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Alan Jackson

Asst Research Scientist (FSC)
Academic Professional, TEMPE Campus, Mailcode 6004
Biography: 

I am an astronomer and planetary scientist and one of the Exploration Fellows in the School of Earth and Space Exploration. My research revolves around the formation and evolution of planets and the planetary systems in which they reside. This is a very broad theme, and my work reflects this diversity, spanning the divide between astronomy and planetary science. The breadth of this topic also means that it touches on many different fields of expertise, and so I work closely with a wide range of other researchers. I typically approach questions from a theoretical perspective, whilst always endeavouring to link back to observational or experimental data.

Education: 
  • PhD Astronomy, University of Cambridge, UK, 2014
  • MPhys, University of Oxford, UK, 2010
Videos
SESE video on my recent work with ASU professor Steve Desch on the interstellar object 'Oumuamua
Research Interests: 

My research interests cover a wide range of topics, but the primary theme that unites them is a desire to understand the formation and evolution of planets and the systems in which they reside. The bulk of my work is theoretical in nature, making use of mathematical models and computer simulations, but I try to maintain a narrow divide between my theoretical work and observational or experimental data.

Debris and debris disks

A common thread that runs through many of my research projects is debris, the leftover flotsam and jetsam of planet formation. Though much less flashy than their planetary cousins these small, sometimes under-appreciated, bodies have an important role to play in helping us piece together the processes of planet formation, both in our own Solar system and farther afield.

Perhaps the most obvious manifestation of this is my work on circumstellar debris disks. Although an individual piece of debris is much smaller than a planet, these small bodies have a very much larger surface area-to-mass ratio which means that a disk of debris can be much more easily detectable than a planet that is several orders of magnitude more massive, in much the same way that if you blow even a small amount of flour or chalk dust into the air it can make it hard to see through. This allows us to build up a picture of the population of planetary systems in ways that is not possible with planets themselves. Moreover, large and/or nearby disks can be spatially resolved allowing us to use the structure of the disk to make inferences about the presence of planets in the system.

Giant impacts

A major topic that has been part of many aspects of my research is giant impacts. Giant impacts occur in the chaotic final stages of terrestrial planet formation when massive planetary bodies collide with one other to form the final terrestrial planets. These are some of the most violent events to occur during the planet formation process and can strongly influence the final makeup of terrestrial planets, both in terms of their mass and in terms of the proportions of elements and minerals of which they are composed. As a result of the violence of these giant impacts, in addition to producing the final planets large quantities of small debris is also released. Although giant impacts are most associated with the formation of terrestrial planets they can also occur in other parts of a planetary system. The formation of the Pluto-Charon system is most likely the result of a giant impact.

Interstellar objects

Since the discovery of 'Oumuamua in 2017 I have been fascinated by interstellar objects. These are pieces of debris from other planetary systems and provide us with the means to investigate the formation and evolution of another planetary system in more direct and detailed ways than we can achieve with our indirect observations of distant systems. Although 'Oumuamua was not discovered until after its closest approach to Earth we could for example envisage sending a space mission to a future object and possibly capturing samples of it.

 

Many of these topics are represented in the projects listed on the projects page, in addition major ambitions for the future include improving our knowledge of the size distribution of debris produced in impacts as this is a significant issue for all debris studies, and reducing our reliance on computationally intensive N-body simulations.

In the past I have also studied the evaporation of planetary atmospheres under the influence of high-energy radiation, and maintain an interest in the physics of planetary atmospheres and their evolution.

Publications: 
  1. 1I/‘Oumuamua as an N2 ice fragment of an exo-pluto surface I: Size and Compositional Constraints

    Jackson A.P., Desch S.J., 2021, Journal of Geophysical Research, in press

     

  2. 1I/‘Oumuamua as an N2 ice fragment of an exo-pluto surface II: Generation of N2 ice fragments and the origin of ‘Oumuamua

    Desch S.J., Jackson A.P., 2021, Journal of Geophysical Research, in press

     

  3. Mid-infrared Studies of HD 113766 and HD 172555: Assessing Variability in the Terrestrial Zone of Young Exoplanetary Systems

    Su K.Y.L., Rieke G.H., Melis C., Jackson A.P., Smith P.S., Meng H.Y.A., Gáspár A., 2020, Astrophysical Journal, 898, 21

     

  4. HD 145263: Spectral observations of silica debris disk formation via extreme space weathering?

    Lisse C.M., Meng H.Y.A., Sitko M.L., Morlok A., Johnson B.C., Jackson A.P., Vervack R.J. Jr., Chen C.H., Wolk S.J., Lucas M.D., Marengo M., Britt D.T., 2020, Astrophysical Journal, 894, 116

     

  5. Automated crater shape retrieval using weakly-supervised deep learning

    Ali-Dib M., Menou K., Jackson A.P., Zhu C., Hammond N., 2020, Icarus, 345, 113749

     

  6. Gravity dominated collisions: a model for largest remnant masses with treatment for ‘hit and run’ and density stratification

    Gabriel T.S.J., Jackson A.P., Asphaug E., Reufer A., Jutzi M., Benz W., 2020, Astrophysical Journal, 891, 40

     

