Search

High spectral resolution observations of Jupiter performed at the NASA/Infrared Telescope Facility near 13.5 μm are presented. Two spectral ranges including the R(7) and R(11) lines of the v2 band of HCN were observed at high signal-to-noise. No evidence for HCN absorption in excess of 2% of the continuum was found, in contrast to the report by Tokunaga et al . (1981, Icarus 48, 283-289). An upper limit on the tropospheric HCN mixing ratio of 1 × 10-9 was derived, assuming a uniform value up to the tropopause. When HCN condensation in the upper troposphere is taken into account, only a looser upper limit around 1.2 × 10-8 can be set on the deep mixing ratio. The lack of emission cores at the position of the HCN lines provides an upper limit of 2 × 10-4 cm-amagat on the HCN column density in the stratosphere (corresponding to a maximum average mixing ratio of 8 × 10-10 above condensation level). A critical reanalysis of Tokunaga et al.'s observations is finally presented, leading to the conclusion that the previously reported detection of HCN is questionable.

We present spectroscopy of the molecular shock in the supernova remnant IC 443. The H2 level populations in IC 443 are nearly identical to Orion Peak 1 (Brand et al. 1988; Parmar et al. 1994) and are consistent with a partially dissociative J-shock. The similarity with Orion suggests the shock processes which dominate the emission in both regions are essentially identical.

We have been using the TEXES high-resolution imaging spectrometer at the NASA Infrared Telescope Facility to map sulfur dioxide and deuterated water over the disk of Venus. Observations took place on January 10–12, 2012. The diameter of Venus was 13 arcsec, with an illumination factor of 80%. Data were recorded in the 1344–1370 cm −1 range (around 7.35 μm) with a spectral resolving power of 80 000 and a spatial resolution of about 1.5 arcsec. In this spectral range, the emission of Venus comes from above the cloud top (z = 60–80 km). Four HDO lines and tens of SO2 lines have been identified in our spectra. Mixing ratios have been estimated from HDO/CO2 and SO2/CO2 line depth ratios, using weak neighboring transitions of comparable depths. The HDO maps, recorded on Jan. 10 and Jan. 12, are globally uniform with no significant variation between the two dates. A slight enhancement of the HDO mixing ratio toward the limb might be interpreted as a possible increase of the D/H ratio with height above the cloud level. The mean H2O mixing ratio is found to be 1.5 +/−0.75 ppm, assuming a D/H ratio of 0.0312 (i.e. 200 times the terrestrial value) over the cloud deck. The SO2 maps, recorded each night from Jan. 10 to Jan. 12, show strong variations over the disk of Venus, by a factor as high as 5 to 10. In addition, the position of the maximum SO2 mixing ratio strongly varies on a timescale of 24 h. The maximum SO2 mixing ratio ranges between 75 +/−25 ppb and 125 +/−50 ppb between Jan. 10 and Jan. 12. The high variability of sulfur dioxide is probably a consequence of its very short photochemical lifetime.

International audience; Surfur-bearing molecules have been found at the surface of Mars by the Viking lander, the Spirit and Opportunity rovers, and the OMEGA infrared spectrometer aboard Mars Express. However, no gaseous sulfur-bearing species have ever been detected in the Martian atmosphere. We search for SO2 signatures in the thermal spectrum of Mars at 7.4 μm using the Texas Echelon Cross Echelle Spectrograph (TEXES) at the NASA Infrared Telescope Facility (IRTF). Data were obtained on Oct. 12, 2009 (Ls = 353°), in the 1350-1360 cm-1 range, with a spatial resolution of 1 arcsec (after convolution over three pixels along the N-S axis and two steps along the E-W axis) and a resolving power of 80 000. To improve the signal-to-noise ratio (S/N), we co-added the Martian spectrum around the positions of nine selected SO2 transitions with a high S/N and no telluric contamination. From a mean spectrum, averaged over 35 pixels in the region of maximum continuum, we infer a 2σ upper limit of 0.3 ppb to the SO2 mixing ratio, assuming that our instrumental errors are combined according to Gaussian statistics. Our upper limit is three times lower than the upper limit derived by Krasnopolsky (2005, Icarus, 178, 487), who used the same technique on previous TEXES data. In addition, we derive an upper limit of 2 ppb at each spatial pixel of the region observed by TEXES, which covers the longitude ranges 50 E-170 E for latitudes above 30 N, 100 E-170 E for latitudes between 0 and 30 N, and 110 E-170 E for latitudes between 15 S and 0. The non-detection of localized SO2 sources in the observed area is consistent with a homogeneous distribution being expected around equinox for non-condensible species with a lifetime longer than the global mixing time. In view of the typically large SO2/CH4 ratio observed in terrestrial volcanoes, and assuming a comparable volcanic composition for Mars and the Earth, our result reaffirms that a volcanic origin is unlikely for any methane in the Martian atmosphere.

