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1.
Nicolas Thomas 《紫金山天文台台刊》1996,(3)
Amajor objective of the Infrared Space Observatory (ISO) is the determination of the sized and albedoes of several objects in the "Kuiper disc".The method by which this will be achieved is described.It is shown that the unknown shapes and surface thermal properties proviede additional complications to the interpretation of ISO data.The requirement for ground-based measurements of the visual light curves of these objects is demonstrated and the implications of the results of the ISO observ Vations is discussed. 相似文献
2.
《Planetary and Space Science》1999,47(10-11):1225-1242
Infrared spectra of Jupiter and Saturn have been recorded with the two spectrometers of the Infrared Space Observatory (ISO) in 1995–1998, in the 2.3–180 μm range. Both the grating modes (R=150–2000) and the Fabry-Pérot modes (R=8000–30,000) of the two instruments were used. The main results of these observations are (1) the detection of water vapour in the deep troposphere of Saturn; (2) the detection of new hydrocarbons (CH3C2H, C4H2, C6H6, CH3) in Saturn’s stratosphere; (3) the detection of water vapour and carbon dioxide in the stratospheres of Jupiter and Saturn; (4) a new determination of the D/H ratio from the detection of HD rotational lines. The origin of the external oxygen source on Jupiter and Saturn (also found in the other giant planets and Titan in comparable amounts) may be either interplanetary (micrometeoritic flux) or local (rings and/or satellites). The D/H determination in Jupiter, comparable to Saturn’s result, is in agreement with the recent measurement by the Galileo probe (Mahaffy, P.R., Donahue, T.M., Atreya, S.K., Owen, T.C., Niemann, H.B., 1998. Galileo probe measurements of D/H and 3He/4He in Jupiters atmosphere. Space Science Rev. 84 251–263); the D/H values on Uranus and Neptune are significantly higher, as expected from current models of planetary formation. 相似文献
3.
Observations of circumstellar dust clouds of Wolf-Rayet stars made with the Short Wavelength Spectrometer on ISO reveal a
subtle variety of spectral energy distributions not evident from ground-based observations. The modelling of these using the
radiative transfer code "Dusty" by Ivezić, Nenkova & Elitzur is reported. The results are used to examine the contributions
by different possible grain types to the emission and of circumstellar and interstellar components to the reddening.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
4.
J. Cernicharo 《Astrophysics and Space Science》1997,255(1-2):303-313
I present in this review the recent results obtained with ISO concerning gas phase molecules in evolved stars. The near, medium
and far-infrared spectrum of C-rich and O-rich stars can provide a very important information on the molecular content of
these objects. Detailed models for the envelopes of AGB stars are also presented. I also report the detection of triatomic
carbon in the far-infrared and I analyze the contribution of the ro-vibrational lines of the low energy bending modes of polyatomic
molecules in the far-infrared spectrum of C-rich evolved stars.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
5.
A. Salama P. Barr J. Clavel R. N. Jenkins K. Leech M.F. Kessler T. Lim L. Metcalfe B. Schulz A. Evans S. P. S. Eyres 《Astrophysics and Space Science》1997,255(1-2):227-235
We describe the ISO programme to observe classical novae. The programme includes observations of novae during and shortly
after eruption, and old novae. ISO observations of far infrared fine structure lines are providing us with information about
physical conditions in nova ejecta which complement and extend knowledge obtained from ground-based observations. Surprisingly,
we are getting little information about dust in nova systems, despite the fact that many novae are prolific dust-producers.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
6.
