scholarly journals ISO: Asteroid Results and Thermophysical Modeling

2005 ◽  
Vol 13 ◽  
pp. 749-751
Author(s):  
Thomas G. Müller
Keyword(s):  
Thermal Inertia ◽  
Far Infrared ◽  
Rotational Behaviour ◽  
Sources Of Information ◽  
Infrared Space Observatory ◽  
Thermophysical Model ◽  
Infrared Surveys ◽  
Thermophysical Modeling ◽  
Ir Photometry

AbstractThrough a recently developed thermophysical model, observations from the Infrared Space Observatory (ISO) were combined with visual photometry, lightcurves, close-up observations and direct measurement. In this way, many applications were possible, ranging from simple diameter and albedo determination of serendipitously seen asteroids to sophisticated studies of mineralogic aspects and regolith properties, like emissivity, roughness or thermal inertia for well-known asteroids. The possibility to combine all sources of information in one single model lead also to a better understanding of thermophysical effects, like beaming or the before/after opposition effect. Thus, the mineralogic signatures can be recognized easier and asteroid data from infrared surveys and individual IR photometry can be interpreted more accurately, even in cases where shape or rotational behaviour are not known. Some well-studied asteroids are now even considered as excellent far-infrared calibrators.

The 3.1 μm absorption feature on asteroids (24) Themis and (65) Cybele is not due to surface water ice

2021 ◽  
Author(s):  
Laurence O'Rourke ◽  
Thomas G. Müller ◽  
Nicolas Biver ◽  
Dominique Bockelée-Morvan ◽  
Sunao Hasegawa ◽  
...  
Keyword(s):  
Surface Water ◽  
Line Emission ◽  
Thermal Inertia ◽  
Infrared Camera ◽  
Far Infrared ◽  
Subsurface Water ◽  
Absorption Feature ◽  
Water Ice ◽  
V Band ◽  
Thermophysical Model

<p>Previous research on Asteroids (24) Themis and (65) Cybele have shown the presence of an absorption feature at 3.1 μm reported to be directly linked to surface water ice. We searched for water vapor escaping from these asteroids with the Herschel Space Observatory HIFI (Heterodyne Instrument for the Far Infrared) Instrument. While no H<sub>2</sub>O line emission was detected, we obtained sensitive 3σ water production rate upper limits of Q(H<sub>2</sub>O)< 4.1×10<sup>26</sup> molecules s<sup>−1</sup> for Themis and Q(H<sub>2</sub>O) <7.6 × 10<sup>26</sup> molecules s<sup>−1</sup> for the case of Cybele. Using a thermophysical model, we merged data from the Subaru/Cooled Mid-Infrared Camera and Spectrometer and the Herschel SPIRE (Spectral and Photometric Imaging Receiver) instrument with the contents of a multi-observatory database and thus derived new radiometric properties for these two asteroids. For Themis, we obtained a thermal inertia G = 20 <sup>+25</sup><sub>-10</sub> J m<sup>−2</sup> s<sup>−1/2</sup> K<sup>−1</sup>, a diameter 192 <sup>+10</sup><sub>-7</sub> km, and a geometric V-band albedo p<sub>V</sub>=0.07±0.01. For Cybele, we found a thermal inertia G = 25<sup>+28</sup><sub>-19</sub> J m<sup>−2</sup> s<sup>−1/2</sup> K<sup>−1</sup>, a diameter 282±9 km, and an albedo pV=0.042±0.005. Using all inputs, we estimated that water ice intimately mixed with the asteroids’ dark surface material would cover <0.0017% (for Themis) and <0.0033% (for Cybele) of their surfaces, while an areal mixture with very clean ice (Bond albedo 0.8 for Themis and 0.7 for Cybele) would cover <2.2% (for Themis) and <1.5% (for Cybele) of their surfaces. Based on these very low percentage coverage values, it is clear that while surface (and subsurface) water ice may exist in small localized amounts on both asteroids, it is not the reason for the observed 3.1 μm absorption feature.</p>

Low Water outgassing from (24) Themis and (65) Cybele – Implications on 3.1 µm water absorption spectra understanding

2020 ◽  
Author(s):  
Laurence O'Rourke ◽  
Thomas Müller ◽  
Nicolas Biver ◽  
Dominique Bockelée-Morvan ◽  
Sunao Hasegawa ◽  
...  
Keyword(s):  
Surface Water ◽  
Line Emission ◽  
Thermal Inertia ◽  
Far Infrared ◽  
Absorption Feature ◽  
Water Ice ◽  
V Band ◽  
Upper Limits ◽  
Thermophysical Model ◽  
Water Production Rate