A group of four compact HII regions associated with the well-known 50 km/s molecular cloud is the closest site of on-going star formation to the dynamical center of the Galaxy, at a projected distance of ~6 pc. We present a study of ionized gas based on the [NeII] (12.8 micron) line, as well as multi-frequency radio continuum, HST Pa alpha and Spitzer IRAC observations of the most compact member of the HII group, Sgr A East HII D. The radio continuum image at 6cm shows that this source breaks up into two equally bright ionized features, D1 and D2. The SED of the D source is consistent with it being due to a 25\pm3 solar mass, star with a luminosity of 8\pm3x10^4 solar luminosity. The inferred mass, effective temperature of the UV source and the ionization rate are compatible with a young O9-B0 star. The ionized features D1 and D2 are considered to be ionized by UV radiation collimated by an accretion disk. We consider that the central massive star photoevaporates its circumstellar disk on a timescale of 3x10^4 years giving a mass flux ~3x10^{-5} solar mass per yr and producing the ionized material in D1 and D2 expanding in an inhomogeneous medium. The ionized gas kinematics, as traced by the [Ne II] emission, is difficult to interpret, but it could be explained by the interaction of a bipolar jet with surrounding gas along with what appears to to be a conical wall of lower velocity gas. The other HII regions, Sgr A East A-C, have morphologies and kinematics that more closely resemble cometary flows seen in other compact HII regions, where gas moves along a paraboloidal surface formed by the interaction of a stellar wind with a molecular cloud., 29 pages, 9 figures, accepted by ApJ

The Korea Astronomy and Space Science Institute (KASI) and the Department of Astronomy at the University of Texas at Austin (UT) are developing a near infrared wide-band high resolution spectrograph, IGRINS. IGRINS can observe all of the H- and K-band atmospheric windows with a resolving power of 40,000 in a single exposure. The spectrograph uses a white pupil cross-dispersed layout and includes a dichroic to divide the light between separate H and K cameras, each provided with a 2kx2k HgCdTe detector. A silicon immersion grating serves as the primary disperser and a pair of volume phased holographic gratings serve as cross dispersers, allowing the high resolution echelle spectrograph to be very compact. IGRINS is designed to be compatible with telescopes ranging in diameter from 2.7m (the Harlan J. Smith telescope; HJST) to 4 - 8 m telescopes. Commissioning and initial operation will be on the 2.7m telescope at McDonald Observatory from 2013.

We are designing a sensitive high resolution (R=60,000-100,000) spectrograph for the Giant Magellan Telescope (GMTNIRS, the GMT Near-Infrared Spectrograph). Using large-format IR arrays and silicon immersion gratings, this instrument will cover all of the J (longer than 1.1 μm), H, and K atmospheric windows or all of the L and M windows in a single exposure. GMTNIRS makes use of the GMT adaptive optics system for all bands. The small slits will offer the possibility of spatially resolved spectroscopy as well as superior sensitivity and wavelength coverage. The GMTNIRS team is composed of scientists and engineers at the University of Texas, the Korea Astronomy and Space Science Institute, and Kyung Hee University. In this paper, we describe the optical and mechanical design of the instrument. The principal innovative feature of the design is the use of silicon immersion gratings which are now being produced by our team with sufficient quality to permit designs with high resolving power and broad instantaneous wavelength coverage across the near-IR.

Context. We present far-infrared spectroscopic observations, taken with the Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory, of the protoplanetary disk around the pre-main-sequence star HD 100546. These observations are the first within the DIGIT Herschel key program, which aims to follow the evolution of dust, ice, and gas from young stellar objects still embedded in their parental molecular cloud core, through the final pre-main-sequence phases when the circumstellar disks are dissipated.Aims. Our aim is to improve the constraints on temperature and chemical composition of the crystalline olivines in the disk of HD 100546 and to give an inventory of the gas lines present in its far-infrared spectrum.Methods. The 69 μm feature is analyzed in terms of position and shape to derive the dust temperature and composition. Furthermore, we detected 32 emission lines from five gaseous species and measured their line fluxes.Results. The 69 μm emission comes either from dust grains with ~70 K at radii larger than 50 AU, as suggested by blackbody fitting, or it arises from ~200 K dust at ~13 AU, close to the midplane, as supported by radiative transfer models. We also conclude that the forsterite crystals have few defects and contain at most a few percent iron by mass. Forbidden line emission from [C ii] at 157 μm and [O i] at 63 and 145 μm, most likely due to photodissociation by stellar photons, is detected. Furthermore, five H2O and several OH lines are detected. We also found high-J rotational transition lines of CO, with rotational temperatures of ~300 K for the transitions up to J = 22-21 and T ~ 800 K for higher transitions.

DK Cha is an intermediate-mass star in transition from an embedded configuration to a star plus disk stage. We aim to study the composition and energetics of the circumstellar material during this pivotal stage. Using the Range Scan mode of PACS on the Herschel Space Observatory, we obtained a spectrum of DK Cha from 55 to 210 micron as part of the DIGIT Key Program. Almost 50 molecular and atomic lines were detected, many more than the 7 lines detected in ISO-LWS. Nearly the entire ladder of CO from J=14-13 to 38-37 (E_u/k = 4080 K), water from levels as excited as E_u/k = 843 K, and OH lines up to E_u/k = 290 K were detected. The continuum emission in our PACS SED scan matches the flux expected from a model consisting of a star, a surrounding disk of 0.03 Solar mass, and an envelope of a similar mass, supporting the suggestion that the object is emerging from its main accretion stage. Molecular, atomic, and ionic emission lines in the far-infrared reveal the outflow's influence on the envelope. The inferred hot gas can be photon-heated, but some emission could be due to C-shocks in the walls of the outflow cavity., Comment: 4 Page letter, To appear in A&A special issue on Herschel

