PUFFINS

Polarimetry in the Ultraviolet to Find Features in INterStellar dust

PUFFINS, a 25 cm telescope feeding a spectropolarimeter, will advance our understanding of the characteristics and dynamics of interstellar dust grains, how they interact with their environment, and probe 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
25 cm
Primary mirror
9 months
Science survey

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.

Three-panel figure. Left: radiative torques spinning up and aligning a dust grain with the magnetic field, and starlight from a background star becoming polarized as it passes through aligned silicate grains. Centre: the PUFFINS spacecraft. Right: measured polarization curves for HD 197770 and HD 30614 showing the polarized bump and the super-Serkowski rise, above extinction curves marking the 2175 angstrom bump.
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 other dedicated UV polarimetry mission has flown, leaving the question of interstellar UV polarization largely unsolved. Credit: PUFFINS team.

Read the science case

Science goal

How do star-forming structures arise from and interact with the diffuse interstellar medium?

Science objective 1

Super-Serkowski polarization 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.

Mission timeline

  • Concept development supported by the University of Arizona Space Institute

  • Selected for NASA’s Astrophysics Pioneers program

    The program funds compelling astrophysics investigations on small platforms and gives early- and mid-career researchers the chance to lead a mission.

  • Systems requirements review

    The mission’s requirements and concept of operations are reviewed end to end at SRR.

  • Critical design review

    The detailed design review before the payload build

  • Launch!

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Work with us

We welcome collaboration on target selection, ground-based supporting spectropolarimetry, and grain-alignment modelling. Students/Postdocs interested in working on UV instrumentation can get in touch with either PI, Deputy PI or Science PI.

Contact

Principal Investigator
Ramya Anche — University of Arizona
ramyaanche@arizona.edu
Deputy PI
Kyle Van Gorkom — University of Arizona
kvangorkom@arizona.edu
Science PI
B-G Andersson — McDonald Observatory, UT Austin
bgandersson@austin.utexas.edu