Detection of solid ammonia, methanol, and methane with ISOPHOT

Gürtler, J.; Klaas, U.; Henning, Th.; Ábrahám, P.; Lemke, D.; Schreyer, K.; Lehmann, K. K.

doi:10.1051/0004-6361:20020772

Cited by 52 publications

(57 citation statements)

References 23 publications

(42 reference statements)

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“…The upper limit of the ratio of C 2 H 6 ice to CH 4 ice in NGC 7538 IRS 9 is considerably smaller than the ratio obtained in comet 153P/Ikeya-Zhang. The abundance of ethane ice to water ice in NGC 7538 IRS 9 is less than 0.4%, which is comparable to the value observed in the comet, and the relative abundance of methane ice to water ice in the interstellar medium (1%-2% at best) is slightly higher than the cometary value obtained here (Boudin et al 1998;Gü rtler et al 2002). If the upper limits of ethane ice in NGC 7538 IRS 9 are typical in the interstellar medium, there are two possible mechanisms for realizing these facts.…”

Section: Relative Abundance Of Ethane To Methane and Formation Conditsupporting

confidence: 58%

Saturated Hydrocarbons in Comet 153P/Ikeya‐Zhang: Ethane, Methane, and Monodeuterio‐Methane

Kawakita¹,

Watanabe²,

Kinoshita³

et al. 2003

ApJ

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Emissions of the methane 3 band and the ethane 7 band were detected in the high-dispersion infrared spectra of comet 153P/Ikeya-Zhang taken by the Subaru Telescope with the Infrared Camera and Spectrograph (IRCS) on 2002 May 28 and 29 UT. The rotational temperature is estimated to be about 40-50 K from R 0 and R 1 lines of the methane 3 band. The production rates of methane and ethane were estimated by applying the rotational temperature of 50 K. Resultant production rates of methane and ethane are ð2:13 AE 0:40Þ Â 10 26 and ð1:75 AE 0:48Þ Â 10 26 molecules s À1 , respectively. The abundance ratio between ethane and methane is 0:82 AE 0:27, which is comparable with other comets within error bars. Although the emissions of monodeuterio-methane (CH 3 D) were searched for carefully, there is no evidence of them. The 2 (95% confidence) upper limit of the CH 3 D/CH 4 ratio is 0.3 in comet 153P/Ikeya-Zhang. Comparing the relative abundance of methane and ethane in the interstellar ices, we discussed the formation conditions of cometary nuclei.

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Section: Relative Abundance Of Ethane To Methane and Formation Conditsupporting

confidence: 58%

Saturated Hydrocarbons in Comet 153P/Ikeya‐Zhang: Ethane, Methane, and Monodeuterio‐Methane

Kawakita¹,

Watanabe²,

Kinoshita³

et al. 2003

ApJ

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“…It should be noted that the line of sight abundances of CH 3 OH and CO 2 is ∼5-10 times lower than the abundances found close to the protostellar sources due to the dominance of H 2 O ice in the cold outer regions (Gerakines et al 1999). It was recently shown that, contrary to earlier views (Gibb et al 2001;Gürtler et al 2002), most of the ammonia in IS ices is probably present in the form of the ammonium ion, NH + 4 , rather than as NH 3 (Taban et al 2003;Schutte & Khanna 2003). In this paper, however, NH 3 is used as a component of the starting ice mixture.…”

Section: Introductionmentioning

confidence: 77%

UV-photoprocessing of interstellar ice analogs: New infrared spectroscopic results

