I have done a lot of research over the years but almost all has been planetary or solar system -based. This page has pretty much all formal research that I have done that I am no longer involved with.
Please note that you can contact me for any of the papers if you do not have access to them.
Past Post-Graduate Research: Miscellaneous || Chronology of Large (Martian) Craters and Basins
Past Graduate Research: Elliptical Crater Studies | Martian Volcanic Ages | Migration of the Tharsis Volcanic Complex on Mars | N-Body Simulations of Saturn's Rings | Arabia Terra (Mars) Formation Testing | Io Plasma Torus
Past Non-Graduate Research: Forecasting Solar Wind Speeds with Coronal Holes | Web-Based Interface for Nucleosynthesis Code
Miscellaneous, Affiliated Research
I've been involved with several different areas of research, somewhat peripherally, lately. Here are associated abstracts that don't fit into any other category.
Abstracts:
Bottke, W.F., Marchi, S., Vokrouhlicky, D., Robbins, S.J., Hynek, B.M., and A. Morbidelli. (2015) New Insights into the Martian Late Heavy Bombardment
. Lunar and Planet. Sci. Conf., 46, #1484.
Dohm, J.M. et al. (2015) The Mars Plate-Tectonic-Basement Hypothesis
Brugman, K.K., Hynek, B.M., and S.J. Robbins. (2015) Crater-Based Tests Unlock the Mystery of the Origin and Evolution of Arabia Terra, Mars
Tornabene, L.L. et al. (2015) "e;Pristine"e; Martian Craters : Part 1- Criteria and Characteristics
Piatek, J.L. et al. (2015) "e;Pristine"e; Martian Craters : Part 2- Initial Visible and Thermophysical Analyses and Results
Chronology of Large (Martian) Craters and Basins
2011-2013
Brian Hynek, William Bottke, and Robert Lillis - Collaborators
With my global crater database pretty much done, one of the most simple uses of it is to age-date features. I was interested in the chronology of the large craters and basins on the planet and wanted to know if they support the hypothesis of the Late-Heavy Bombardment, a period of time in the solar system's history that is thought to have produced a large spike of impacts on the Moon around 3.8 billion years ago. The idea is that if this happened on the Moon, then it should be evident on Mars, too.
My approach, unlike many previous ones (mostly by Herb Frey), was to use superposed craters on top of the rims of craters larger than 150 km in diameter to age-date them. So I mapped out the crater rims as well as the rims of the "obvious" basins - ones that still had some remnant of a visible rim. Five basins and 78 craters later (around 25 were too degraded to age-date), I had my results.
That culminated in the two early-2012 abstracts as well as a paper (finally published in 2013). The paper focuses on the ages and what the ages and remnant crater crustal magnetization (Bob Lillis) tell us about the magnetic dynamo. An ancillary result is to point out many issues with the current chronologies used for Mars and the inconsistencies they created in the ages assigned in this work.
Papers:
Karimi, S., Dombard, A.J., Buczkowski, D., Robbins, S.J., Williams, R.M. (2016) Using the viscoelastic relaxation of large impact craters to study the thermal history of Mars. Icarus, 272. doi: 10.1016/j.icarus.2016.02.037.
Official journal link to final version.
Lillis, R.J., Robbins, S.J., Manga, M., Halekas, J.S., and H.V. Frey. (2013) The Detectability of Impact Demagnetization at Mars: Implications for the History of the Dynamo. Journal of Geophysical Research – Planets, 118. doi: 10.1002/jgre.20105.
Official journal link to final version.
Robbins, S.J., Hynek, B.M., Lillis, R.J., and W.F. Bottke. (2013). Large impact crater histories of Mars: The effect of different model crater age techniques. Icarus, 225, p. 173–184. doi: 10.1016/j.icarus.2013.03.019.
Abstracts:
Lillis, R., Stewart, S., Roberts, J., Bottke, W., Manga, M., Frey, H., Kuang, W., and S.J. Robbins. (2014) Early Mars Chronology: When Did the Martian Dynamo Really Die? 8th Int'l. Mars Conf., 8, #TBD.
Lillis, R.J., Robbins, S.J., Manga, M., Halekas, J.S., and H.V. Frey. (2013). A New, Statistically Robust Timeline for the Martian Dynamo. Lunar and Planet Sci. Conf., 44, #1435.
