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During my PhD, I worked as part of the SPECULOOS (Search for habitable Planets EClipsing ULtra-cOOl Stars) team to optimise the detection potential of Earth-sized, habitable-zone planets transiting ultra-cool dwarfs (UCDs) from the ground. These cool, red dwarfs are small, abundant, and predicted to host a wealth of terrestrial planets. Within our current detection capabilities, these planets are also the most favourable candidates to search for traces of life. Our main goal is to provide the most promising candidates for future atmospheric characterisation by the James Webb Space Telescope (JWST). For this thesis, I focused on removing both the astrophysical and non-astrophysical sources that limit the detection of rocky planets and on constraining these planets' frequency. Firstly, I developed the SSO Pipeline, a photometric pipeline specific for the SPECULOOS Project and the ultra-cool objects that it observes. This automated pipeline carries out image reduction, cross-matches with preexisting stellar catalogues, and performs precise aperture and differential photometry every night. With the SSO Pipeline, I address both the instrumental and atmospheric contamination that can prevent detecting small planets. I tackle the first and second-order effects of the Earth's rapidly-varying atmosphere on photometric observations through specialised photometric treatment. Specifically, this pipeline removes the photometric impact of water vapour absorption by implementing a novel, first-principles correction. I optimise the performance of this pipeline through rigorous quality checking and demonstrate SPECULOOS's unprecedented precision for UCDs. I showed that SPECULOOS is reaching its survey goals in regularly achieving the required precisions to detect temperate, terrestrial planets. Secondly, due to the enhanced stellar activity of UCDs, accounting for photometric variability is an essential step in detecting rocky planets and in understanding whether these planets can initiate and sustain life. My work assesses whether this activity is beneficial or detrimental to the habitability of planetary systems around UCDs, and probes their complex magnetic behaviour. In performing a flaring and rotation study of SPECULOOS's targets, I found that the activity of the coolest stars would be too low to initiate abiogenesis or to sustain an Earth-like biosphere on their planets. By studying the activity of these targets, I mitigate the astrophysical sources of contamination in our lightcurves. Finally, I established bounds on the unexplored planetary populations around UCDs, by quantifying the detection potential of SPECULOOS for planets like TRAPPIST-1b. I developed a transit-search pipeline and performed transit injection-recovery tests to measure its detection efficiency. I concluded that worlds like TRAPPIST-1b, very short-period, rocky planets, are rare for these stellar hosts; otherwise, we would have already detected a small number. Several more years of SPECULOOS observations will be needed to confirm these results, and potentially, to find another TRAPPIST-1 system.

This thesis examines the consequences and implications of the premature deaths of royal heirs in seventeenth-century Britain. In just four generations between 1603 and 1700 the Stuart dynasty suffered the loss of over twenty-five legitimate offspring before their twenty-first year. Several of these deaths had significant political repercussions, threatening both the continuity of the royal line and consequently the security of the nation. The cultural memory of these lost heirs continued decades and even centuries later. My work seeks to establish the historical significance of their long-lasting appeal by assessing their princely representation in life and analysing its development after death. This study is firmly located within visual culture. However, definitions and classifications of the “visual” are necessarily broad. The emphasis is upon the consideration of seventeenth-century British art as part of a wider cultural process. The opening chapter addresses an apparently obvious, though somewhat neglected, issue - the critical importance of royal heirs. Through examination of the imagery and ceremonial attached to Stuart childbearing and christenings, it asserts the real symbolic significance of princely progeny. Chapter Two develops the study of youthful princely representation. It assesses the portrayal of Stuart heirs as they matured and seeks to identify the principal characteristics. Specifically, it is argued that, from a young age, the projection of Protestantism and martial aptitude was crucial to the formation of their personae. Chapter Three analyses how deceased Stuart heirs were commemorated in the months and years immediately after their deaths. It is contended that the enduring memory of these princes was the result, not of official commemoration, but of the large-scale public response to their deaths. The loss of an heir not only threatened the future of the dynasty but also the stability of the realm. The fourth chapter explores how, through visual and cultural propaganda, the surviving Stuarts attempted to re-group and to assuage social and political anxieties. Chapters Five and Six assess the long-term legacy of these princes in the decades and centuries after their deaths, as well as the political circumstances which gave rise to their enduring memory. These concluding chapters reveal the extent to which memories of deceased Stuart princes lingered, asserting that their representations were often employed for negotiation of the issues and anxieties of later ages. Throughout, my work seeks to establish the importance of these lost heirs and protectors of the Stuart Protestant line. I have endeavoured to retrieve the reputations of princes who came to represent potent symbols of both promise and loss.

By examining the material and visual culture of Jacobite exile between c.1716 and c.1760, this thesis looks more deeply into the exiled court of James VIII/III in Rome. Prompted by the theme of exile to consider less discussed elements of Jacobite history, namely the experiences of women, and the lives of Maria Clementina and Henry Benedict Stuart as members of the Stuart dynasty, the thesis offers alternative, though complementary, narratives to the dominant Jacobite histories. The artefacts discussed in this thesis are drawn largely from the rich collection of Jacobite objects at National Museums Scotland. The theme of exile provides the opportunity for a reconsideration of artefacts familiar to historians of Jacobitism - such as embroidery produced by Jacobite women - and offers scope for others - objects associated with Maria Clementina Sobieska for example - to be given more prominence in Jacobite studies. Additionally, the thesis makes sustained use of the Stuart Papers in the Royal Archives at Windsor: the letters and account books of the exiled court. These written sources enhance interpretation of extant Jacobite objects and the material experience of the Stuart court. Correspondence between Jacobites in Britain and the court in Rome illuminates the role of material culture in maintaining the affective relationship between exiled monarch and loyal subject that underpinned Jacobitism. Absent from his kingdoms and not performing the traditional functions of ruler, James VIII/III and his court used material culture to maintain the appearance of royalty in exile. Circulating images of the family, the exiled dynasty readied supporters for its eventual restoration and return. Rather than considering this use of material culture as unique to the exiled Stuarts, the thesis situates the court's practices in the wider cultural context of early-modern monarchy. While absence is inherent to exile, the thesis proposes that presence is also an essential theme. Chapters one and two consider the notable presence of the expatriate Jacobite community in eighteenth-century Roman society in the context of British tourism, antiquarianism, and art networks. Case studies of Clementina Sobieska and Henry Benedict demonstrate how the Stuarts could become fully incorporated into Roman society without relinquishing their claims to the thrones of Britain, nor the loyalty of their supporters. Examining the artefacts Jacobite women produced and consumed in response to Stuart exile, this thesis argues that material culture worked affectively to make the Stuarts present for their loyal supporters in Britain. Overall, this thesis offers a cultural history of Jacobitism focussing on the theme of exile which serves to unite Jacobitism in Rome with Jacobitism in Britain. Furthermore, this is a history which emphasises emotions as a meaningful measure of loyalty to the Jacobite cause, rather than political/military actions and the subsequent success or failure of those actions. By situating the material and visual culture of Jacobite exile in a wider eighteenth-century British and European cultural context, rather than interpreting it as peripheral to mainstream eighteenth-century history, the thesis also contributes to the history of the Grand Tour, gender studies, the history of emotions, and court culture.