arXiv subjects

Quentin Andrew Parker

Publications and source records attributed to Quentin Andrew Parker.

4 recordsLinked to original sources

arXiv2026

Chang'e 7 Lunar Lander Optical Camera-Telescope: Optical Astronomy from the Moon

We report the design and manufacture of a new, lightweight, wide-field, optical camera-telescope on board the Chang'e 7 lunar mission (launched in August 2026 and due for lunar touchdown in late November 2026). The camera is capable of static, panchromatic imagery within a $420-696~nm$ optical wavelength range. The camera was designed and built under the small lunar astronomy observation station program of the Chinese National Space Agency (CNSA) as a collaboration between the International Lunar Observatory Association of Hawaii (ILOA), the Laboratory for Space Research (LSR) of the University of Hong Kong (HKU) and the Beijing Institute of Space Mechanics and Electricity (BISME). The camera has been built to meet science goals of the mission for sustainable astronomical operation over a large range of temperatures from the Moon's south pole. We report on the design and ground based preliminary performance, together with an analysis of the camera's simulated output to indicate the range of astronomical observations possible from the lunar surface given the camera's limited sensitivity and angular resolution given the modest aperture and wide field of view.

astro-ph.IM↗

arXiv2026

IFU Spectroscopic Study of the Planetary Nebula Abell 30: Mapping the Ionisation and Kinematic Structure of the Inner Complex

This work presents integrated flux and velocity channel maps of the planetary nebula Abell 30 (A30) inner knot system. The observations were taken with the INTEGRAL spectrograph at the William Herschel Telescope (WHT). Our IFU data cube partially covers knots J1, J2, and completely covers knots J3, J4 in the system. Optical Recombination Lines of C II, He I, He II, N III, O II and Collisionally Excited Lines of [Ar IV], [Ar V], [N II], [Ne III], [Ne IV], and [O III] were detected. Our integrated flux maps visualise the ionisation structure and the chemical inhomogeneity in the system previously reported by other groups. We find that ORLs are concentrated in the polar region (J1, J3), whereas the equatorial knots (J2, J4) are dominated by CELs. The flux ratio map of the diagnostic [O III] lambda 5007/4363 Angstrom lines reveals the electron temperature distribution, which shows cold cores of 15,000 K in knots J3 and J4 surrounded by a hot outer layer of above 20,000 K. Our channel maps show positive and negative velocity excursions from the systemic value among the ions. Several ions show variation in their velocity structures from their lower-energy-level counterparts, including [Ar IV] and [Ar V], [Ne III] and [Ne IV], and He I and He II. New recurrent velocity structures are identified in the low-density regions where the ions move much faster compared to their surrounding environments. The velocity dispersion measurements highlight extreme turbulence in some of the ions (sigma_vrad approx 140 km/s), consistent with supersonic/hypersonic motion driven by shocks. The forbidden line species [N II] exhibits lower turbulence (sigma_vrad approx 50-60 km/s), tracing denser, less-turbulent gases. Based on our data, we conclude both the ionisation and kinematic studies hint at shock heating and multiple ejection history in the evolutionary pathway of A30.

astro-ph.GA↗

arXiv2021

It Remains a Cage: Ionization Tolerance of C60 Fullerene in Planetary Nebulae

We demonstrate that by combining two robust theoretical quantum chemistry calculation techniques, stepwise ionization of C60 fullerene by UV and extreme UV photons can in principle occur up to a limit as high as q=+26 before coulomb explosion of the cage. Furthermore, these highly ionized forms exhibit a comparable structural and bonding stability as for the neutral fullerene. Certain astrophysical sources like the central stars of planetary nebulae and the hottest white dwarf stars have sufficiently hard UV radiation fields that can result in a series of highly charged C60(q+) species from q=1 up to q=16. Harsher environments, like hot X-ray bubbles in planetary nebulae, X-ray binaries and other sources, may further push the ionization right up to the q=+26 limit. These remarkable theoretical findings add new avenues to complex ion/molecule reactions, the chemistry of fragmentation products and additional pathways for spreading carbon throughout the universe. The implications for the emerging field of astrochemistry of C60 fullerene in all its possible states could be profound.

astro-ph.GA↗

arXiv2018

The Astrochemistry Implications of Quantum Chemical Normal Modes Vibrational Analysis

Understanding the molecular vibrations underlying each of the unknown infrared emission (UIE) bands (such as those found at 3.3, 3.4, 3.5, 6.2, 6.9, 7.7, 11.3, 15.8, 16.4, 18.9 mm) observed in or towards astronomical objects is a vital link to uncover the molecular identity of their carriers. This is usually done by customary classifications of normal mode frequencies such as stretching, deformation, rocking, wagging, skeletal mode, etc. A large literature on this subject exists and since 1952 ambiguities in classifications of normal modes via this empirical approach were pointed out by Morino and Kuchitsu [1]. New ways of interpretation and analyzing vibrational spectra were sought within the theoretical framework of quantum chemistry [2,3]. Many of these methods cannot easily be applied [3] to the large, complex molecular systems which are one of the key research interests of astrochemistry. In considering this demand, a simple and new method of analyzing and classifying the normal mode vibrational motions of molecular systems was introduced [4]. This approach is a fully quantitative method of analysis of normal mode displacement vector matrices and classification of the characteristic frequencies (fundamentals) underlying the observed IR bands. Outcomes of applying such an approach show some overlap with customary empirical classifications, usually at short wavelengths. It provides a quantitative breakdown of a complex vibration (at longer wavelengths) into the contributed fragments like their aromatic or aliphatic components. In addition, in molecular systems outside the classical models of chemical bonds and structures where the empirical approach cannot be applied, this quantitative method enables an interpretation of vibrational motion(s) underlying the IR bands.

astro-ph.GA↗