Robbins, S.J.; and B.M. Hynek. (2012). Impact History of Large Bollides at Mars: Implications for the Late-Heavy Bombardment and Isochron Uncertainties
Robbins, S.J., and B.M. Hynek. (2012). Revising the Earliest Recorded Impact History of Mars and Implications for the Late Heavy Bombardment
Elliptical Crater Studies
2011-2014
Gareth Collins - Initiator || Robert Herrick - Initiator || Karl Mueller - Initiator
My global crater database contains detailed crater elliptical information. At some point I'm going to work further on categorizing it across Mars to see if there are any important and meaningful trends.
Meanwhile, Gareth Collins of the Imperial College in London wrote a paper discussing his refinement of models that predict how many elliptical craters should be present at a given diameter. The database offered him a ground-truth for Mars and so I was a co-author on that paper.
Robert Herrick of the University of Alaska in Fairbanks had completed counts of elliptical craters as a function of diameter on several outer solar system moons and he asked me to be a co-author on his paper on the subject for My Mars data. That paper was published in mid-2012.
And, Karl Mueller is interested in using crater deformation when a crater crosses a tectonic feature to understand the structure of the planet's interior (if you can deform a crater a lot, then you have a warmer and more prone-to-movement interior; and vice-versa). That paper was published in late-2014, approximately 6 years in the works.
Papers:
Mueller, K., Vidal, A., Robbins, S.J., Golombek, M., and C. West. (2014) Fault and Fold Growth in the Amenthes Uplift: Implications for Late Noachian Crustal Rheology and Heat Flow on Mars. Earth & Planetary Science Letters, 408, p. 100-109. doi: 10.1016/j.epsl.2014.09.04.
Official journal link to final version.
Herrick, R.R., Shenk, P.M., and S.J. Robbins. (2012) Surveys of Elliptical Crater Populations on the Saturnian Satellites, Mercury, and Mars. Icarus, 220, pp. 297-304. doi: 10.1016/j.icarus.2012.05.027.
Official journal link to final version.
Collins, G.S.; Davidson, T.; Elbeshausen, D.; Robbins, S.J.; and B.M. Hynek. (2011) The Size-Frequency Distribution of Elliptical Impact Craters. Earth & Planetary Science Letters, 310:1-2, pp. 1-8. doi: 10.1016/j.epsl.2011.07.023.
Abstracts:
Collins, G.S.; Davison, T.; Elbeshausen, D.; Robbins, S. J.; and B.M. Hynek. (2010). The Size-Frequency Distribution of Elliptical Craters
The Volcanic History of Mars, As Told by the Visible Calderas of Nineteen Major Volcanoes
2009-2010
Brian Hynek - Advisor || Gaetano di Achille - Collaborator
I'm fairly proud of this li'l project as it was fairly completely my idea, originally (where "originally" means that, yes, others have done it before, but not this way and it wasn't my advisor's idea and I didn't get the idea from reading of someone else doing it). One reason why this is important to me at this stage is that I've been somewhat worried that, as I pursue a career in research, I would not be able to come up with new ideas of what to research on my own or new techniques to apply to old problems. That I came up with this alone seems to indicate that I may posses that capability.
Anyway, the basic idea was to use the workflow that I had developed with my crater work to identify craters within the volcanic calderae of Mars' major volcanoes and use them to date the last visible eruptions. I used the Mars Reconnaissance Orbiter's ConteXT (CTX) camera data for this work, which lead me to learn how to use ISIS software to process and mosaic the images together.
The entire process once I actually got going was about 2.5 months from start to finish, though this was spread over 5 months due to other work and deadlines. Another goal of this project was to help me get more experience with geologic mapping - required because the calderae were not always clear where one started and another began. In truth, to speed things up, my advisor's post-doc (Gaetano) did do a significant portion of the mapping, though I had to "sign off" on everything before he sent me the maps to use.
This turned into an LPSC abstract and we wrote a paper that was accepted November 2010.
Papers:
Robbins, S.J.; Di Achille, G; and B.M. Hynek. (2011). The Volcanic History of Mars: High-Resolution Crater-Based Studies of the Calderas of Twenty Volcanoes. Icarus, 211, pp. 1179-1203. doi: 10.1016/j.icarus.2010.11.012.
