Speaker
Alessandra Migliorini
(INAF)
Description
The optical band is an interesting spectral region to explore the solar system objects. In this range,
indeed, it is possible to investigate properties of several molecules that are of interest for comets and
distant objects, like Kuiper Belt Objects (KBOs).
WST, in its present configuration, allows one to cover emissions from a list of radicals, including CN,
N2
+, CO+, C2, NH2, and OI, that are relevant to provide indication on the relative abundance of parental
molecules, in comets. As an example, N2
- and CO+ can be used to infer the relative N2 and CO content,
which is finally a very sensitive indicator of their formation temperatures, only studied on a few objects
so far. On the other hand, by extending the wavelength coverage to 300 nm, it would be possible to study
the water outgassing taking advantage of the very bright OH (0-0) emission band around 310 nm
(Snodgrass et al., 2017).
Triton, Pluto and possibly the KBOs, another class of solar system objects that can be studied with
WST, are thought to have a similar surface composition, rich in volatile ices, including N2, H2O, CO2,
CO, and CH4 (Buratti et al. 1994; Quirico et al. 1999; Cruikshank et al. 2000; Grundy and Young,
2004; Grundy et al. 2010; Demeo et al., 2010), and dominated by N2. Thanks to the monitoring efforts
using ground-based observations in the visible and near-infrared, short (Hicks and Buratti, 2004) and
long-term variability (Grundy and Young, 2004) of the major components have been reported for
Triton. Of particular interest is the use of CH4 bands to investigate the surface composition and help
predicting the seasonal evolution of volatile species across the surface.
In this work, we explore the capabilities of WST to investigate the surface composition of comets and
KBOs. The strength point of WST for the solar system objects investigation is the use of the 300-400
nm range, not covered by any of the future giant telescopes, which will permit to investigate most of
the radical produced by the surface sublimation on comets. In addition, the advantage of the large
Field of View of WST will allow to possibly setting up a survey of a wide number of KBOs, with a
twofold purpose: enlarge the number of KBO spectrally characterized, allowing a statistical spectral
study of the distant Solar System, and provide a reliable sample for a comparative investigation with
the Triton surface composition.
The use of WST for these science topics will burst our knowledge on KBOs and comets, particularly in
the Comet Interceptor era.
Author
Alessandra Migliorini
(INAF)
