Rationale

Following the success of the SuperVirtual 2021 conference last year, we are delighted to make the first announcement for SuperVirtual 2022. SuperVirtual 2022 will cover both core-collapse and thermonuclear supernovae, as well as some of the novel transients that are being found by current surveys. While in person conferences are now thankfully resuming, we hope that this online-only meeting will continue to provide a useful addition. In particular we intend for SuperVirtual 2022 to offer an opportunity to attendees who have travel or financial restrictions.

SuperVirtual 2022 aims to organise a conference that is as inclusive and participatory as possible. It is planned that both the selection of focus topics and that of contributed speakers will make significant use of participant input - more details of this will be circulated at a later date.

Please note that the time zone of the conference has been changed from 2021, and for this year we will start each day at 21:00 UTC. This is to allow those in unfavourable time zones last year to connect at a more comfortable time (while still being suitable for as many locations as possible).

Wide-field transient surveys are currently delivering large statistical samples of supernovae (SNe), while also discovering peculiar and exotic events. Samples of ‘standard’ core-collapse events afford strong constraints on their progenitor properties and explosion mechanisms. Meanwhile, the discovery of peculiar explosions often challenges our application of standard SN physics to such emerging classes. SuperVirtual 2022 will address many of these developments - providing a review of SN observations and physics, while exploring the limits of our current understanding of the processes driving SN diversity.

There is now strong consensus that the majority of hydrogen-rich SNeII arise from massive red supergiant stars. However, there is still disagreement on the exact mapping from progenitor and explosion properties to transient characteristics. The last decade has seen mounting evidence that at least a significant fraction of stripped-envelope-SNe arise from binary systems, although which envelope-mass stripping process dominates for which progenitors is still debated. In addition, it now appears that ejecta-CSM interaction is not only important for our understanding of narrow-line SNeIIn, but may also be critical for many other SN types - especially at early times in their evolution. This understanding is being enhanced by advances in survey and follow up capabilities - observations of which will be discussed at this meeting.

Knowledge of the progenitors and explosion mechanisms of SNeIa continues to grow, with larger statistical samples in addition to higher quality data of individual explosions. Such data includes observations within hrs/days of explosion, affording investigation into the prevalence of early 'excess emission' that constrains the progenitor scenario. Very late-time observations constrain the isotopic abundances produced in SNeIa, thus constraining the explosion mechanism. However, it is still unclear which progenitor systems produce the bulk of the SNIa population. This conference will provide a platform to discuss new observations, progenitor and explosion modelling, and possible future strategies to constrain the SNIa phenomenon.

The number of ‘non-standard’ SNe also continues to grow. Samples now exist of exotic explosions such as superluminous SNe (SLSNe) and SNeIbn. However, in the former it is still unclear which powering mechanism enables such large luminosities, while the properties of the latter challenge our understanding of late-time stellar evolution. Meanwhile, the diversity and number of 'peculiar' thermonuclear SNe continues to grow - from SNIax to .Ia explosions. SuperVirtual 2022 will motivate discussion on the state of the art of the explosion physics and progenitor evolution required to explain these diverse events. There are also a number of classes where only a few well-observed events exist. ‘Fast transients’ (coming in different flavours with different nomenclature - e.g. ‘FBOTs’) have timescales making them difficult to observe, but additionally have properties that are difficult to understand without invoking exotic physical scenarios. One of the most recent additions to the SN family is the SNIcn class, which further stretches the family of SNe that are significantly affected by ejecta-CSM interaction. Finally, together with these new classes, a larger number of SNe are discovered with specific features that also require an extension of any standard SN model - e.g. short timescale modulations in light curve shapes.

A full understanding of the SN phenomenon and its diversity is only possible through comparing transient observations with predictions from explosion models and stellar evolution. At SuperVirtual 2022, SN observations will be confronted with the latest modelling of stellar explosions to survey the current landscape of SNe; their numerous different classes; and their progenitor populations.