Muñoz

Schütte

2003

A&A

163

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Abstract. We simulate experimentally the physical conditions present in dense clouds by means of a high vacuum experimental setup at low temperature T ≈ 12 K. The accretion and photoprocessing of ices on grain surfaces is simulated in the following way: an ice layer with composition analogous to that of interstellar ices is deposited on a substrate window, while being irradiated by ultraviolet (UV) photons. Subsequently the sample is slowly warmed up to room temperature; a residue remains containing the most refractory products of photo-and thermal processing. In this paper we report on the Fourier transform-infrared (FT-IR) spectroscopy of the refractory organic material formed under a wide variety of initial conditions (ice composition, UV spectrum, UV dose and sample temperature). The refractory products obtained in these experiments are identified and the corresponding efficiencies of formation are given. The first evidence for carboxylic acid salts as part of the refractory products is shown. The features in the IR spectrum of the refractory material are attributed to hexamethylenetetramine (HMT, [(CH 2 ) 6 N 4 ]), ammonium salts of carboxylic acids [(R-COO − )(NH + )], amides [H 2 NC(=O)-R], esters [R-C(=O)-O-R ] and species related to polyoxymethylene (POM, [(-CH 2 O-) n ]). Furthermore, evidence is presented for the formation of HMT at room temperature, and the important role of H 2 O ice as a catalyst for the formation of complex organic molecules. These species might also be present in the interstellar medium (ISM) and form part of comets. Ongoing and future cometary missions, such as Stardust and Rosetta, will allow a comparison with the laboratory results, providing new insight into the physico-chemical conditions present during the formation of our solar system.

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“…The Glass I system was originally considered a field star because Hα emission was not detected (Glass 1979), but then Feigelson & Kriss (1989) The silicate emission in Glass Ib is variable as well. This was first recognized by Gürtler et al (1999), with the 10 μm flux decreasing by a factor of 2 between 1996 February and 1997 July. Natta et al (2000) observed the system at an intermediate time between those observations in their study of silicate emission from YSOs.…”

Section: Emissionmentioning

confidence: 87%

“…If the shell expands on the order of 20-30 km s −1 , this peak transition from the 10 μm silicate to longer wavelengths occurs over the period of just a few years (Volk & Kwok 1989;Volk 1992). However, the silicate emission has been seen reported toward Glass Ib as early as 1996 February (Gürtler et al 1999). If the dust is in an expanding shell, the continuum would be expected to show stronger infrared excess as opposed to still being similar to Infrared Astronomical Satellite (IRAS) observations (see Figure 6).…”

Section: Planetary Nebulamentioning

confidence: 99%

The Curious Case of Glass I: High Ionization and Variability of Different Types

Kruger

Richter

Carr

et al. 2013

ApJ

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Our Spitzer IRS observation of the infrared companion Glass Ib revealed fine-structure emission with high ionization ([Ne iii]/[Ne ii] = 2.1 and [S iv]/[S iii] = 0.6) that indicates that the gas is likely illuminated by hard radiation. While models suggest that extreme-ultraviolet radiation could be present in T Tauri stars, this is the first detection of [S iv] and such a high [Ne iii]/[Ne ii] ratio in a young star. We also find that Glass Ib displays the molecules HCN, CO 2 , and H 2 O in emission. Here we investigate the Glass I binary system and consider possible mechanisms that may have caused the high ionization, whether from an outflow or disk irradiation. We also model the spectral energy distributions of Glass Ia and Ib to test if the system is a young member of the Chameleon I star-forming region, and we consider other possible classifications for the system. We find that Glass Ib is highly variable, showing changes in continuum strength and emission features at optical, near-infrared, and mid-infrared wavelengths. The optical light curve indicates that a central stellar component in Glass Ib became entirely visible for 2.5 years beginning in mid-2002 and possibly displayed periodic variability with repeated, short-period dimming during that time. As the fine-structure emission was not detected in observations before or after our Spitzer IRS observation, we explore whether the variable nature of Glass Ib is related to the gas being highly ionized, possibly due to variable accretion or an X-ray flare.

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Detection of solid ammonia, methanol, and methane with ISOPHOT

Cited by 52 publications

References 23 publications

Saturated Hydrocarbons in Comet 153P/Ikeya‐Zhang: Ethane, Methane, and Monodeuterio‐Methane

Saturated Hydrocarbons in Comet 153P/Ikeya‐Zhang: Ethane, Methane, and Monodeuterio‐Methane

UV-photoprocessing of interstellar ice analogs: New infrared spectroscopic results

The Curious Case of Glass I: High Ionization and Variability of Different Types

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