Postdoctoral Scholar
University of California
Santa Barbara, California, USA
rociokiman at gmail dot com
I'm a Postdoctoral Scholar at the University of California, Santa Barbara.
I study low-mass stars, brown dwarfs and exoplanets. I'm interested in stellar ages, and formation and evolution of giant exoplanets. In particular I study how host stellar properties like age, magnetic activity, rotation and composition can help understand exoplanets atmospheres and formation. Moreover I'm interested in science outreach, to make Physics and Astronomy accessible to the public.
A detailed list of my publications can be found on ADS and Google Scholar.
Contact: rociokiman at gmail dot com.
Last updated December 2025.
Below is a summary of my top 5 publications. See the full list on ADS and Google Scholar.
I studied the system COCONUTS-2 composed of an M3 dwarf star and a giant planet (7.5 MJup) widely separated. I confirmed that the system belongs to the CUMA association. Combining the age with a JWST/NIRSpec spectrum of COCONUTS-2b I calculated its metallicity and C/O. The comparison to the rest of the members of the group, showed that it likely formed with the same mechanism as stars. See the full study in Kiman et al. 2025.
I calibrated the Gaia surface brightness-color relation which allows to estimate radius of FGK and M stars. This is a precise and model independent radius. I used this calibration to study radius inflation on M dwarfs and its relation to magnetic activity. The paper is published in Kiman et al. 2024, and I made a tutorial on how to use the relations to estimate radius.
I developed an open source Python package called wdwarfdate to estimate white dwarf ages from an effective temperature and a surface gravity in a Bayesian framework. For a description of the code read Kiman et al. 2022. The source of wdwarfdate can be found in GitHub, and the documentation of the code plus tutorials on how to use it can be found here.
I characterized the Hα Age-Activity relation for M dwarfs using a sample of age-calibrators with Halpha equivalent widths from the literature. I obtained their ages from known moving groups and white dwarfs co-movers. Read my paper Kiman et al. 2021 to learn more about this work.
I collected a sample of 74,216 M and L dwarfs with Hα measurements and Gaia DR2 photometry, parallaxes and proper motions. Using this sample I found relations between age indicators and the position in the CMD. Find more about the sample in my paper Kiman et al. 2019. And reproduce this CMD and more with this jupyter notebook.
I developed the following tutorials on how to use the modeling methods in the Python package astropy:
I am part of the Astronomy Outreach department at the California Institute of Technology (Caltech). As a member, I have given public talks in events like Astronomy on Tap and the Stargazing Lecture (in Spanish). I have also participated and help organize events with different activities to interact with the public at events like the Pasadena Science Fair and the International Astronomy Day at Santa Barbara. In addition, I participated of a week long outreach trip for the annular solar eclipse in 2023 to Grand Canyon, North Rim and Bryce Canyon National Park where I gave an Astronomy on Tap talk, participated on Star Parties where we used telescopes to show different objects (like Saturn and Jupiter) to the public and talk about astronomy, and participated on a Q&A panel. In April 2024, I co-organized a two day event for the total solar eclipse in Piedras Negras, Mexico, in collaboration with the Instituto Tecnologico de Piedras Negras, for around 2000 people. We organized public talks, a star party and a viewing event of the eclipse for the local community. See a summary of the event here here.
During July 2022, I was a volunteer at the Santa Barbara Museum of Natural History. I got to develop a planetarium show about our Solar System and I performed it in Spanish every week. See an interview about my experience for the Kavli Institute for Theoretical Physics Newsletter here.
During my Ph.D., as a member of the American Museum of Natural History (AMNH) Astronomy department, I had several key opportunities to interact with middle and high school students participating in museum outreach events. These included speaking with small visiting classes from ESL (English as a second language) schools and running an astronomy booth for local visiting families at an all-Spanish planetarium program.
During my undergraduate studies, I joined the outreach group at the University of Buenos Aires (UBA) where I participated in different events to take science to the public such as: “Physics week” and “Museum Night”. During these events we had exhibitions with physics experiments for middle and high school students, and the general public. I also participated in monthly meetings with groups of high school students to explain to them what the Physics career is about and what it means to be a scientist.