arXiv subjects

Nicolle Zellner

Publications and source records attributed to Nicolle Zellner.

7 recordsLinked to original sources

arXiv2026

An 800-Million-Year-Old Impact Shower on the Terrestrial Planets from the Breakup of the Eulalia Parent Body

Multiple studies have proposed a substantial surge in large lunar impacts approximately $800$ million years ago (Ma). Some are based on analyses of the ages of large lunar craters, such as the $93$ km Copernicus crater. Others focus on the age distributions of impact glasses returned by lunar missions. A key challenge has been identifying and testing a plausible source for this putative impact spike. Here we use collisional and dynamical models to link this event to the formation of the Eulalia asteroid family, whose primitive carbonaceous chondrite-like parent body disrupted $\sim 800$ Ma near the 3:1 mean motion resonance with Jupiter (J3:1). Our simulations indicate that approximately three-quarters of the family's fragments eventually entered the J3:1 over a $\sim 150$-million year interval. While some fragments were injected into the resonance immediately after the disruption, others migrated more gradually via non-gravitational (Yarkovsky) thermal forces. Once in the J3:1, the fragments were dynamically transported into the planet-crossing region, leading to an elevated rate of bombardment on the Moon and terrestrial planets. Our results demonstrate that the Eulalia breakup can plausibly account for the observed lunar craters formed near $800$ Ma. Intriguingly, this event may also have had widespread repercussions across the inner Solar System. On Earth, its timing coincides with significant shifts in the biosphere, possibly linked to large impacts. On Mars, these impacts might have triggered a pulse of volcanic activity. Together, they showcase how certain catastrophic collisions in the main belt can have far-reaching consequences for the history of the terrestrial planets.

astro-ph.EP↗

arXiv2025

Recommended Actions for the American Astronomical Society: CSWA's Perspective on Steps for a more Inclusive Astronomy -- II. Recommendations

This paper, the second in a series of two, provides a set of recommendations that the American Astronomical Society (AAS) can take to create a more diverse and inclusive professional society for astronomers, with a focus on women astronomers. As noted in Paper I, now is the time for the AAS to take decisive action to transform astronomy into a diverse and inclusive profession. By combining the results of our 2019 survey, which is described in Paper I, peer-reviewed academic literature, and findings from many of the white papers submitted to Astro2020, the CSWA has developed 26 specific actions the AAS can take to help end harassment and bullying in astronomy; advance career development for astronomers who are women, members of other underrepresented groups, and intersections of these populations; and improve the climate and culture of AAS meetings. Actions to reduce rates of harassment and bullying include improvements to the AAS's anti-harassment policies and procedures and the development of astronomy-specific anti-harassment training resources. Actions to advance career development include creating a compensation database, improving how jobs are posted in the AAS Job Register, and supporting/enhancing a distance mentorship program. Finally, we call on the AAS to continue improving the accessibility of AAS meetings and to continue to support meeting sessions whose focus is to discuss issues of equity, diversity, and inclusion.

physics.soc-ph↗

arXiv2025

Recommended Actions for the American Astronomical Society: CSWA's Perspective on Steps for a more Inclusive Astronomy -- I. Background and Methods

In a series of two papers, we provide a comprehensive agenda of actions the American Astronomical Society (AAS) can take to create a more diverse and inclusive professional system for astronomers, with a focus on women astronomers. This first paper of the series outlines the background and methods, while the recommendations are treated in the second companion paper (Paper II). We take the stance that since the 2020 Decadal Survey (Astro2020) was delivered in 2021, with its first-ever set of recommendations on the State of the Profession, now is the time for the AAS to take decisive action to transform astronomy into a diverse and inclusive profession. In the spring of 2019, the CSWA surveyed the astronomical community to assess the popularity and feasibility of actions that the AAS can take to reduce harassment and advance career development for women in astronomy. Here we present the quantitative results of that survey and a synopsis of the free response sections, which are publicly accessible. By combining the results of our survey, peer-reviewed academic literature, and findings from many of the white papers submitted to Astro2020, the CSWA has developed 26 specific actions that the AAS can take to help end harassment in astronomy, to advance career development for astronomers who are women and who are other members of historically marginalized groups, and intersections of these populations, and to improve the climate and culture of AAS and AAS-sponsored meetings. This paper presents the data we used to make these recommendations, and the recommendations themselves will be presented in Paper II.