S.P.S. Eyres A. Evans A. Salama P. Barr J. Clavel N. Jenkins K. Leech M. Kessler T. Lim L. Metcalfe B. Schulz 《Astrophysics and Space Science》1997,255(1-2):361-366
A number of symbiotic stars have been observed with ISO. In addition to a number of emission lines, SWS observations of the
symbiotic novae RR Tel and V1016 Cyg reveal prominent, broad 10 & 18 μm silicate dust features. The 10 μm features are similar
to the crystalline silicate profiles seen in classical novae. There is some evidence that the silicate brightness in V1016
Cyg varies with Mira-component phase. However, the silicate feature in RR Tel also showed some variation even though observations
were made at very similar Mira-component phases. PHT observations of S-type symbiotic stars show the IR emission to be dominated
by the red-giant component. However, an excess in the PHT-P filters from 10 to 15 μm is evident in all the stars, and there
may be a broad 3.2 μm absorption feature or a broad 3.8 μm emission feature. At this time we have no adequate physical explanations
for any of these features.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
7.
概述了IRAS升空以来在AGB星研究方面的进展和发现的问题,比较详细地报告了60cm空间红外望远镜ISO携带的探测器及其性能,以及它的成像和光谱观测对研究AGB星的演化的影响,尤其是对AGB星星周包层的化学环境的研究的重要作用。 相似文献
8.
ISO-SWS spectra of two Mira variables (R Cas and T Dra), taken at two different pulsational phases, are presented. We describe
the reduction of the data and the encountered problems. The dust features observed by ISO at different phases and with the
Low Resolution Spectrometer of IRAS are compared. We briefly discuss the results in terms of current models for the circumstellar
dust shells of AGB variables.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
9.
We are obtaining low- (SWS01) and medium-resolution (SWS06) spectra of PPNe to investigate spectral features arising in these
transitional objects. Three sources with the 21 μm feature have been confirmed, one new source found, and evidence of some
substructure seen.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
10.
M.A. BarucciE. Dotto J.R. BrucatoT.G. Müller P. MorrisA. Doressoundiram M. Fulchignoni M.C. De SanctisT. Owen J. CrovisierA. Le Bras L. ColangeliV. Mennella 《Icarus》2002,156(1):202-210
Observations of emissivity features of 10 Hygiea have been made for the first time in the relatively unexplored thermal-infrared wavelength region with the ISO (Infrared Space Observatory) satellite. Spectrophotomer (PHT-S) and short wavelength spectrometer (SWS) spectra of 10 Hygiea, obtained at 5.8-11.6 and 7-45 μm, respectively, are presented. In order to remove the thermal emission continuum, an advanced thermo-physical model has been applied to the observational data. To better interpret the spectral features above the thermal emission continuum, we compared the ISO observations with laboratory spectra available in the literature. Several laboratory experiments on minerals and meteorites have been performed to complete the analysis and to study the spectral behavior at various grain sizes. A possible spectral similarity with CO carbonaceous chondrites at small grain size is demonstrated. 相似文献
11.
P.-O. Lagage 《Astrophysics and Space Science》1997,255(1-2):221-225
ISOCAM observations of Cassiopeia A (Cas A), the youngest supernova remnant known in our galaxy, are discussed. We show how
these observations are of interest for the so-called Cas A Neon problem and how these observations have renewed the interest
in supernovae as dust factories.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
12.
We exclude hydrogen-burning stars, of any mass above the hydrogen-burning limit and any metallicity, as significant contributors to the massive haloes deduced from rotation curves to dominate the outer parts of spiral galaxies. We present and analyse images of four nearly edge-on bulgeless spiral galaxies (UGC 711, NGC 2915, UGC 12426, UGC 1459) obtained with ISOCAM (The CAMera instrument on board the Infrared Space Observatory ) at 14.5 and 6.75 μm. Our sensitivity limit for detection of any diffuse infrared emission associated with the dark haloes in these galaxies is a few tens of μJy per 6 × 6 arcsec2 pixel, with this limit currently set by remaining difficulties in modelling the non-linear behaviour of the detectors. All four galaxies show zero detected signal from extended non-disc emission, consistent with zero halo-like luminosity density distribution. The 95 per cent upper limit on any emission, for NGC 2915 in particular, allows us to exclude very low mass main-sequence stars ( M > 0.08 M⊙) and young brown dwarfs (≲1 Gyr) as significant contributors to dark matter in galactic haloes. Combining our results with those of the Galactic microlensing surveys, which exclude objects with M < 0.01 M⊙, excludes almost the entire possible mass range of compact baryonic objects from contributing to Galactic dark matter. 相似文献
13.