We present a mid-infrared high spectral resolution spectrum of CRL618 in the frequency ranges 778-784 and 1227-1249 cm^-1 (8.01-8.15 and 12.75-12.85 um) taken with the Texas Echelon-cross-Echelle Spectrograph (TEXES) and the Infrared Telescope Facility (IRTF). We have identified more than 170 ro-vibrational lines arising from C2H2, HCN, C4H2, and C6H2. We have found no unmistakable trace of C8H2. The line profiles display a complex structure suggesting the presence of polyacetylenes in several components of the circumstellar envelope (CSE). We derive total column densities of 2.5 10^17, 3.1 10^17, 2.1 10^17, 9.3 10^16 cm^-2, and < 5 10^16 cm^-2 for HCN, C2H2, C4H2, C6H2, and C8H2, respectively. The observations indicate that both the rotational and vibrational temperatures in the innermost CSE depend on the molecule, varying from 100 to 350 K for the rotational temperatures and 100 to 500 K for the vibrational temperatures. Our results support a chemistry in the innermost CSE based on radical-neutral reactions triggered by the intense UV radiation field., 9 pages, 4 figures, 1 table; accepted for publication in The Astrophysical Journal

NASA-IRTF observations of Neptune's disk-averaged spectrum are presently used, in conjunction with a lower-resolution spectrum, to furnish a more reliable absolute intensity calibration of portions of Neptune's disk-averaged spectrum. The temperature profile adopted is consistent with the size and shape of the H2 J = 3-1 quadrupole feature detected in the emission. High-resolution measurements of (C-13C-12)H6 and (C-12)2H6 imply C-12/C-13 of 78 +/- 26; this is consistent with solar and telluric values.

The optimal solution for priming cardiopulmonary bypass machines and for postoperative resuscitation following myocardial revascularisation should be inexpensive, free of risk of transmitting disease, and free of other detrimental side effects. Colloid solutions are preferred over crystalloid solutions because of elevations in extracellular sodium and water that occur with cardiopulmonary bypass. Albumin, plasma protein solution, hetastarch (hydroxyethyl starch) and dextran are available for use if blood is not necessary and mediastinal blood is not available. Hetastarch is associated with a lower risk of bleeding and less risk of allergic reaction than dextran, and its cost is substantially less than that of albumin. However, high doses increase the risk of bleeding complications.

Cryogenic echelle grating spectrometry of Comet Austin has been obtained for the p(1) through p(14) line frequencies of the nu3 band of OCS. A 3-sigma upper limit for OCS abundance of 0.0055 is derived, relative to H2O, for an assumed coma temperature of 50 K. This value is intermediate between the IRAM observations of Comet Levy and Vega 1 measurements of P/Halley.

A cryogenic IR echelle grating spectrometer has been used to probe the nu = 1-0 rovibrational band of the CO molecule in Comet Austin. Line emission has been detected at the Doppler-shifted frequency expected for the cometary P(3) line, in scans which are noted to cover only the first 3000 sec of May 16, 1990 observations; this is suggested to be due to an outburst of comparable duration. No detections were made of the P(2) line, which was predicted by models to occur at the 3.5 sigma level even for relatively high coma temperatures. If the outburst was accompanied by enhanced dust production, an increase by a factor of 2.5 is consistent with the present observational data and CO/dust may have been enriched in the outbursting volume relative to the remainder of the nucleus.

We report the results of a search for pure rotational molecular hydrogen emission from the circumstellar environments of young stellar objects with disks using the Texas Echelon Cross Echelle Spectrograph (TEXES) on the NASA Infrared Telescope Facility and the Gemini North Observatory. We searched for mid-infrared H2 emission in the S(1), S(2), and S(4) transitions. Keck/NIRSPEC observations of the H2 S(9) transition were included for some sources as an additional constraint on the gas temperature. We detected H2 emission from 6 of 29 sources observed: AB Aur, DoAr 21, Elias 29, GSS 30 IRS 1, GV Tau N, and HL Tau. Four of the six targets with detected emission are class I sources that show evidence for surrounding material in an envelope in addition to a circumstellar disk. In these cases, we show that accretion shock heating is a plausible excitation mechanism. The detected emission lines are narrow (~10 km/s), centered at the stellar velocity, and spatially unresolved at scales of 0.4 arcsec, which is consistent with origin from a disk at radii 10-50 AU from the star. In cases where we detect multiple emission lines, we derive temperatures > 500 K from ~1 M_earth of gas. Our upper limits for the non-detections place upper limits on the amount of H2 gas with T > 500 K of less than a few Earth masses. Such warm gas temperatures are significantly higher than the equilibrium dust temperatures at these radii, suggesting that the gas is decoupled from the dust in the regions we are studying and that processes such as UV, X-ray, and accretion heating may be important., 24 pages, 16 figures, 5 tables, ApJ accepted

TEXES is a high resolution mid-infrared spectrograph acting as a visiting instrument at the NASA IRTF and Gemini North telescopes. Switching from high (R=100,000) to medium resolution (R=15,000), the noise becomes detector dominated due to charge cascades in the low-background detector. This is remedied by lowering the bias voltage across the detector, a problem during observing runs as it requires manual adjustment within the electronics. To save telescope time, a bias selector has been created to allow the bias voltage to be switched from the control room between four options. The options were chosen based upon signal to noise vs. bias voltage testing.