physics.soc-ph↗

arXiv2020

Video Killed the Writing Assignment

An introductory Astronomy survey course is often taken to satisfy a college graduation requirement for non-science majors at colleges around the United States. In this course, material that can be broadly categorized into topics related to "the sky", "the Solar System", "the Galaxy", and "cosmology" is discussed. Even with the wide variety of topics in these categories, though, students may not be 100% interested in the course content, and it is almost certain that a specific topic about which a student wishes to learn is not covered. To at least partly address these issues, to appeal to all of the students in this class, and to allow students to explore topics of their choice, a video project has been assigned to students at Albion College as a class activity. In this assignment, students are asked to create a video of a famous (or not) astronomer, astronomical object or discovery, or telescope observatory to present to the class. Students work in pairs to create a video that is original and imaginative and includes accurate scientific content. For this project, then, students use a familiar technology and exercise their creativity while learning a little (or a lot of) science along the way. Herein data on types and topics of videos, examples of videos, assignment requirements and grading rubrics, lessons learned, and student comments will be discussed and shared.

physics.ed-ph↗

arXiv2019

Astro2020 APC White Paper: Findings and Recommendations from the AAS Committee on the Status of Women in Astronomy: Towards Eliminating Harassment in Astronomy

The Committee on the Status of Women in Astronomy (CSWA) is calling on federal science funding agencies, in their role as the largest sources of funding for astronomy in the United States, to take actions that will end harassment, particularly sexual harassment, in astronomical workplaces. Funding agencies can and should lead the charge to end harassment in astronomy by the 2030 Astrophysics Decadal Survey. Anecdotal and quantitative evidence, gathered both by the CSWA and other groups, shows that harassment is prevalent and damaging for women and minority astronomers and those in related fields. Actions recommended herein will increase the rate of reporting of harassment to agencies and improve their ability to investigate and take action against harassers. We also recommend that agencies participate in harassment prevention by creating and implementing the best anti-harassment education possible. Key recommendations are: - Federal agencies should improve their ethics policies by making harassment a form of scientific misconduct. - Federal agencies should mandate that institutions report to them when a funded Principal Investigator (PI) or co-Principal Investigator (co-PI) is found to be a perpetrator of harassment. - Federal funding agencies should provide online guides to help scientists identify harassment and connect them to the right resources for making confidential or official reports. - Federal agencies should create and ensure the implementation of anti-harassment trainings by making them a requirement of receiving grant funding.

astro-ph.IM↗

arXiv2019

Astro2020 APC White Paper: Findings and Recommendations from the AAS Committee on the Status of Women in Astronomy: Advancing the Career Development of Women in Astronomy

The Committee on the Status of Women in Astronomy (CSWA) is calling on federal science funding agencies, in their role as the largest sources of funding for astronomy in the United States, to take actions that will advance career development and improve workplace conditions for women and minorities in astronomy. Funding agencies can and should lead the charge to produce excellent diversity and inclusion outcomes in our field by the 2030 Astrophysics Decadal Survey. Anecdotal and quantitative evidence, gathered both by the CSWA and other groups, shows that many structural barriers to success remain in our community. We acknowledge the success of programs like NSF-INCLUDES and NSF-ADVANCE and endorse their continued work. We also recommend further action to remove barriers to success for women and minority astronomers. Key recommendations are: - Federal agencies should push academic institutions to reconsider their support systems for scientists by requiring a high standard of pay and benefits. - Federal agencies should fund research and programs that explore and implement strategies for improving the experiences of scientists. - Federal agencies should require Principal Investigators (PIs) to provide plans for creating inclusive work environments and mentoring young scientists.

astro-ph.IM↗

arXiv2016

Persistence of Physics and Engineering Students via Peer Mentoring, Active Learning, and Intentional Advising

We have developed and implemented a low-cost peer-mentoring program that blends personal and academic support to help students achieve academic success in the introductory courses required for the Physics Major or the Dual-Degree Program in Engineering. As a result of this program, retention has increased among entering science, technology, engineering and mathematics students at Albion College as they move through the introductory classes, as shown by a 20 per cent increase in retention from first-semester to third-semester physics courses compared to years when this program was not in place.

physics.ed-ph↗