Hunting Aromatic Molecules) and ARKHAM (A Rigorous K-band Hunt for Aromatic Molecules) projects on the 100 m Robert C. Byrd Green Bank Telescope, and a number of first results. These observations, prompted by our earlier detection of benzonitrile (c-\chem{C_6H_5CN}) in TMC-1, are designed to probe the extent of hidden chemical complexity at the earliest stages of the star formation process. We will discuss the detections of new molecules in TMC-1, comment on the prospects for probing additional aromatic chemistry in this source, and examine the apparently widespread nature of benzonitrile through the early protostellar phase of star formation