Research
My current interests lie in the atmospheres of the giant planets, specifically
Uranus and Neptune. While it was originally thought that they were two more
gas giants similar to Jupiter and Saturn, we are now starting to realize that
this is not the case. We need to look more carefully at these two ice
giants to figure out what they're really like.
At the moment, I'm working with Dr. Nancy Chanover and Dr. David Voelz on a
project focusing on improving the quality of information we can obtain from
ground-based images of the giant planets. A variety of techniques can be used
for this purpose, such as adjustment of the Fourier transforms of the images.
One of the more recent procedures we're using is to stitch together various
good pieces from a series of images taken in rapid succession, with the goal
of producing one image that is better than any of the individual images.
As Uranus approaches its December 2007 equinox, we are treated to a unique
opportunity to observe an atmosphere that has become much more active since
Voyager's flyby near solstice, as well as a favorable viewing geometry in
which the lines of constant latitude as seen from Earth are straight and
parallel.
In September 2006, near-IR spectra of Uranus were taken using the SpeX
instrument (R roughly 1000-2000) at NASA's Infrared Telescope Facility
(IRTF). We use these data to constrain the vertical abundance profile of
methane, the most abundant component of the Uranian atmosphere following H2
and He. A spectral synthesis program developed at NASA/Goddard Space Flight
Center for the analysis of infrared spectroscopy was employed to determine the
properties of a model atmosphere that best reproduce the methane features
observed.
These spectra are being supplemented by high-resolution visible spectra taken
with the ARC echelle spectrograph (R = 37,500) on the 3.5-m telescope at
Apache Point Observatory in Sunspot, New Mexico, in October 2005 and August
2006. The new activity seen in Uranus' atmosphere near equinox, such as the
appearance of new cloud features indicates that the Uranian atmosphere
undergoes dramatic seasonal changes. There is a strong possibility of
changes in the methane profile that have occurred since previous observations
in the 1970s.
We are also taking advantage of the unique observing geometry
near Uranian equinox to examine any variations in the methane distribution
with latitude.
Publications
Monitoring the Mass Accretion Rate in Scorpius X-1 Using the Optical Johnson B Filter
McNamara, B. J., Norwood, J., Harrison, T. E., Holtzman, J., Dukes, R., & Barker, T.
2005, ApJ, 623, 1070
Meetings
October 2006: Division for Planetary Sciences meeting, Constraints On The Distribution Of Methane In Uranus' Atmosphere
J. Norwood, N. Chanover, & H. Hammel
Teaching
I have previously been a teaching assistant for Astronomy 105G. My lab webpage can be
found here.
I am pleased to thank NASA for a generous Earth and Space Sciences Fellowship (NESSF).
