Polarimetry in the Ultraviolet to Find Features in INterStellar dust
PUFFINS with a 25 cm telescope feeding a spectropolarimeter will significantly advance our understanding of the characteristics and dynamics of
interstellar dust grains and their interaction with the environment, and probe the magnetic fields
Animation: NASA. Specks of space dust drift past in this illustration
70
Stars observed, spread across the sky
1800–3200 Å
Ultraviolet bandpass
0.02%
Polarimetric accuracy
25 cm
Primary mirror
9 months
Science survey
The mission
How grains form and evolve, as well as their composition and structure,
are long-standing problems of astrophysics.
The interstellar medium (ISM) is a dynamic, multi-phased environment consisting
of dust, gas, and cosmic rays permeated by radiation and magnetic fields. Stars
are formed from the ISM and interact with and replenish it through stellar
radiation, winds, and mass loss. The dust in the ISM provides a source of
extinction, shielding complex molecules from dissociation and a cooling
mechanism for molecular clouds. While of critical importance in the evolution of
the universe, the dust composition, evolution, and dynamics are still not fully
understood, especially in regard to the smallest grains. Ultraviolet (UV)
polarimetry provides a unique tool to probe the characteristics, dynamics, and
evolution of small grain populations through its sensitivity to grain
mineralogy, size, and environmental parameters.
Interstellar polarization is due to the elongated dust grains aligned with a
magnetic field. Radiative torques from the differential scattering of incident
radiation’s right- and left-hand circular components spin grains up and align the
paramagnetic silicate grains (blue). Carbon solids (orange) are diamagnetic and are
not expected to align under most circumstances. The polarization from the small
grains will be observed with PUFFINS. The observations will investigate the enhanced
UV polarization below 3200 Å and discover the origin of the polarization in the
2175 Å extinction feature. Two measurements made by WUPPE 30 years ago are shown.
Since WUPPE, no UV polarimetry mission has flown, leaving the question of
interstellar UV polarization largely unsolved.
Credit: PUFFINS team.
How do star-forming structures arise from and interact with the diffuse
interstellar medium?
Science objective 1
Super-Serkowski polarization (SuSeP) in the UV
Investigate the nature and extent of small grain alignment by measuring
SuSeP at wavelengths below 3200 Å.
Science objective 2
The 2175 Å extinction feature
Determine the origin and prevalence of the polarization in the
2175 Å feature.
Science objective 3
Survey of ISM UV polarization
Survey ISM UV polarization along a substantial number of lines of sight
with varying extinction, metallicity, depletion levels, and ISM and
radiation field characteristics.
Latest
Mission updates
Critical design review
The detailed design is reviewed before the team proceeds to build
flight hardware.
Systems requirements review
The mission's requirements and concept of operations are reviewed
end to end at SRR.
Selected for NASA’s Astrophysics Pioneers program
PUFFINS was selected by NASA’s Astrophysics Pioneers program, which
funds compelling astrophysics investigations on small platforms and
gives early- and mid-career researchers the chance to lead a mission.
Concept development supported by UASI
Early design work was supported by funding from the University of
Arizona Space Institute.
Get in touch
Work with us
We welcome collaboration on target selection, ground-based supporting
spectropolarimetry, and grain-alignment modelling. Students interested in
working on UV instrumentation can get in touch directly.