The imager of the infrared satellite ISO will allow spectral imaging under very low flux conditions in the two to-eighteen-microns range, close to the fundamental limit of the zodiacal background photon noise. To optimize the performance of the imager, we must use an internal calibration device, mainly to track changes in the responsivity of the pixels of the detectors arrays, the limit of detection greatly depending upon the quality of the flat field corrections in certain cases.The first section introduces ISO and its infrared imager and emphasizes the necessity of in-flight calibration. The following chapter presents the specifications for the internal calibration device. The chosen design for the flight model which consists of an infrared emitter and two integrating spheres, is presented in the third chapter. The last part describes the cryogenic bench dedicated to relative photometric tests, the absolute calibration is made in the camera. Endly we present the results obtained with this facility and final tests to achieve the qualification of the device. 相似文献
14.
Erick T. Young 《Experimental Astronomy》2000,10(2-3):415-418
The Infrared Space Observatory successfullycarried out a wide range of astronomical observations in thewavelength range 2.4 m to nearly 200 m. To coverthis extremely broad range, a variety of detector technologies wereused by the instruments teams. As such ISO also proved to bean important test bed for the operation of these detectors ina low-background space environment. Over the two year mission,all the detector types have proven to be quite stable, withonly the Si:As IBC showing any long term degradation.Significant effort has been expended to cope with thebehaviour of the detectors under the space conditions bothoperationally and in ground processing. The main undesirableeffect can be classified as either transient responseanomalies or radiation effects. Overall sensitivity of theISO detectors was generally worse than predicted fromground-based measurements due to combinations of these twoclasses of phenomena. Splinter meetings were held to exchangespecific strategies for dealing with glitches, radiation curing,and transient effects. Plans for future actions were initiated. 相似文献
15.
Chris Pearson 《Monthly notices of the Royal Astronomical Society》2005,358(4):1417-1422
Galaxy source counts that simultaneously fit the deep mid-infrared surveys at 24 microns and 15 microns made by the Spitzer Space Telescope and the Infrared Space Observatory ( ISO ), respectively, are presented for two phenomenological models. The models are based on starburst and luminous infrared galaxy dominated populations. Both models produce excellent fits to the counts in both wavebands and provide an explanation for the high-redshift population seen in the longer Spitzer 24-micron band supporting the hypothesis that they are luminous–ultraluminous infrared galaxies at z = 2–3 , being the mid-infrared counterparts to the submillimetre galaxy population. The source counts are characterized by strong evolution to redshift unity, followed by less drastic evolution to higher redshift. The number–redshift distributions in both wavebands are well explained by the effect of the many mid-infrared features passing through the observation windows. The sharp upturn at around a millijansky in the 15-μm counts in particular depends critically on the distribution of mid-infrared features around 12 μm, in the assumed spectral energy distribution. 相似文献
16.
E. Oliva S. Drapatz D. Lutz E. Sturm A.F.M. Moorwood 《Astrophysics and Space Science》1997,255(1-2):211-219
ISO spectra of the supernova remnant RCW103 are presented. This object is the prototype of a SNR shock heavily interacting
with dense ISM (probably a molecular cloud). The spectra are dominated by prominent lines and show very little continuum at
λ < 40 μm suggesting that the 12 and 25 μm IRAS emission from these types of remnant could be dominated by lines rather than
continuum emission from warm dust heated by the shock as generally believed. The ISO data provide for the first time a simple
and reliable estimate of the gas phase abundances of Si and Fe which are found to be close to solar relative to non refractory
species such as Ne, S and Ar. This indicates that the shock is very effective in destroying the ISM dust and may therefore
explain the absence of warm dust behind the shock. Like the optical Nickel lines, [NiII]6.63 μm yields Ni/Fe abundances a
factor ≥ 10 above solar which we conclude results from a large underestimation of the computed Ni+ collision strengths.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
17.