  7. Can a machine learn the outcome of planetary collisions?

    Valencia D., Paracha E., Jackson A.P., 2019, Astrophysical Journal, 882, 35

     

  8. Oort cloud asteroids: collisional evolution, the Nice Model and the Grand Tack

    Shannon A., Jackson A.P., Wyatt M.C., 2019, Monthly Notices of the Royal Astronomical Society, 485, 5511

     

  9. Extreme debris disk variability: exploring the diverse outcomes of large asteroid impacts during the era of terrestrial planet formation

    Su K.Y.L, Jackson A.P., Gáspár A., Rieke G.H., Dong R., Olofsson J., Kennedy G.M., Leinhardt Z.M., Malhotra R., Hammer M., Meng H.Y.A., Rujopakarn W., Rodriguez J.E., Pepper J., Reichart D.E., James D., Stassun K.G., 2019, Astronomical Journal, 157, 202

     

  10. Lunar crater identification via machine learning

    Silburt A., Ali-Dib M., Chenchong Z., Jackson A.P., Valencia D., Kissin Y., Tamayo D., Menou K., 2019, Icarus, 317, 27

     

  11. Effect of re-impacting debris on the solidification of the lunar magma ocean

    Perera V., Jackson A.P., Elkins-Tanton L.T., Asphaug E., 2018, Journal of Geophysical Research: planets, 123, 1168

     

  12. Ejection of rocky and icy material from binary star systems: Implications for the origin and composition of 1I/`Oumuamua

    Jackson A.P., Tamayo D., Hammond N., Ali-Dib M., Rein H., 2018, Monthly Notices of the Royal Astronomical Society Letters, 478, 49

     

  13. Dynamical and biological panspermia constraints within multi-planet exosystems

    Veras D., Armstrong D.J., Blake J.A., Gutiérrez-Marcos J.F., Jackson A.P., Schäeffer H., 2018, Astrobiology, 9, 18

     

  14. Constraints on the pre-impact orbits of Solar System giant impactors

    Jackson A.P., Gabriel T.S.J., Asphaug E., 2018, Monthly Notices of the Royal Astronomical Society, 474, 2924

     

  15. The Taurus boundary of stellar/sub-stellar (TBOSS) survey II: Disk masses from ALMA continuum observations

    Ward-Duong K., Patience J., Bulger J., van der Plas G., Menard F., Pinte C., Jackson A.P., Bryden G., Turner N.J., Harvey P., Hales A., de Rosa R.J., 2018, Astrophysical Journal, 155, 54

     

  16. How to design a planetary system for different scattering outcomes: giant impact sweet spot, maximising exocomets, scattered disks

    Wyatt M.C., Bonsor A., Jackson A.P., Marino S., Shannon A., Monthly Notices of the Royal Astronomical Society, 2017, 464, 3385

     

  17. Gas and dust around A-type stars at tens of Myr: signatures of cometary breakup

    Greaves J. S., Holland W. S., Matthews B. C., Marshall J. P., Dent W. R. F., Woitke P., Wyatt M. C., Matrà L., Jackson A.P., Monthly Notices of the Royal Astronomical Society, 2016, 461, 3910

     

  18. The spherical Brazil nut effect and its significance to asteroids

    Perera V., Jackson A.P., Asphaug E., 2016, Icarus, 278, 194

     

  19. Insights into planet formation from debris disks: II. Giant impacts in extrasolar planetary systems

    Wyatt M.C., Jackson A.P., in The disk in relation to the formation of planets and their proto-atmospheres, eds. Falanga M., Rodrigo R., Blanc M., Lammer H., International Space Science Institute – Beijing, 2016, also at Space Science Reviews, 2016, 205, 231

     

  20. Eight billion asteroids in the Oort cloud

    Shannon A., Jackson A.P., Veras D., Wyatt M.C., 2014, Monthly Notices of the Royal Astronomical Society, 446, 2059

     

  21. Debris from giant impacts between planetary embryos at large orbital radii

    Jackson A.P., Wyatt M.C., Bonsor A., Veras D., 2014, Monthly Notices of the Royal Astronomical Society, 440, 3757

     

  22. Molecular Gas Clumps from the Destruction of Icy Bodies in the β Pictoris Debris Disk

    Dent W.R.F., Wyatt M.C., Roberge A., Augereau J.-C., Casassus S., Corder S., Greaves J.S., de Gregorio-Monsalvo I., Hales A., Jackson A.P., Hughes A.Meredith, Lagrange A.-M., Matthews B., Wilner D., 2014, Science, 343, 1490

     

  23. Debris from terrestrial planet formation: the Moon-forming collision

    Jackson A.P., Wyatt M.C., 2012, Monthly Notices of the Royal Astronomical Society, 425, 657

     

  24. Planetary evaporation by UV & X-ray radiation: basic hydrodynamics

    Owen J.E., Jackson A.P., 2012, Monthly Notices of the Royal Astronomical Society, 425, 2931

     

  25. The coronal X-ray-age relation and its implications for the evaporation of exoplanets

    Jackson A.P., Davis T.A., Wheatley P.J., 2012, Monthly Notices of the Royal Astronomical Society, 422, 2024