arXiv subjects

Kelly Lepo

Publications and source records attributed to Kelly Lepo.

3 recordsLinked to original sources

arXiv2026

The Astrosky Ecosystem: An independent online platform for science communication and social networking

While almost everything that astronomers study occurs in the vacuum of space, astronomy itself does not `happen in a vacuum'. Interactions between scientists, as well as outreach to members of the public, improve extensively from access to good communication tools. Social media has become a key tool for communication in astronomy, being widely used by individuals and organizations alike for networking, outreach, and more. However, traditional social media is reliant on benevolent corporations providing a free service without compromising on quality, and the recent takeover and decline of Twitter has shown how vulnerable these platforms can be. In this proceeding, we present The Astrosky Ecosystem, which is an initiative to develop open-source tools and integrations for social media, principally the Bluesky social network. We explain how our project enables the astronomy community to operate its own social media infrastructure, independent of for-profit corporations. We also discuss some of the project's technical aspects, including its use of the AT Protocol for social networking, before concluding with ideas for the future.

astro-ph.IM↗

arXiv2013

Rapidly accreting white dwarfs as supernova type Ia progenitors

The nature of the progenitors of type Ia supernovae is still a mystery. While plausible candidates are known for both the single degenerate and double degenerate models, the observed numbers fall significantly short of what is required to reproduce the type Ia supernovae rate. Some of the most promising single-degenerate type Ia progenitors are recurrent novae and super-soft sources (SSS). White dwarfs with higher mass transfer rates can also be type Ia supernova progenitors. For these rapidly accreting white dwarfs (RAWD), more material than is needed for steady burning accretes on the white dwarf, and extends the white dwarf's photosphere. Unlike super-soft sources, such objects will likely not be detectable at soft X-ray energies, but will be bright at longer wavelengths, such as the far ultraviolet (UV). Possible examples include LMC N66 and the V Sagittae stars. We present a survey using multi-object spectrographs looking for RAWD in the central core of the SMC, from objects selected to be bright in the far UV and with blue far UV-V colors. While we find some unusual objects, and recover known planetary nebula and WR stars, we detect no candidate RAWD. The upper limits from this non-detection depending on our expectations of what a RAWD should look like, as well assumptions about the internal extinction of the SMC. Assuming they resemble LMC N66 or fainter versions of Wolf-Rayet stars we set an upper limit of 10-14 RAWD in the SMC. However, our survey is unlikely to detect objects like V Sge, and hence we cannot set meaningful upper limits if RAWD generally resemble these.

astro-ph.SR↗

arXiv2011

Ultra-soft sources as supernova type Ia progenitors

Missing from the usual considerations of nuclear burning white dwarfs as Type Ia supernova progenitors are systems with very higher mass transfer rates, where more material than is needed for steady burning accretes on the white dwarf. This will move out the photosphere of the white dwarf, causing it to emit at longer wavelengths. Thus, we propose the name ultra-soft source (USS) for these objects. We present a VLT/FLAMES survey looking for USS in the SMC, selected to be bright in the far UV and with blue far UV-V colors. While we find some unusual objects, and recover known planetary nebula and WR stars, we detect no objects with strong He II lines, which should be a signature of USS. This null result either puts an upper limit on the number of USS in the SMC, or shows that we do not understand what the optical spectra of such objects will look like. We also discuss the unusual LMC [WN] planetary nebula LMC N66 as a possible example of an USS. It has a luminosity consistent with that expected, and its spectra show incompletely CNO-processed material - strong helium lines, some hydrogen, enhanced nitrogen and depleted carbon. It also shows periodic outbursts. USS may resemble N66 in quiescence. However, it lacks a FUV excess, contrary to our predictions.

astro-ph.SR↗