We present high resolution (R = 90,000) mid-infrared spectra of M dwarfs. The mid infrared region of the spectra of cool low mass stars contain pure rotational water vapour transitions that may provide us with a new methodology in the determination of the effective temperatures for low mass stars. We identify and assign water transitions in these spectra and determine how sensitive each pure rotational water transition is to small (25 K) changes in effective temperature. We find that, of the 36 confirmed and assigned pure rotational water transitions, at least 10 should be sensitive enough to be used as temperature indicators., accepted by MNRAS

We present high spatial and spectral resolution observations of sixteen Galactic compact and ultracompact H II regions in the [Ne II] 12.8 microns fine structure line. The small thermal width of the neon line and the high dynamic range of the maps provide an unprecedented view of the kinematics of compact and ultracompact H II regions. These observations solidify an emerging picture of the structure of ultracompact H II regions suggested in our earlier studies of G29.96-0.02 and Mon R2 IRS1; systematic surface flows, rather than turbulence or bulk expansion, dominate the gas motions in the H II regions. The observations show that almost all of the sources have significant (5-20 km/s) velocity gradients and that most of the sources are limb-brightened. In many cases, the velocity pattern implies tangential flow along a dense shell of ionized gas. None of the observed sources clearly fits into the categories of filled expanding spheres, expanding shells, filled blister flows, or cometary H II regions formed by rapidly moving stars. Instead, the kinematics and morphologies of most of the sources lead to a picture of H II regions confined to the edges of cavities created by stellar wind ram pressure and flowing along the cavity surfaces. In sources where the radio continuum and [Ne II] morphologies agree, the majority of the ionic emission is blue-shifted relative to nearby molecular gas. This is consistent with sources lying on the near side of their natal clouds being less affected by extinction and with gas motions being predominantly outward, as is expected for pressure-driven flows., Comment: 79 pages, 48 figures, 2 tables, accepted for publication in The Astrophysical Journal Supplement. The orders of figure 47 and 48 are corrected

We present observations of pure rotational molecular hydrogen emission from the Herbig Ae star, AB Aurigae. Our observations were made using the Texas Echelon Cross Echelle Spectrograph (TEXES) at the NASA Infrared Telescope Facility and the Gemini North Observatory. We searched for H2 emission in the S(1), S(2), and S(4) lines at high spectral resolution and detected all three. By fitting a simple model for the emission in the three transitions, we derive T = 670 +/- 40 K and M = 0.52 +/- 0.15 earth masses for the emitting gas. Based on the 8.5 km/s FWHM of the S(2) line, assuming the emission comes from the circumstellar disk, and with an inclination estimate of the AB Aur system taken from the literature, we place the location for the emission near 18 AU. Comparison of our derived temperature to a disk structure model suggests that UV and X-ray heating are important in heating the disk atmosphere., 4 pages using emulateapj, 2 figures, ApJL accepted

We have mapped [Ne II] (12.8um) and [S IV] (10.5um) emission from W51 IRS 2 with TEXES on Gemini North, and we compare these data to VLA free-free observations and VLT near-infrared images. With 0.5" spatial and 4 km/s spectral resolution we are able to separate the ionized gas into several components: an extended H II region on the front surface of the molecular cloud, several embedded compact H II regions, and a streamer of high velocity gas. We interpret the high velocity streamer as a precessing or fan-like jet, which has emerged from the molecular cloud into an OB star cluster where it is being ionized., Comment: 3 pages, 4 figures, 2 movies

We present radio and infrared observations indicating on-going star formation activity inside the $\sim2-5$ pc circumnuclear ring at the Galactic center. Collectively these measurements suggest a continued disk-based mode of on-going star formation has taken place near Sgr A* over the last few million years. First, VLA observations with spatial resolution 2.17$"\times0.81"$ reveal 13 water masers, several of which have multiple velocity components. The presence of interstellar water masers suggests gas densities that are sufficient for self-gravity to overcome the tidal shear of the 4$\times10^6$ \msol\, black hole. Second, SED modeling of stellar sources indicate massive YSO candidates interior to the molecular ring, supporting in-situ star formation near Sgr A* and appear to show a distribution similar to that of the counter-rotating disks of $\sim$100 OB stars orbiting Sgr A*. Some YSO candidates (e.g., IRS~5) have bow shock structures suggesting that they have have gaseous disks that are phototoevaporated and photoionized by the strong radiation field. Third, we detect clumps of SiO (2-1) and (5-4) line emission in the ring based on CARMA and SMA observations. The FWHM and luminosity of the SiO emission is consistent with shocked protostellar outflows. Fourth, two linear ionized features with an extent of $\sim0.8$ pc show blue and redshifted velocities between $+50$ and $-40$ \kms, suggesting protostellar jet driven outflows with mass loss rates of $\sim5\times10^{-5}$ solar mass yr$^{-1}$. Finally, we present the imprint of radio dark clouds at 44 GHz, representing a reservoir of molecular gas that feeds star formation activity close to Sgr A*., 38 pages, 10 figures, ApJ (in press)

A feasibility design study was undertaken to assess the requirements of a mid-infrared echelle spectrograph (MIRES) with a resolving power of 120,000 and its associated mid-infrared adaptive optics (MIRAO) system on the Thirty-Meter Telescope. Our baseline design incorporates a 2K×2K Si:As array or array mosaic for the spectrograph and a 1K×1K Si:As array for the slit viewer. Various tradeoffs were studied to minimize risk and to optimize the sensitivity of the instrument. Major challenges are to integrate the spectrograph to the MIRAO system and, later, to an adaptive secondary, the procurement of a suitable window and large KRS-5 lenses, and the acquisition of large format mid-IR detector arrays suitable for the range of background conditions. We conclude that the overall risk is relatively low and there is no technical reason that should prevent this instrument from being ready for use at first light on the Thirty- Meter Telescope.

The Echelon-cross-Echelle Spectrograph (EXES) will provide the Stratospheric Observatory for Infrared Astronomy (SOFIA) with high spectral resolution capabilities in the mid-infrared. EXES will have a maximum spectral resolving power of 100,000 along with lower resolution options (R=10,000; R=3000). EXES on SOFIA will provide sensitivity and spectral resolution never before available from an orbital or sub-orbital platform. Because of the wealth of molecular features in the EXES spectral range, 4.5 to 28.3 μm, and the dramatic reduction in telluric atmospheric interfence provided by SOFIA, EXES will be particularly relevant for studies of the solar system, star formation and the interstellar medium. We report on the EXES design and current status, provide descriptions of observing modes and sensitivity estimates, discuss the calibration and likely data products, and describe the potential gains of incorporating a 1024 × 1024, low-background, Si:As detector array.

