Bryce T. Bolin

Postdoctoral Scholar in Astronomy - Caltech/IPAC

Welcome! I am a postdoctoral researcher in the division of astronomy at Caltech and at IPAC. My research focuses on observations of asteroids and comets in the Solar System with wide-field surveys as well as their follow-up with ground and space-based facilities. Please see the other sections of my site for more information and feel free to contact me here if you have questions regarding my work.


About me

I graduated in mid-2018 with a Ph.D. in astrophysics from l'Université Côte d'Azur where the topic of my thesis was on the dynamics of asteroid families and identifying the oldest asteroid families.  Before studying in France, I was a research analyst at the University of Hawaii's Institute for Astronomy where I worked with the Pan-STARRS survey on near-Earth asteroid observations, the observability of temporarily captured asteroids, and asteroid survey selection effects for next-generation near-Earth asteroid Models.

Now, as a postdoc, I have returned to my roots, hunting asteroids and comets with the Zwicky Transient Facility at Palomar Observatory where I am the Solar System working group lead. I am also the Inner Solar System working group lead for the LSST Solar System Science Collaboration. Please see my Research and Publications pages for more details about my work.



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Survey observations of near-Earth, near-Sun asteroids and comets

I have led or participated in the discovery of over ~450 near-Earth asteroids and ~50 comets through my involvement in minor body observations with the Zwicky Transient Facility and Pan-STARRS survey projects. Highlights include the discovery of the first-known inner-Venus object, 2020 AV2 (orbital diagram above, discovery circular Bolin et al. 2020a, MPEC 2020-A99 and Caltech press release here), one of the closest asteroids to pass by the Earth, 2020 QG (orbital diagram above, discovery circular Bolin et al. 2020b, MPEC 2020-Q51 and NASA press release here), and active asteroidsP/2013 P5 (Bolin et al. 2013, CBET #3639) and P/2013 R3 (Hill et al. 2013, CBET #3658).  In addition, I was involved in the creation of the next-generation near-Earth object model (Granvik et al. 2016, Nature, 530, 7590, pp. 303-306, Granvik et al. 2018, Icarus, 312, p. 181-207, and Morbidelli et al. 2020, Icarus, 340, 113631) using a method I co-developed to quantify the selection effects of ground-based surveys (Jedicke et al. 2016, Icarus, 266, p. 173-188). 

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Characterization of interstellar objects and transitioning bodies

The discovery of 1I/ʻOumuamua in the Fall of 2017 kicked off the field of interstellar objects study. My team and I were one of the first groups to observe its large amplitude lightcurve indicating its highly-elongated shape (Bolin et al. 2018a, ApJL,852,1,2). The astronomical world was shocked once again at the discovery of the second interstellar object 2I/Borisov which had a clearly active appearance compared to 1I which my team characterized with both ground (Bolin et al. 2020c, AJ, 160, 1, 16 pp.) and space-based (Bolin & Lisse 2020, MNRAS, 497, 4, p. 4031-4041) facilities indicating the volatile species driving its activity and its spin axis orientation. Initially classed as a Jovian Trojan, active Centaur P/2019 LD2 is in the process of transitioning into becoming an inner-Solar system comet within the next few decades before being ejected from the Solar System. This transitioning class of comet gives us the opportunity to characterize the recent start of its activity (Image above taken with Hubble on 2020 April 1 above, Bolin et al. 2021, 161, 3, 15 pp.) as it enters the inner Solar System with NASA's great observatories Hubble and Spitzer in addition to ground-based facilities such as ZTF and Keck.

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Identifying asetoroid families

There is a well-known discrepancy in the observed number of asteroid families with ages over two billion years old compared to the number of younger asteroid families. One possible resolution to the discrepancy is that older families are more difficult to detect due to the dispersal of their family fragments over time by secular gravitational interactions with the other bodies of the Solar System and due to non-gravitational forces such as the Yarkovsky effect. My Ph.D. research was to develop a method of detecting asteroid families that were resilient to the processes of dispersing family fragments over secular time-scales called the "V-shape method" (synthetic asteroid family V-shape in image above, see Bolin et al. 2017, Icarus, 282, p. 290-312). This method was applied to a portion of asteroids in the inner-Main Belt which revealed the presence of a previously unknown >4 billion-year-old asteroid family (Delbo' et al. 2017, Science, 357,  6355, 1026-1029). The discovery of this primordial family suggests that all dark asteroids in the inner-Main Belt may share a common origin and that some of the original planetesimals remain in the current day Main Belt. Additional modifications to the V-shape method were used to study size-dependent variations in the physical properties of family fragments, such as thermal inertia (Bolin et al. 2018b, A&A, 611, A82, 27 pp.) as well as the initial ejection velocity of family fragments (Bolin et al. 2018c, MNRAS, 473, 3, p.3949-3968).


Temporarily captured asteroids AKA "minimoons"

Temporarily-captured asteroids, or "minimoons", are captured from the smallest members of the NEO population. At any given time, there are 1-2 meter-scale minimoons in orbit around the Earth (Jedicke et al. 2018, FrASS, 5, 13, p. 13). As of today, there are only two known examples of minimoons, 2006 RH120 and 2020 CD3, both discovered by the Catalina Sky Survey. Present-day all-sky surveys may be able to discover 1-2 minimoons per decade (sample orbital trajectory in the left panel above), but coming all-sky surveys such as Rubin Observatory may be able to discover one every 1-2 months (Bolin et al. 2014, Icarus, 241, p. 280-297). Minimoons represent the smallest members of the known NEO population about which the physical details are sparsely known. Following its discovery, we observed 2020 CD3 with Keck (V band image from the Keck observations in the right panel above) and obtained spectrophotometry of the 1 m size asteroid with wavelengths ranging between 400 nm and 1000 nm. Our observations revealed that the object had a natural origin and a V-type-like spectrum (Bolin et al. 2020d, ApJL, Volume 900, Issue 2, id.L45, 14 pp.) with a minutes-long rotation period making 2020 CD3 one of the smallest asteroids to be physically characterized.



References and Links to Papers

Please see the complete list of my publications on NASA/ADSGoogle Scholar, or arXiv.

For a list of my IAU Minor Planet Center circulars, please see here.




  • Ph.D. in Astrophysics, Université Côte d'Azur, 2018

  • M.S. in Physics, University of Central Florida

  • B.S. in Physics, University of Florida

Postdoctoral Fellow

  • Postdoctoral Fellow, Department of Astronomy, University of Washington, 2019

  • Postdoctoral Scholar in Astronomy, Division of Physics, Mathematics and Astronomy, California Institute of Technology/IPAC, 2019 - Present

Please see my full CV here.


Press coverage of my work

Characterization of transitioning Centaur P/2019 LD2 with NASA's Great Observatories

February 25, 2021

Discovery of 2020 QG, one of the closest asteroids to fly-by the Earth

August 18, 2020

Fragmentation of Interstellar Comet 2I/Borisov

April 7, 2020

Discovery of the first inner-Venus asteroid, 2020 AV2

January 15, 2020

Size and Carbon Monoxide-driven activity of 2I/Borisov

October 29, 2019