Donna M. Pierce's research while affiliated with Mississippi State University and other places
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Publications (6)
We examine the spatial distribution of C2, C3, and
NH radicals in the coma of comet Encke in order to understand their
abundances and distributions in the coma. The observations were obtained
from 2003 October 22-24, using the 2.7 m telescope at McDonald
Observatory. Building on our original study of CN and OH, we have used
our modified version of...
We have observed comet 103P/Hartley 2 using the George and Cynthia
Mitchell Spectrograph (formerly VIRUS-P) on the 2.7 m telescope at
McDonald Observatory (Hill et al. 2008). Data for CN, C2,
C3, and NH2 were collected over six nights from
2010 July 15 to November 10. The data were processed to form images of
the coma for each of the observed speci...
Multiple potential parent species have been proposed to explain CN abundances in comet comae, but the parent has not been definitively identified for all comets. This study examines the spatial distribution of CN radicals in the coma of comet Encke and determines the likelihood that CN is a photodissociative daughter of HCN in the coma. Comet Encke...
When a circular electric dipole moment, rotating in the x-y plane, is embedded in a material with relative permittivity ε(r) and relative permeability μ(r), the field lines of energy flow of the emitted radiation are dramatically influenced by the surrounding material. For emission in free space, the field lines swirl around the z axis and lie on a...
The field lines of energy flow of the radiation emitted by a linear dipole in free space are straight lines, running radially outward from the source. When the dipole is embedded in a medium, the field lines are curves when the imaginary part of the relative permittivity is finite. It is shown that due to the damping in the material all radiation i...
Understanding the sources of CO in cometary comae is important for understanding comet chemistry and the roles comets have played in the development of the solar system. Among comets sampled to date, the CO abundances vary widely and no direct correlation of CO abundance with other known comet properties has been identified. The picture is complica...
Citations
... Given the rotational variability of comets on timescales as brief as a few hours, IFU observations have the advantage of simultaneous measurements of multiple species in contrast to narrow-band observations where different filters need to be cycled to sample each species. The first observations of comets with IFUs at visible wavelengths are relatively recent (Dorman et al. 2013;Vaughan et al. 2017;Opitom et al. 2019b) but they have demonstrated the potential of this type of observation to study the spatial distributions of secondary products and their production mechanisms in the coma. ...
Reference: Chemistry of comet atmospheres
... Given the rotational variability of comets on timescales as brief as a few hours, IFU observations have the advantage of simultaneous measurements of multiple species in contrast to narrow-band observations where different filters need to be cycled to sample each species. The first observations of comets with IFUs at visible wavelengths are relatively recent (Dorman et al. 2013;Vaughan et al. 2017;Opitom et al. 2019b) but they have demonstrated the potential of this type of observation to study the spatial distributions of secondary products and their production mechanisms in the coma. ...
Reference: Chemistry of comet atmospheres
... Speculation as to the origins of this material vary since most of the O 2 known to exist in the Earths atmosphere is believed to be of biological provenance, which cannot be the case in the interplanetary medium. Prior to encounter, chemical models (Glinski et al. 2004;Pierce & A'Hearn 2010) predicted that some O 2 could be formed in the comae of comets, but not to the levels detected by Rosetta. The observations, and several suggested mechanisms for O 2 production in comet 67P, have been reviewed recently (Luspay-Kuti et al. 2018;Altwegg et al. 2019). ...
... These results were confirmed by Festou and Barale (2000). However, later (2003 apparition) Woodney et al. (2007) and Ihalawela et al. (2011) did not confirm the presence of two active areas on the surface of the comet's nucleus and instead suggested the possibility of a single active area which forms single-cone jet with an opening angle of 90 � . ...
![[object Object]](https://i1.rgstatic.net/ii/profile.image/484754018574337-1492585772206_Q64/Chandrasiri-Ihalawela.jpg)
... Therefore, vortices under the current investigation are not singular and carry no topological charges. Our key results presented in Fig. 1 display streamlines of Poynting vectors indicated by arrows [1], [2]. Here, the eye-circle indicated in green refers to a very thin layer of gain material. ...
![[object Object]](https://i1.rgstatic.net/ii/profile.image/279532843094024-1443657231580_Q64/Xin-Li-62.jpg)
... For example, in free space, the field lines of energy flow run radially outwards except for the dipole axis. In a material medium, the energy flow lines are perpendicular to the dipole axis due to damping [3]. Secondly, the experimentally measurable physical quantity is not the phase shift but rather the intensity of radiation. ...