S. Kimeswenger F. Kerber & R. Weinberger 《Monthly notices of the Royal Astronomical Society》1998,296(3):614-618
We present ISO observations of A58 and A78. Both objects are suspected to have undergone late He flashes ('born-again' nebulae). With ISOCAM we have been able to obtain data of much higher spatial resolution over the wavelength range 4.5–18 μm than has been possible in the past. In order to extract full information from our data we have developed a method to eliminate residual variations in the dark field. The results for A58 and A78 are compared with literature data and with A30 – the most prominent 'born-again' planetary nebula (PN). 相似文献
18.
We report on SWS and LWS observations of the circumstellar disks of young stars of a few solar masses. The ISO spectra of
these objects present a diversity of emission features of carbon-rich and oxygen-rich grains. The similarity of the forsterite
spectra observed for Comet Hale-Bopp and the Haebe star HD100546 is particularly striking and provides a new argument that
huge comet swarms are formed in the disks surrounding young stars. While the data suggest that the formation of crystalline
silicates in the dust disks essentially occurs when a Haebe star has already reached the main sequence, no clear correlation
with stellar age only is apparent.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
19.
V. Formisano T. Encrenaz M. Giuranna H. Hirsh N. Ignatiev E. Lellouch V. Moroz G. Piccioni B. Saggin 《Planetary and Space Science》2005,53(10):1043-1052
The evaluation of the planetary Fourier spectrometer performance at Mars is presented by comparing an average spectrum with the ISO spectrum published by Lellouch et al. [2000. Planet. Space Sci. 48, 1393.]. First, the average conditions of Mars atmosphere are compared, then the mixing ratios of the major gases are evaluated. Major and minor bands of CO2 are compared, from the point of view of features characteristics and bands depth. The spectral resolution is also compared using several solar lines. The result indicates that PFS radiance is valid to better than 1% in the wavenumber range 1800-4200 cm−1 for the average spectrum considered (1680 measurements). The PFS monochromatic transfer function generates an overshooting on the left-hand side of strong narrow lines (solar or atmospheric). The spectral resolution of PFS is of the order of 1.3 cm−1 or better. A large number of narrow features to be identified are discovered. 相似文献
20.
Neptune was observed by the Infrared Space Observatory (ISO) Long-Wavelength Spectrometer (LWS) between 46 and 185 μm. At wavelengths between 50 and 110 μm the accuracy of these measurements is ?0.3 K. Observations of this planet made by the ISO Short-Wavelength Spectrometer between 28 and 44 μm were combined with the LWS data to determine a disk-averaged temperature profile and derive several physical quantities. The combined spectra are matched best by a He/(H2+He) mass ratio of 26.4+2.6−3.5%, reflecting a He molar fraction of 14.9+1.7−2.2%, assuming the molar fraction of CH4 to be 2% in the troposphere. This He abundance is consistent with one derived from analysis of joint Voyager-2 IRIS and radio occultation experiment data, a technique whose accuracy has recently been called into question. For a disk average, the para-H2 fraction is found to be no more than ∼1.5% different from its equilibrium value, and the N2 mixing ratio is probably less than 0.7%. The composite spectrum is best fit by invoking a CH4 ice condensate cloud. Using a Mie approximation to particle scattering and absorption, best-fit particle sizes lie between 15 and 40 μm. The composite spectra are relatively insensitive to the vertical distribution of the cloud, but the particle scale height must be greater than 5% of the gas scale height. The best models are consistent with an effective temperature for Neptune that is 59.5±0.6 K, a value slightly lower than derived by the Voyager IRIS experiment—possibly Neptune's mid- and far-infrared emission has changed during the seven years that lie between its encounter with Voyager 2 and the first spectra taken of this planet with ISO. The model spectra are also ostensibly lower than ground-based observations in the spectral range of 17-24 μm, but this discrepancy can be relieved by perturbing the temperature of the lower stratosphere where the LWS spectrum is not particularly sensitive, combined with the uncertainty in the absolute calibration of the ground-based measurements. 相似文献