NASA Scientific and Technical Aerospace Reports

ejected subsequently by the planet as it migrates further inward. This allows the planet to migrate a substantial fraction of its
initial semimajor axis by ejecting planetesimals.
Author
Extrasolar Planets; Protoplanets; Planetary Orbits; Orbital Mechanics
20040074152 Naval Observatory, Washington, DC, USA, National Radio Astronomy Observatory, Socorro, NM, USA
Ground-State SiO Maser Emission Toward Evolved Stars
Boboltz, D. A.; Claussen, M. J.; Feb. 20, 2004; 18 pp.; In English; Original contains color illustrations
Report No.(s): AD-A422690; No Copyright; Avail: CASI; A03, Hardcopy
We have made the first unambiguous detection of vibrational ground-state maser emission from 28SiO toward six evolved
stars. Using the Very Large Array, we simultaneously observed the v = 0,J = 1-0, 43.4-GHz, groundstate and the v = 1,J = 1-0,
43.1-GHz, first excited-state transitions of 28SiO toward the oxygen-rich evolved stars IRC+10011, o Ceti, W Hya, RX Boo,
NML Cyg, and R Cas and the S-type star chi Cyg. We detected at least one v=0SiOmaser feature from six of the seven
stars observed, with peak maser brightness temperatures ranging from 10000 K to 108800 K. In fact, four of the seven v =
0 spectra show multiple maser peaks, a phenomenon which has not been previously observed. Ground-state thermal emission
was detected for one of the stars, RX Boo, with a peak brightness temperature of 200 K. Comparing the v=0andthev=
1 transitions, we find that the ground-state masers are much weaker with spectral characteristics different from those of the
first excited-state masers. For four of the seven stars the velocity dispersion is smaller for the v=0emission than for the v
= 1 emission, for one star the dispersions are roughly equivalent, and for two stars (one of which is RX Boo) the velocity
spread of the v=0emission is larger. In most cases, the peak flux density in the v = 0 emission spectrum does not coincide
with the v=1maser peak. Although the angular resolution of these VLA observations were insufficient to completely resolve
the spatial structure of the SiO emission, the SiO spot maps produced from the interferometric image cubes suggest that the
v = 0 masers are more extended than their v=1counterparts.
DTIC
Ground State; Interferometry; Masers; Radio Astronomy
20040074164 Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA
Long-Term Stability of Planets in Binary Systems
Holman, Matthew J.; Wiegert, Paul A.; The Astronomical Journal; 1′999; Volume 117, pp. 621-628; In English
Contract(s)/Grant(s): NAG5-10365; No Copyright; Avail: Other Sources; Abstract Only
A simple question of celestial mechanics is investigated: in what regions of phase space near a binary system can planets
persist for long times? The planets are taken to be test particles moving in the field of an eccentric binary system. A range of
values of the binary eccentricity and mass ratio is studied, and both the case of planets orbiting close to one of the stars, and
that of planets outside the binary orbiting the systems center of mass, are examined. From the results, empirical expressions
are developed for both (1) the largest orbit around each of the stars and (2) the smallest orbit around the binary system as a
whole, in which test particles survive the length of the integration (10A4 binary periods). The empirical expressions
developed, which are roughly linear in both the mass ratio mu and the binary eccentricity e, are determined for the range
0.0=e=0.7-0.8 and 0.1=mu=0.9 in both regions and can be used to guide searches for planets in binary systems. After
considering the case of a single low-mass planet in binary systems, the stability of a mutually interacting system of planets
orbiting one star of a binary system is examined, though in less detail.
Author
Planets; Center of Mass; Eccentricity; Celestial Mechanics; Systems Stability
20040074165 Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA
On the Origin of Chaos in the Asteroid Belt
Murray, N.; Holman, M.; Potter, M.; The Astronomical Journal; 1998; Volume 116, pp. 2583-2589; In English
Contract(s)/Grant(s): NAG5-10365; No Copyright; Avail: Other Sources; Abstract Only
We consider the effect of gravitational perturbations from Jupiter on the dynamics of asteroids, when Jupiter is itself
perturbed by Saturn. The presence of Saturn introduces a number of additional frequencies into Jupiters orbit. These
frequencies in turn produce chaos in narrow regions on either side of the chaotic zones associated with the mean motion
resonances between the asteroids and Jupiter. The resonant arguments of these three-body resonances contain the longitudes
of Jupiter and the asteroid together with either the secular frequency 9-6, or the longitude of Saturn. Resonances involving
the longitude of Saturn are analogs of the Laplace resonance in the Jovian satellite system. We show that many three-body
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