TEXES is a versatile mid-infrared spectrograph, which has been used on the NASA IRTF since 2000. It is capable of high spectral resolution (R ≈ 100,000), which is well suited for observations of interstellar and circumstellar molecules and ions, as well as molecules in planetary and stellar atmospheres. It has been installed on Gemini North where its point source sensitivity is expected to improve by a factor of 7, and its angular resolution will improve by 8/3.

We present a discussion of the science drivers and design approach for a high-resolution, mid-infrared spectrograph for the Thirty-Meter Telescope. The instrument will be integrated with an adaptive optics system optimized for the midinfrared; as a consequence it is not significantly larger or more complex than similar instruments designed for use on smaller telescopes. The high spatial and spectral resolution possible with such a design provides a unique scientific capability. The design provides spectral resolution of up to 120,000 for the 4.5-25 �� m region in a cross-dispersed format that provides continuous spectral coverage of up to 2% to 14 �� m. The basic concept is derived from the successful TEXES mid-infrared spectrograph. To facilitate operation, there are separate imaging channels for the near-infrared and the mid-infrared; both can be used for acquisition and the mid-infrared imaging mode can be used for science imaging and for guiding. Because the spectrograph is matched to the diffraction limit of a 30-m telescope, gains in sensitivity are roughly proportional to the square of the telescope diameter, opening up a volume within the Galaxy a thousand times greater than existing instruments.

1 Department of Astronomy, University of Texas at Austin, Austin, TX 78712-0259 2 Department of Physics, University of California, Davis, 1 Shields Avenue, Davis, CA 95616 3 Visiting Astronomer at the Infrared Telescope Facility, which is operated by the University of Hawaii under Cooperative Agreement no. NCC 5-538 with the National Aeronautics and Space Administration, Office of Space Science, Planetary Astronomy Program.

We describe the TEXES survey for mid-IR H2 pure rotational emission from young stars and report early successes. H2 emission is a potential tracer of warm gas in circumstellar disks. Three pure rotational lines are available from the ground: the J=3=>1, J=4=>2, and J=6=>4, transitions at 17.035 microns, 12.279 microns, and 8.025 microns, respectively. Using TEXES at the NASA IRTF 3m, we are midway through a survey of roughly 30 pre-main-sequence stars. To date, detected lines are all resolved, generally with FWHM

Ultracompact HII regions are signposts of massive star formation and their properties provide diagnostics for the characteristics of very young O stars embedded in molecular clouds. While radio observations have given us a good picture of the morphology of these regions, they have not provided clear information about the kinematics. Using high spectral resolution observations of the 12.8 micron [NeII] line, it has been possible for the first time to trace the internal kinematics of several ultracompact HII regions. We find that the motions in the cometary ultracompact HII regions MonR2 and G29.96-0.02 are highly organized. The velocity patterns are consistent with parabolic ionized flows along a neutral boundary layer.

PUBLISHED, The outer atmosphere of the M supergiant Betelgeuse is puzzling. Published observations of different kinds have shed light on different aspects of the atmosphere, but no unified picture has emerged. They have shown, for example, evidence of a water envelope (MOLsphere) that in some studies is found to be optically thick in the mid-infrared. In this paper, we present high-resolution, mid-infrared spectra of Betelgeuse recorded with the TEXES spectrograph. The spectra clearly show absorption features of water vapor and OH. We show that a spectrum based on a spherical, hydrostatic model photosphere with Teff = 3600 K, an effective temperature often assumed for Betelgeuse, fails to model the observed lines. Furthermore, we show that published MOLspheres scenarios are unable to explain our data. However, we are able to model the observed spectrum reasonably well by adopting a cooler outer photospheric structure corresponding to Tmod = 3250 K. The success of this model may indicate the observed mid-infrared lines are formed in cool photospheric surface regions. Given the uncertainties of the temperature structure and the likely presence of inhomogeneities, we cannot rule out the possibility that our spectrum could be mostly photospheric, albeit non-classical. Our data put new, strong constraints on atmospheric models of Betelgeuse and we conclude that continued investigation requires consideration of non-classical model photospheres as well as possible effects of a MOLsphere. We show that the mid-infrared water-vapor features have great diagnostic value for the environments of K and M (super-) giant star atmospheres., NR would like to thank B. Plez and E. Josselin for fruitful discussions and their hospitality during his stay at GRAAL in Montpellier. We gratefully acknowledge the suggestions made by Bengt Gustafsson and Kjell Eriksson for improvements to the paper. We are grateful for the help of the TEXES team as well as the IRTF staff. The use of TEXES is supported by the National Science Foundation (NSF) grant AST-0205518 and by the Texas Advanced Research Program. NR received some financial support from the Swedish Research Council and GMH?s contribution was supported by the NASA ADP Grant No. NNG04GD33G issued through the Office of Space Science and the NSF US-Sweden Cooperative Research Program grant INT-0318835 to the University of Colorado. MJR received some financial support from the NSF (grant AST-0307497) and NASA (grant NNG04GG92G). TG received support from the Lunar and Planetary Institute, which is operated by the Universities Space Research Association under NASA CAN-NCC5-679. JL was supported by NSF grant AST-0205518.