Abstracts:
Robbins, S.J.; Di Achille, G.; and B.M. Hynek. (2010). Dating the Most Recent Episodes of Volcanic Activity from Mars' Main Volcanic Calderas
Robbins, S.J.; Di Achille, G.; and B.M. Hynek. (2010). Dating the Most Recent Episodes of Volcanic Activity from Mars' Main Volcanic Calderae
Geologic and Crater Evidence for the Migration of the Tharsis Mantle Plume
2010
Brian Hynek - Advisor & Primary Author || Ondrej Šrámek and Shijie Zhong - Collaborators
I contacted Shijie shortly after LPSC 2010 and my volcano paper was written and asked if anything that I had done with volcano ages would help or hurt his models for migrating mantle plumes.
The answer was "not really," but instead we went to my global crater database. Relatively quickly - over the span of about 3 months, he, Brian, and his post-doc (I think?) and I put together a short paper for Nature-Geoscience. The paper discusses the geologic (Brian), crater (me), magnetic (Ondrej), and modeling (Ondrej) evidence for the idea (Shijie) behind the mantle plume that fed and created the vast Tharsis volcanic province migrating thousands of kilometers from the martian south pole towards the equator, where it is today.
Rejected from the first journal due to length issues and a misunderstanding on magnetic field data, we expanded and fixed parts of it and re-submitted the paper to Earth & Planetary Science Letters where it was published. My advisor prepared a 2011 LPSC abstract for the work (citation below).
Papers:
Hynek, B.M.; Robbins, S.J.; Šmárek, O.; and S. Zhong. Geological Evidence for a Migrating Tharsis Plume. Earth & Planetary Science Letters, 310, pp. 327-333. doi: 10.1016/j.epsl.2011.08.020.
Abstracts:
Hynek, B.M., Robbins, S.J.; Šrámek, O.; and S. Zhong. (2011). Geological Evidence for a Migrating Tharsis Plume on Early Mars
High-Optical Depth N-Body Simulations of Saturn's Rings
2006, 2008-2009
Glen Stewart - Advisor
This work was started back in 2006, where I was to basically explore the properties of Saturn's rings on the scale of ~10-500 meters through N-body simulations and how they changed with distance from Saturn (B ring at 100 Mm and A ring at 130 Mm) and optical depth.
This evolved into a project (after I started working on Mars, and then later when I got a much faster computer for myself that could actually do these simulations in a realistic time frame) where I have explored a large parameter space of over 190 simulations showing different distances from Saturn, internal particle density, different size distributions of particles, and especially different optical depths.
The key, big-picture finding from this is that Saturn's rings are very effective at "hiding" material in self-gravity wakes and clumps. So while I can keep increasing the amount of material (number of particles) in a fixed space, the resulting optical depth hardly increases at all. This has serious implications for the overall mass of the rings, since estimating the mass required to get an observed optical depth is how it's pretty much done. The simulations so far have shown that the mass of the rings is - conservatively - at least 2 times more than has been previously estimated. This then has implications for the age of the rings as more massive rings are more likely to be older (for several reasons, but not ones that I study).
My paper is in the Icarus special edition of "Cassini at Saturn," April 2010. I also have two DPS abstracts from this, one from 2007, and the other from 2008. I may at some point mine the data for enough to get a second paper from this, though that is increasingly unlikely as the months roll on.
Papers:
Robbins, S.J., Stewart, G.R., Lewis, M.C., Colwell, J.E., and M. Sremčević. (2010). Estimating the Masses of Saturn's A and B Rings from High-Optical Depth N-Body Simulations and Stellar Occultations. Icarus, 206, p. 431-445. doi: 10.1016/j.icarus. 2009.09.012.
Abstracts:
Robbins, S.J., Stewart, G.R., Colwell, J.E., and M.C. Lewis. (2008) Self-Gravity Wakes in Saturnian Rings: Effects of Varying Location, Particle Density and Introducing a Particle Size Distribution. Division of Planet. Sci. Meeting, pp. 424, 40:21.05.
