scholarly journals SIRTF: A Unique Opportunity for Probing the Zodiacal Cloud

1996 ◽  
Vol 150 ◽  
pp. 159-162
Author(s):  
Sumita Jayaraman ◽  
Stanley F. Dermott ◽  
Michael Werner
Keyword(s):  
Thermal Emission ◽  
Dust Cloud ◽  
Thermal Characteristics ◽  
Dust Particles ◽  
Infrared Telescope ◽  
The Earth ◽  
Telescope Facility ◽  
Asteroidal Dust ◽  
Infrared Telescope Facility ◽  
Dust Ring

AbstractThe Space Infrared Telescope Facility (SIRTF) is planned for launch by NASA in 2001 in a heliocentric orbit at 1.01 AU The spacecraft will drift away from the Earth slowly, reaching a distance of 0.3 AU behind the Earth at the end of its 2.5 year mission. This implies that SIRTF will spiral through the Earth's resonant dust ring (Wright et al., 1995) and, in particular, that it will traverse the dust cloud in the ring that trails the Earth in its orbit. We have used a dynamical model of the ring (Dermott et al., 1994) followed by simulation of the SIRTF orbit to predict the variations in the zodiacal thermal emission due to the trailing dust cloud as seen by SIRTF. Because the dust ring is inclined to the ecliptic, the latitude of peak flux of the trailing cloud will have yearly oscillations about the ecliptic. The amplitude of the oscillations will increase as SIRTF approaches the cloud, reaching a maximum of 20 during the mission. The magnitude of the flux variations can be as high as 4 – 5% or 2–3 MJy/Sr, SIRTF's measurements of these effects will allow us to model the number density and thermal characteristics of asteroidal dust particles near the Earth.

Space Infrared Telescope Facility (SIRTF) Science Instruments

1988 ◽  
Author(s):  
R Ramos ◽  
S. M. Hing ◽  
C. A. Leidich ◽  
G. Fazio ◽  
J R. Houck ◽  
...  
Keyword(s):  
Infrared Telescope ◽  
Telescope Facility ◽  
Infrared Telescope Facility

Shuttle Infrared Telescope Facility Pointing And Control System

1981 ◽  
Author(s):  
Kenneth R. Lorell ◽  
William F. Barrows ◽  
Yutaka T. Matsumoto
Keyword(s):  
Control System ◽  
Infrared Telescope ◽  
Telescope Facility ◽  
And Control ◽  
Infrared Telescope Facility

Here Today, Gone Tomorrow

2020 ◽  
pp. 221-241
Author(s):  
David A. Weintraub
Keyword(s):  
Martian Atmosphere ◽  
Popular Press ◽  
Astronomical Society ◽  
Infrared Telescope ◽  
American Astronomical Society ◽  
Telescope Facility ◽  
Infrared Telescope Facility

This chapter talks about Mike Mumma and his team, which chronologically is the first group to publicly stake a claim to having discovered methane in the atmosphere of Mars in 2003. It explores the May 2003 abstract that served as a placeholder for a presentation Mumma would give at an American Astronomical Society Division of Planetary Sciences meeting. It also cites Mumma's report on his team's attempt to detect methane on Mars using three different telescopes: NASA's 3-meter Infrared Telescope Facility (IRTF), the 8-meter Gemini South telescope in Chile, and the 10-meter Keck-2 telescope. The chapter provides the details of Mumma's measurements that show that the level of methane in the Martian atmosphere was about 10 parts per billion, averaged across the full atmosphere of Mars. It points out how all the early 2004 announcements about methane on Mars received immediate attention in the popular press.

scholarly journals Estimating the Asteroidal Component of the Zodiacal Cloud using the Earth's Resonant Ring