A mid-infrared high-resolution spectral survey of the source IRC+10216 (CW Leo) has been carried out between 11 and 14 $\mu$ m. A large number of lines of C $_2$ H $_2$ and HCN and their most abundant isotopologues, have been identified. Lines involving high-energy ro-vibrational levels allow an accurate derivation of the physical and chemical conditions in the innermost envelope. We have developed a radiative transfer model capable of fitting the observed lines satisfactorily. The fit of more than 200 ro-vibrational lines allowed us to get the kinetic, vibrational and rotational temperatures and the abundances of the C $_2$ H $_2$ and HCN between 1 and 300 R $_*$ .

Hydrogen peroxide (H2O2) has been suggested as a possible oxidizer of the martian surface. Photochemical models predict a mean column density in the range of 1015–1016 cm−2. However, a stringent upper limit of the H2O2 abundance on Mars (9×1014 cm−2) was derived in February 2001 from ground-based infrared spectroscopy, at a time corresponding to a maximum water vapor abundance in the northern summer (30 pr. μm, Ls=112°). Here we report the detection of H2O2 on Mars in June 2003, and its mapping over the martian disk using the same technique, during the southern spring (Ls=206°) when the global water vapor abundance was ∼10 pr. μm. The spatial distribution of H2O2 shows a maximum in the morning around the sub-solar latitude. The mean H2O2 column density (6×1015 cm−2) is significantly greater than our previous upper limit, pointing to seasonal variations. Our new result is globally consistent with the predictions of photochemical models, and also with submillimeter ground-based measurements obtained in September 2003 (Ls=254°), averaged over the martian disk (Clancy et al., 2004, Icarus 168, 116–121)

We present the first results of a study of the kinematics and morphology of ultracompact HII regions using a new observational technique. We used very high spatial (1.5") and spectral (3.4 km/s)resolution observations of the [NeII] line at 12.8 microns to study the ionized gas in Monoceros R2. The [NeII] emission shows an HII region with highest emission measure in a ~24" shell. Line widths are as narrow as 8 km/s at some positions. In places where the lines are complex and broader, the additional width is most likely due to overlap of narrower features along the line of sight. The global kinematics suggest that the 24" shell is expanding at ~10 km/s. However, the spectral profiles toward the southeast side of the shell are not consistent with a simple expansion picture., 25 pages, 7 figures

TEXES, the Texas Echelon Cross Echelle Spectrograph, is an ideal instrument to study molecular clouds at a spectral resolving power of 100,000 between 5 and 25 μm. In many molecular clouds, high extinction often means that no visible stars are available for off-axis guiding. At a resolving power of 100,000, only the very brightest sources can be observed while guiding on the power in the dispersed IR spectra. We present the design of a high-speed on-axis guider for TEXES operating at 3.65 μm, a wavelength outside the spectrometer operating band where many of the target sources are still detectable for imaging. We use a new technology gold nanomesh resonant IR filter/mirror from EDTEK, that transmits 3.65 μm light to the guide detector with a peak transmittance of 60% while reflecting light from 5 μm long-ward with 98% efficiency to the dispersing elements in the spectrograph. A PC controls clocking patterns for the CRC-463 detector from Raytheon Infrared Operations and the analog to digital conversion of signals with a 14 bit A/D card. Image centroiding is done in software and then offsets are sent to the telescope for pointing adjustments or tip-tilt corrections when a tip-tilt secondary is available. This system is a prototype designed to test the feasibility of a similar guider for EXES, the Echelon Cross Echelle Spectrograph, mounted on SOFIA, the Stratospheric Observatory for Infrared Astronomy.

TEXES, the Texas Echelon Cross Echelle Spectrograph, is a versatile mid-infrared (5-25 μm) spectrograph that can be used in several operating modes: high resolution cross-dispersed, with a resolving power of R = 50-100,000; medium resolution long-slit, with R~15,000; low resolution long-slit, with R~3000; source acquisition imaging; and pupil imaging. The design of TEXES is unique in several respects. The primary disperser is a variation on an echelon, a steeply and coarsely blazed (R10 with 0.3 inch groove spacing), 36 inch long, diamond-machined aluminum grating. The cross disperser is an R4 echelle used in low order at R2, with the grooves acting as corner reflectors. Cold mechanisms allow the echelon to be bypassed to use the cross disperser in long-slit mode. A first-order grating can be inserted in front of the echelle for lower resolution. In addition, the low resolution grating can be turned face-on to act as a mirror allowing source-acquisition imaging and pupil viewing. TEXES has been used for 8 nights on the McDonald Observatory 2.7m and 45 nights on the NASA IRTF 3m telescopes over the last 2 1/2 years. Sources observed include planets and planetary satellites, stellar atmospheres, circumstellar outflows and disks, and molecular clouds and HII regions in the Milky Way and external galaxies.

The Stratospheric Observatory for Infrared Astronomy (SOFIA) will provide new opportunities for high spectral resolution observations in the mid-infrared. To take advantage of these opportunities, we are developing EXES, the Echelon-Cross-Echelle Spectrograph. EXES will operate from 4.5 microns to 28.5 microns and achieve a velocity resolution of 3 km/s for λ < 10 μm. EXES will be a versatile instrument with three spectroscopic modes: cross-dispersed with R~105; long-slit with R~104; and long-slit with R~3000. The unique aspect of EXES is the high-resolution capability provided by a 1 meter echelon grating and a 256 by 256 low-background Si:As IBC detector. Much of the design and operation of EXES has already been validated by the performance of a very similar ground-based instrument, the Texas Echelon-Cross-Echelle Spectrograph (TEXES). We present here a summary of the EXES design and current status; a brief description of ground-based, high spectral resolution, mid-infrared results; and a look ahead to the possible science using SOFIA and EXES.

