Search Publications
Minimal Aerosol Loading and Global Increases in Atmospheric Ozone during the 1996-1997 Martian Northern Spring Season
Wolff, Michael J.; Clancy, R. Todd; James, Philip B.
We employed the Hubble Space Telescope (HST) Faint Object Spectrograph (FOS) to observe middle ultraviolet (220-330 nm) spectral scans of Mars for two periods during the 1996-1997 northern spring season. Analysis of these data yields quantitative measurements of atmospheric column opacities for aerosols and ozone over a wide range of latitudes (40…
Solar Origin and Interplanetary Evolution of Stream Interfaces
Forsyth, R. J.; Marsch, E.
In a Corotating Interaction Region (CIR) the stream interface is identified as a relatively sharp density drop, temperature rise, and flow shear in the solar wind, and is now generally believed to mark the boundary between solar wind which was originally slow when it left the Sun and solar wind which was originally fast. This paper summarises some…
ISOCAM spectro-imaging of the H_2 rotational lines hfill in the supernova remnant IC 443
Boulanger, F.; van Dishoeck, E. F.; Wright, C. M. +3 more
We report spectro-imaging observations of the bright western ridge of the supernova remnant
Seasonal Change on Titan Observed with the Hubble Space Telescope WFPC-2
Lorenz, Ralph D.; Lemmon, Mark T.; Smith, Peter H. +1 more
Recent observations with the Wide-Field Planetary Camera (WFPC-2) on the Hubble Space Telescope (HST) show an unexpectedly rapid change in the atmospheric albedo contrast between the north and south hemispheres. In 1994 at blue wavelengths, the north was around 15% brighter than the south, and was expected to fall to about 12% in 1997, but has dro…
Infrared Space Observatory Observations toward the Reflection Nebula NGC 7023: A Nonequilibrium Ortho-to-Para-H2 Ratio
Rodríguez-Fernández, N. J.; Martín-Pintado, J.; Fuente, A. +3 more
We have observed the S(0), S(1), S(2), S(3), S(4), and S(5) rotational lines of molecular hydrogen (H2) toward the peak of the photodissociation region (PDR) associated with the reflection nebula NGC 7023. The observed H2 line ratios show that they arise in warm gas with kinetic temperatures ~300-700 K. However, the data cann…
Observation of a 3d Magnetic Null Point in the Solar Corona
Filippov, Boris
A saddle-like structure is clearly discerned in SOHO EIT images in the Fe wavebands in the active region NOAA 8113, from 6 to 10 December 1997, when the active region reached the solar limb. It appears after the emergence of a small patch of parasitic polarity near the footpoints of the loops forming the outer boundary of an arcade. There is a 3D …
Infrared spectral observations of comet 103P/Hartley 2 by ISOPHOT
Fulle, M.; Brucato, J. R.; Mennella, V. +7 more
Spectral observations in the 2.5-12 mu m range of comet 103P/Hartley 2 were performed on 1 Jan. 1998 by the ISOPHOT instrument, on board the Infrared Space Observatory. The obtained spectrum evidences intense bands at 2.66 and 4.26 mu m, attributable to H_2O and CO_2, respectively. The derived molecular production rates are Q(H_2O) = (3.1 +/- 0.2)…
Evolution of the Light Echo of SN 1991T
Panagia, N.; Della Valle, M.; Sparks, W. B. +4 more
Schmidt et al. presented strong evidence (photometry and spectroscopy) that the late time optical emission of SN 1991T in the Virgo spiral NGC 4527 is caused by a light echo. Here, we present photometry with the Wide Field and Planetary Camera 2 and high-resolution imaging polarimetry and photometry with the Faint Object Camera on board the Hubble…
On the sunspot transition region
Wilhelm, K.; Fredvik, T.; Kjeldseth-Moe, O. +2 more
The EUV line emission and relative line-of-sight velocity in the transition region between the chromosphere and corona of 36 sunspot regions are investigated, based on observations with the Coronal Diagnostic Spectrometer - CDS and the Solar Ultraviolet Measurements of Emitted Radiation - SUMER on the Solar and Heliospheric Observatory - SOHO. The…
Solar Wind Models from the Sun to 1 AU: Constraints by in Situ and Remote Sensing Measurements
Marsch, E.
There are three major types of solar wind: The steady fast wind originating on open magnetic field lines in coronal holes, the unsteady slow wind coming probably from the temporarily open streamer belt and the transient wind in the form of large coronal mass ejections. The majority of the models is concerned with the fast wind, which is, at least …