1996 ◽  
Vol 150 ◽  
pp. 155-158 ◽  
Author(s):  
Sumita Jayaraman ◽  
Stanley F. Dermott
Keyword(s):  
Surface Area ◽  
Frequency Distribution ◽  
Size Range ◽  
Dust Cloud ◽  
Dust Particles ◽  
Direct Function ◽  
Size Frequency Distribution ◽  
Limited Size ◽  
Zodiacal Cloud ◽  
Asteroidal Dust

AbstractThe Earth's resonant ring is populated primarily by asteroidal dust particles because cometary particles have higher Poynting-Robertson drag rates and the Earth's resonances are not strong enough to trap them (Gomes, 1995). It has been shown that asteroidal particles in a limited size range from 5 — 30μm are responsible for the observed trailing/leading flux asymmetry caused by the trailing dust cloud embedded in the ring (Jayaraman and Dermott 1995). The magnitude of the flux asymmetry is a direct function of the area of dust in the ring, which in turn depends upon the number of asteroidal particles in the zodiacal cloud. Using a dynamical model of the ring and the background zodiacal cloud and estimating the surface area of dust needed in the ring to match the observed flux asymmetry in the 25 micron COBE waveband, we have calculated the fraction of asteroidal dust in the zodiacal cloud as a function of p, the slope of the size-frequency distribution of particles.

scholarly journals 12-μM Observations at the 1991 Eclipse

1994 ◽  
Vol 154 ◽  
pp. 151-160
Author(s):  
D. E. Jennings ◽  
D. Deming ◽  
G. Mccabe ◽  
R. Noyes ◽  
G. Wiedemann ◽  
...  
Keyword(s):  
Line Emission ◽  
Emission Feature ◽  
Hydrostatic Equilibrium ◽  
Infrared Telescope ◽  
Model Predictions ◽  
Theoretical Predictions ◽  
Telescope Facility ◽  
Density Inhomogeneities ◽  
Infrared Telescope Facility ◽  
The Continuum

The 11 July 1991 total solar eclipse over Mauna Kea was a unique opportunity to study the limb profile of the 12.32 μm MgI emission line. Our observations used the NASA 3-meter Infrared Telescope Facility,1 and a new Goddard large cryogenic grating spectrometer. Spectra of the line were taken in the slitless mode at second contact. The results show that the emission peaks within ~ 300 km of the 12-μm continuum limb. This agrees with recent theoretical predictions for this line as a NLTE upper photospheric emission feature. However, the increase in optical depth for this extreme limb-viewing situation means that most of the observed emission arises from above Tmin, and we find that this emission is extended to altitudes well in excess of the model predictions. The line emission can be traced to altitudes as high as 2000 km above the 12-μm continuum limb, whereas theory predicts it to remain observable no higher than 500 km above the continuum limb. The substantial limb-extension observed in this line is qualitatively consistent with limb-extensions seen by other observers in the far-IR continuum, and may be indicative of departures from gravitational hydrostatic equilibrium in the upper solar atmosphere, and/or may result from temperature and density inhomogeneities. The extended altitude of formation of this line enhances its value as a Zeeman probe of magnetic fields.

scholarly journals SpeX Spectroscopy of Mercury: 0.8 – 5.2 µm

2005 ◽  
Vol 13 ◽  
pp. 53-55
Author(s):  
Ann L. Sprague ◽  
Johan Warell ◽  
Joshua Emery ◽  
Angela Long ◽  
John Rayner ◽  
...  
Keyword(s):  
Thermal Flux ◽  
Absorption Feature ◽  
Infrared Telescope ◽  
Surface Temperatures ◽  
Telescope Facility ◽  
Infrared Telescope Facility

AbstractSpectra of Mercury were obtained at the Infrared Telescope Facility on Mauna Kea, HI using SpeX. There is no indication of any absorption feature associated with FeO in Mercury’s regolith. There is a 5μ m excess in thermal flux similar to that observed from the Kuiper Airborne Observatory (KAO) using HIFOGS. Spectra from varying locations do exhibit different slopes and flux indicating different surface temperatures at different locations.

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