<p>Asteroids (24) Themis and (65) Cybele have an absorption feature at 3.1 µm reported to be directly linked to surface water ice. We searched for water vapour escaping from these asteroids with the Herschel Space Observatory Heterodyne Instrument for the Far Infrared (HIFI). While no H<sub>2</sub>O line emission was detected, we obtain sensitive 3σ water production rate upper limits of Q(H<sub>2</sub>O) < 4.1 × 10<sup>26 </sup>mol. s<sup>−</sup><sup>1</sup> for Themis and Q(H<sub>2</sub>O) < 7.6 × 10<sup>26 </sup>mol. s<sup>−</sup><sup>1</sup> for Cybele. Using a Thermophysical Model (TPM), we merge data from Subaru/Comics and Herschel/SPIRE with the contents of a multi-observatory database to derive new radiometric properties for these two asteroids. For Themis, we find a thermal inertia Γ = 20<sup>+25</sup><sub>-10</sub> J m<sup>-2</sup> s<sup>-1/2</sup> K<sup>-1</sup>, a diameter 192 <sup>+10</sup><sub>-7</sub> km and a geometric V-band albedo p<sub>V </sub>= 0.07 ±0.01. For Cybele we obtain a thermal inertia Γ = 25 <sup>+28</sup><sub>-19</sub> J m<sup>-2</sup> s<sup>-1/2</sup> K<sup>-1</sup>, a diameter 282 ± 9 km, and an albedo p<sub>V </sub>= 0.042± 0.005. Using all inputs, we estimate that water ice intimately mixed with the asteroids’ dark surface material would cover < 0.0017% for Themis and < 0.0033% for Cybele of their surfaces, while an areal mixture with very clean ice (bond albedo 0.8 for Themis and 0.7 for Cybele) would cover < 2.2% for Themis and < 1.5% for Cybele, of their surfaces. While surface (& sub-surface) water ice may exist in small localized amounts on both asteroids, it is not the reason for the observed 3.1µm absorption feature.</p>

scholarly journals Determination of confusion noise for far-infrared measurements

2005 ◽  
Vol 430 (1) ◽  
pp. 343-353 ◽  
Author(s):  
Cs. Kiss ◽  
U. Klaas ◽  
D. Lemke
Keyword(s):  
Far Infrared ◽  
Infrared Measurements

scholarly journals Seyfert galaxies: a perspective with ISO-PHOT

1999 ◽  
Vol 193 ◽  
pp. 750-751
Author(s):  
Ana M. Pérez García ◽  
J.M. Rodríguez Espinosa
Keyword(s):  
Temperature Distribution ◽  
Far Infrared ◽  
Seyfert Galaxies ◽  
Inversion Method ◽  
Space Observatory ◽  
Infrared Space Observatory ◽  
Energy Distributions ◽  
Spectral Components ◽  
Ir Emission

We present mid and far-infrared energy distributions of the CfA Seyfert sample, obtained with the Infrared Space Observatory photometer (ISO-PHOT). To analyse the CfA Seyfert SEDS, we apply an inversion method: the Inverse Planckian Transform, assuming that the mid- and far-IR emission is thermal. We obtain the spectral temperature distribution of sources that reproduces the observed SEDS. We compare the parameters of the spectral components found showing that there are not differences between Seyfert 1 and Seyfert 2 as for their temperatures while the emission between 12 and 25 μm is anisotropic.

scholarly journals ALMA witnesses the assembly of first galaxies

2019 ◽  
Vol 15 (S352) ◽  
pp. 27-32
Author(s):  
Stefano Carniani
Keyword(s):  
Star Formation ◽  
Physical Properties ◽  
Rest Frame ◽  
Near Infrared ◽  
Far Infrared ◽  
Star Forming ◽  
Surrounding Environment ◽  
Infrared Surveys ◽  
Formation And Evolution ◽  
First Galaxies

AbstractCharacterising primeval galaxies entails the challenging goal of observing galaxies with modest star formation rates (SFR < 100 Mȯyr−1) and approaching the beginning of the reionisation epoch (z > 6). To date a large number of primeval galaxies have been identified thanks to deep near-infrared surveys. However, to further our understanding on the formation and evolution of such primeval objects, we must investigate their nature and physical properties through multi-band spectroscopic observations. Information on dust content, metallicity, interactions with the surrounding environment, and outflows can be obtained with ALMA observations of far-infrared (FIR) lines such as the [Cii] at 158 μm and [Oiii] at 88 μm. Here, we, thus, discuss the recent results unveiled by ALMA observations and present new [Cii] observations of BDF-3299, a star-forming galaxy at z = 7.1 showing a spatial and spectral offset between the rest-frame UV and the FIR lines emission.

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