Robbins, S.J., Stewart, G.R., Colwell, J.E., and M.C. Lewis. (2007) Simulations of Clumping Effects in High-Optical Depth Rings. Division of Planet. Sci. Meeting, 38, pp. 420.
Stewart, G.R., Robbins, S.J., and J.E. Colwell. (2007) Evidence for a Primordial Origin of Saturn's Rings. Division of Planet. Sci. Meeting, 38, pp. 420.
New Clues from Old Craters About the History of Arabia Terra, Mars
2006-2008, 2012
Brian Hynek - Advisor || Kara Brugman - Undergraduate Researcher (2012)
This was something that Brian had money for before I was awarded my NESSF. Effectively creating a localized catalog of the depth and diameter properties of the craters over ~15% of the planet, covering Arabia Terra and the neighboring Southern Highlands. The purpose was to use the craters to test hypotheses for the formation and modification history of Arabia Terra (tested two main ones). The results were that neither was confirmed and the region is still very confusing, though I have now made my own hypothetical history of the region based on the data.
I used this to get my M.S. and two conference abstracts (two more from this directly, but I have them listed under my global crater database). I will also be writing this up as a paper to submit to Icarus or JGR ... at some point. For now, we have decided it would make a good project for our undergraduate researcher, Kara.
Abstracts:
Robbins, S. J.; and B. M. Hynek. (2008). Testing Formation Theories of NW Arabia Terra, Mars: New Clues from Old Craters. LPSC XXXIX, pp. 2417. Click for the Poster.
Robbins, S.J.; Haber, R.; and B. M. Hynek. (2008). Depth/Diameter Ratios of 2.5+ km Craters in Arabia Terra, Mars, and Hints at Refining the Region's History
Io Plasma Torus Analysis
2005
Nick Schneider - Advisor
I worked on this with Nick Schneider the first summer I came to Colorado. I found it less interesting than I had thought I would, but I did at least get an authorship on a 2005 DPS abstract that I think ended up being a poster presentation.
Abstracts:
Schneider, N.M.; Robbins, S.J.; Delamere, P.A.; and A.J. Steffl. Ion Temperature Control of the Io Plasma Torus. Bulletin of the American Astronomical Society. pp. 758, 37:3 (2005).
Forecasting Solar Wind Speed from Coronal Holes
2004
Carl Henney & Jack Harvey - Advisors
This was done at an NSO REU in the summer of 2004. I worked with Carl Henney and Jack Harvey to determine if there was a way to use coronal holes (on the sun) to predict the velocity of the solar wind at Earth - basically space weather forecasting. I did get a paper out of this, published in the journal Solar Physics. I also got two abstracts and poster presentations out of it, one at the 2005 January AAS meeting and the other at the 2005 SPD meeting.
Papers:
Robbins, S. J.; Henney, C. J.; and J. W. Harvey. (2006). Solar Wind Forecasting with Coronal Holes. Solar Physics, 233, No. 2. doi: 10.1007/s11207-006-0064-y.
Abstracts:
Robbins, S. J.; Henney, C. J.; and J. W. Harvey. Solar Wind Forecasting with SOLIS-VSM. (2005). Click for the Poster.
Robbins, S. J.; Henney, C. J.; and J. W. Harvey. Solar Wind Forecasting with Coronal Holes. Bulletin of the American Astronomical Society. pp. 1350, 36:5 (2004).
Nucleosynthesis Web-Based Tools
2003
Brad Meyer - Advisors
My REU in 2003, at Clemson University through the SARA REU program. I worked with Brad Meyer and created a web-based Java interface for his nucleosynthesis code. A January 2004 AAS meeting abstract and poster was the result, along with a paper for SARA's own journal, the IAPPP. I learned Java through this, but otherwise I think it was a fairly inappropriate project for an astronomy REU as I learned no astronomy nor tools of the astronomical trade. I was just a programmer.
Papers:
Robbins, S. J.; Meyer, B. S.; and G. C. Jordan, IV. Modeling Nucleosynthesis: Web-Based Tools
Abstracts:
Robbins, S. J.; Meyer, B. S.; and G. C. Jordan, IV. Modeling Nucleosynthesis: Web-Based Tools. Bulletin of the American Astronomical Society. pp. 1209, 35:5 (2003). Click for the Poster.