Here, we report on our detection of water vapor in the mid-infrared (11-12 microns) spectrum of the Kl.5 giant Arcturus (α Boo) obtained with the high-resolution, infrared spectrograph TEXES. The detection is presented in detail in Ryde et al. 2002 ApJ, submitted. We are successful in modeling several resolved, rotational lines of water vapor and vibration-rotational (1.5 microns) and rotational lines of OH with a modified MARCS photosphere

We present the first observations of propane (C$_3$H$_8$) on Titan that unambiguously resolve propane features from other numerous stratospheric emissions. This is accomplished using a $R=\lambda/\delta\lambda\approx10^5$ spectrometer (TEXES) to observe propane's $\nu_{26}$ rotation-vibration band near 748 cm$^{-1}$. We find a best-fit fractional abundance of propane in Titan's stratosphere of $(6.2\pm1.2)\times10^{-7}$ in the altitude range to which we are sensitive (90-250 km or 13-0.24 mbar)., Comment: accepted to ApJL 18 September 2003; See also: http://www.gps.caltech.edu/~hroe/propane2003/

Hydrogen peroxide H2O2 has been suggested as a possible oxidizer of the Martian surface. However, this minor species has never been detected. Photochemical models suggest that H2O2 and H2O abundances should be correlated. We have searched for H2O2 in the northern atmosphere of Mars, on Feb. 2-3, 2001 (Ls= 112 deg), at a time corresponding to maximum water vapor abundance in the northern hemisphere. The TEXES high-resolution grating spectrograph was used at the NASA/Infrared Telescope Facility (IRTF). Individual lines of the H2O26 band were searched for in the 1226-1235 cm 1

We discuss the design and performance of TEXES, the Texas Echelon Cross Echelle Spectrograph. TEXES is a mid-infrared (5-25 um) spectrograph with several operating modes: high-resolution, cross-dispersed with a resolving power of R=100,000, 0.5% spectral coverage, and a ~1.5 by 8" slit; medium-resolution long-slit with R~15,000, 0.5% coverage, and a ~1.5 by 45" slit; low-resolution long-slit with (delta lambda)~0.004 um, 0.25 um coverage, and a ~1.5 by 45" slit; and source acquisition imaging with 0.33" pixels and a 25 by 25" field of view on a 3m telescope. TEXES has been used at the McDonald Observatory 2.7m and the IRTF 3m telescopes, and has proven to be both sensitive and versatile., 33 pages, 11 figures. Accepted to PASP. For slightly better, color versions of Figs 1-3, see http://nene.as.utexas.edu/richter/texes/pasp

We present infrared spectra of four embedded protostars in the 750-1230 cm-1 (13.3-8.1 microns) range. For NGC 7538 IRS 9, a new band is reported at 1110 cm-1 (9.01 microns, and several others may be present near 785, 820, 900, 1030, and 1075 cm-1 (12.7, 12.2, 11.1, 9.71, and 9.30 microns). The band 1110 cm-1 is attributed to frozen NH3. Its position and width imply that the NH3 is frozen in a polar, H2O-rich interstellar ice component. The NH3/H2O ice ratio inferred for NGC 7538 IRS 9 is 0.1, making NH3 as important a component as CH3OH and CO2 in the polar ices along this line of sight. At these concentrations, hydrogen bonding between the NH3 and H2O can account for much of the enigmatic low-frequency wing on the 3240 cm-1 (3.09 microns) H2O interstellar ice band. The strength of the implied NH3 deformation fundamental at 1624 cm-1 (6.158 microns) can also account for the absorption at this position reported by ISO.

We are developing a high spectral resolution grating spectrograph as a PT instrument for the Stratospheric Observa-tory for Infrared Astronomy (SOFIA). The Echelon-Cross-Echelle Spectrograph (EXES) will operate at 5.5-28.5 pm in three spectroscopic modes: R iO, 2 x i04, and 4000. We use an echelon, a coarsely ruled, steeply blazeddiffraction grating to achieve high resolution. Cross-dispersion is done with an echelle used at relatively low order.The detector is a 256 x 256 pixel Si:As IBC array. A very similar instrument, the Texas Echelon-Cross-EchelleSpectrograph (TEXES), has had a successful telescope run at the McDonald Observatory. We give here a progressreport on the design of EXES and the status of TEXES.Keywords: Infrared, Spectrograph, SOFIA 1. INTRODUCTION Molecules provide the best tracers of the changes in density, temperature, bulk velocity, and chemical state asdiffuse clouds become stars with disks and planets. Our current picture of star formation has benefited greatly

To study narrow features in quiescent molecular clouds, a high spectral resolution, high sensitivity instrument is required. We present the design and capabilities of a mid-IR spectrograph being built as a PI instrument for the Stratospheric Observatory for IR Astronomy. The Echelon- Cross-Echelle Spectrograph (EXES) will operate from 5.5-28.5 micrometers in three spectroscopic modes: R approximately 105, 104, and 1500. EXES is similar in concept to our ground based instrument, TEXES. EXES consists of three chambers. The first chamber contains focal-reducing optics. The second chamber houses the high resolution grating, an echelon. Discussion of the echelon can be found elsewhere in this volume. The third chamber contains an echelle grating and a first order grating mounted back-to-back. A flip mirror selects operating mode by either directing light into the echelon chamber or allowing the light to pass through to the grating chamber. Re-imaging optics upstream of the detector provide two plate scales. The detector, a 256 by 256 pixel Si:As IBC, is in a baffled subsection of the third chamber. Finally, the low resolution grating serves as a slit positioning camera when it is rotated face on.

