TPF-I SWG Report - Exoplanet Exploration Program - NASA

G ENERAL A STROPHYSICS
3.2.5 Other Science Opportunities
• Our home planetary system: TPF-I/Darwin will easily measure the diameters, and properties of
dwarf planets (Kuiper Belt Objects), moons, asteroids, and comet nuclei. Low-resolution spectrophotometry
will constraint the natures of surfaces, atmospheres, and environments.
• Parallax and proper motions in the Galactic Plane: Establish a network of Galactic fiducial
distance markers using IR-bright stars.
• Resolve milli-arcsecond separation of multiple stars: Search for compact binaries formed
during the dynamical decay of non-hierarchical multiple star systems and the ejection of high
velocity stars in embedded young clusters.
• Are there intermediate black Holes (IMBHs) in the Galactic Center Is there a 1000–10,000
Solar mass black hole in the IRS13 cluster in the GC, or in other clusters in this region The
presence of IMBHs may explain how dynamical friction has enabled the migration of massive
stars into the immediate vicinity of SgrA*. TPF-I will measure the mass functions and measure
proper motions of cool stars and red-giants in the IRS 13 cluster, complementing measurements
with ELTs to determine the presence or absence of IMBHs.
• Image stellar micro-lensing events: (target of opportunity, TOO, program). Another unique
application for TPF-I will be resolving micro-lensing events detected in future infrared galactic
plane surveys. Currently, most microlensing surveys are executed in the visible wavelengths;
thus, they have been limited to fields out of the galactic plane (e.g.,the galactic Halo and the
Large Magellanic Cloud). However, infrared detection is necessary to observe inner bulge stars
or to investigate the massive astronomical compact halo object MACHO population in the central
galaxy. TPF-I/Darwin will have the resolution to resolve some of the lensing events allowing the
mass-distance ambiguity to be lifted in the gravitational lens model (Boden et al. 1988; Dalal and
Lane 2003) and to detect the lensing star directly in some cases (Nguyen et al. 2004).
• Excretions disk and exotic high luminosity objects in the Milky Way and the Local Group:
Eta-Carinae-like objects, LBVs, Be star excretion disks, and other objects.
• Micro-quasars: TPF-I/Darwin will probe excretion disks produced by Roche-Lobe overflow
and trace the inner portions of relativistic jets by means of IR synchrotron emission and ions
entrained in the jet sheath.
• SNe: TPF-I/Darwin will be able to image the formation and evolution of dust in supernova ejecta
and trace the structure of the circumstellar environment into which the blast is propagating. The
dust, molecules, atoms, and ions launched by the supernova progenitor are illuminated by both
the supernova flash and by the advancing shock front of the ejecta. Over a wide range of
conditions, the resulting emission from the circumstellar environment peaks in the IR.
• Dark Matter and dark energy: Darwin/TPF-I studies of gravitational lensing by galaxy
clusters, AGN, and ordinary galaxies may provide a unique tool for probing the nature of dark
matter. Measurements of background time-variable objects in gravitationally lensed systems will
enable accurate characterizations of differential time-delays along different ray paths, giving
clues about the geometry of the space-time in the lensing objects. These measurements, when
made with milli-arcsecond resolution, will provide unprecedented constraints on the structure of
dark matter haloes.
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