Astronomy and Astrophysics – Astronomy
Scientific paper
May 1998
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1998apj...499..482c&link_type=abstract
Astrophysical Journal v.499, p.482
Astronomy and Astrophysics
Astronomy
17
Interplanetary Medium
Scientific paper
We present high-resolution spectra of the emission-line profile of inflowing interplanetary hydrogen atoms along lines of sight with the Earth orbital motion upwind (into the flow), downwind, and across the flow to Doppler-shift the line from the geocoronal emission. The line-center positions, in comparison with hot-model profiles, confirm that the inflow speed of H atoms far from the Sun (~50 AU) is in the range 18-21 km s-1, which implies a decrease in the velocity distribution of 5-8 km s-1 for hydrogen within the solar system, relative to the He flow and to the local interstellar medium. Best-fit values are derived for the speed and effective solar gravity along the three lines of sight by comparison with model profiles convolved with the instrument line-spread function. For the assumed inflow direction, the cross-flow line profile requires that the mu -value be slightly less than unity near solar minimum, and a technique is presented for determining the exact inflow direction and mu -value independently of the other parameters. The line widths indicate a broadening along the flow direction in addition to the dynamical effects near the Sun expected from two different hot models, whereas the cross-flow line width is similar to the hot-model profiles. The altered velocity distribution in the inflow direction appears likely to be related to the crossing of the interstellar/interplanetary medium interface structure, although questions remain about the cumulative effects of changing solar activity on the timescale of the H atom flow through the solar system.
Bertaux Jean Loup
Clarke John T.
Fahr Hans
Lallement Rosine
Quémerais Eric
No associations
LandOfFree
HST/GHRS Observations of the Velocity Structure of Interplanetary Hydrogen does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with HST/GHRS Observations of the Velocity Structure of Interplanetary Hydrogen, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and HST/GHRS Observations of the Velocity Structure of Interplanetary Hydrogen will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1367742