A new mid-IR spectrograph, the Texas Echelon Cross Echelle Spectrograph (TEXES) is under construction. The primary motivation for TEXES is to observe interstellar molecules at very high resolution. TEXES will operate at 7-25 micrometers wavelength with three spectrographic modes: a high resolution cross-dispersed mode, with R approximately equals 100,000, a mid-resolution long-slit mode, with R approximately equals 14,000, and a low resolution long-slit mode, with R approximately equals 2000. In hi-res mode, the primary disperser is a 36 inch long, R10 grating with a 7 mm groove spacing. The echelon is cross-dispersed with a 7 in long R2 echelle. In mid-res mode, the echelon is by-passed with an Offner relay, and the echelle is used by itself. In lo-res mode, a first-order grating is inserted over the echelle. For initial test, TEXES will use a Hughes Aircraft 20 X 64 pixel Si:As impurity-band array, which covers only two echelon orders. It will later be replaced with a 256 X 256 pixel array, which will Nyquist sample approximately 10 orders. The spectrograph has been assembled and tested with a partially complete echelon, demonstrating the soundness of the design. When we began this project, we were unable to find a vendor capable of machining or ruling a diffraction grating with the very coarse ruling required. Consequently, we attempted to hand-fabricate the echelon. We have not succeeded in assembling the echelon with the required precision, missing by about a factor of two. Fortunately, Hyperfine, Inc. is now capable of diamond machining the echelon. We are purchasing a machined echelon, and hope to complete the spectrograph by the end of summer 1998.

We have obtained near-infrared images and mid-infrared spectra of the starburst core of the dwarf Wolf-Rayet galaxy He 2-10. We find that the infrared continuum and emission lines are concentrated in a flattened ellipse 3-4'' or 150 pc across which may show where a recent accretion event has triggered intense star formation. The ionizing radiation from this cluster has an effective temperature of 40,000 K, corresponding to $30M_\odot$ stars, and the starburst is $0.5-1.5 \times 10^7$ years old., 17 pages Latex, 7 postscript figures, 1 postscript table, accepted to AJ

Sulfur dioxide and water vapor, two key species of Venus photochemistry, are known to exhibit significant spatial and temporal variations above the cloud top. In particular, ground-based thermal imaging spectroscopy at high spectral resolution, achieved on Venus in January 2012, has shown evidence for strong SO2 variations on timescales shorter than a day. We have continued our observing campaign using the TEXES high-resolution imaging spectrometer at the NASA InfraRed Telescope Facility to map sulfur dioxide over the disk of Venus at two different wavelengths, 7 μm (already used in the previous study) and 19 μm. The 7 μm radiation probes the top of the H2SO4 cloud, while the 19 μm radiation probes a few kilometers below within the cloud. Observations took place on October 4 and 5, 2012. Both HDO and SO2 lines are identified in our 7-μm spectra and SO2 is also easily identified at 19 μm. The CO2 lines at 7 and 19 μm are used to infer the thermal structure. An isothermal/inversion layer is present at high latitudes (above 60 N and S) in the polar collars, which was not detected in October 2012. The enhancement of the polar collar in October 2012 is probably due to the fact that the morning terminator is observed, while the January data probed the evening terminator. As observed in our previous run, the HDO map is relatively uniform over the disk of Venus, with a mean mixing ratio of about 1 ppm. In contrast, the SO2 maps at 19 μm show intensity variations by a factor of about 2 over the disk within the cloud, less patchy than observed at the cloud top at 7 μm. In addition, the SO2 maps seem to indicate significant temporal changes within an hour. There is evidence for ac utoff in the SO2 vertical distribution above the cloud top, also previously observed by SPICAV/SOIR aboard Venus Express and predicted by photochemical models.

A few diatomic interstellar molecules (CH, CN, and CH+) were detected in 1937–1940 with optical spectroscopy [1, 2, 3]. After a long delay, another diatomic (OH) was discovered at radio wavelengths in 1963 [4]. Despite these early results and the publication of lists of other candidate molecules by Townes [5] and Shklovsky [6], further progress awaited the development of radio telescopes and receivers working at higher frequencies. The discovery of ammonia (NH3) and H20 in 1968–1969 by the group at Berkeley [7, 8], followed by the discovery of formaldehyde (H2CO) [9], opened the floodgates. By 1995, about 100 molecules have been discovered in space, mostly with radio frequency spectroscopy of rotational transitions.

We present the first observation of the pure rotational 0-0 S(2) line of H2, at 12.28 μm, from the supernova remnant IC 443. In combination with near infrared observations, the pure rotational emission effectively differentiates between broad classes of shock model. A J-shock, in which H2 is partially dissociated, propagating into gas with H2 density of 4 × 103 cm-3 provides a good fit to the observed H2 level populations but cannot be reconciled with the shock velocity inferred from H2 line profiles. The relative H2 level population in IC 443 and Orion Peak 1, discovered to be essentially identical for upper state energies E/k > 6000 K by Richter, Graham, and Wright, is identical for the 0-0 S(2) line at E/k = 1681.6 K, suggesting that the underlying nature of the two shocks as traced by H2 observations is identical.

We present accurate new wavenumbers for a set of 13 mid-infrared fine-structure lines. The wavenumbers were determined from observations of the planetary nebula NGC 7027 and of the red supergiant Alpha Scorpii. Most of the new wavenumbers are good to within 0.0025%, or 8 km/s. We provide details on the measurements and present an analysis of the errors. In addition, we present the first observations of hyperfine splitting in the [Na IV] 1106 cm-1 line., Comment: 12 pages text, 2 postscript figures, uses AASTeX macros, figures are gzipped and uuencoded