About Me

Kevin K. Hardegree-Ullman

Kevin K. Hardegree-Ullman, Ph.D.

I explore exoplanets, cool stars, brown dwarfs, and astronomy education!



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Caltech

I research exoplanets at IPAC-NExScI with Dr. Jessie Christiansen!

UT Logo

University of Toledo

I completed my Ph.D. in Physics in 2018. I conducted research with Dr. Michael Cushing.

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University of Arizona

I completed my B.S. in Astronomy with Physics and Math minors in 2011. I conducted research with Dr. Yancy Shirley.

Research: Recent Highlights

Kepler Planet Occrrence Rates for Mid-type M Dwarfs as a Function of Spectral Type

Kevin K. Hardegree-Ullman, et al. 2019. AJ, 158, 75.

Synopsis: Using updated stellar parameters from spectra and parllaxes we computed planet occurrence rates for Kepler mid-type M dwarfs. The image below shows our revised occurrence rates compared to literature values for early-type M dwarfs and FGK dwarfs.

Kepler planet occurrence rates as a function of spectral type.

Characterizing K2 Candidate Planetary Systems Orbiting Low-mass Stars. IV. Updated Properties for 86 Cool Dwarfs Observed during Campaigns 1-17

Courtney D. Dressing, Kevin K. Hardegree-Ullman, et al. 2019. AJ, 158, 87.

Synopsis: We revised stellar properties for 172 K2 planet candidate host stars, 86 of which were cool dwarfs. The image below shows how the updated stellar parameters compare to those from the EPIC.

Changes from EPIC stellar properties.

Catalog of New K2 Exoplanet Candidates from Citizen Scientists

Jon K. Zink, Kevin K. Hardegree-Ullman, et al. 2019. RNAAS, 3, 43.

Synopsis: We report 28 new K2 exoplanet candidates discovered by citizen scientists through the Exoplanet Explorers Zooniverse project. The (interactive!) plot below shows how the candidates compare to other K2 confirmed and candidate planets. Circle size indicates Kepler band magnitudes.

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Research: Multimedia

American Astronomical Society press release: Spitzer confirmation of K2-138 g.

Surely You're Joking podcast about the K2-138 exoplanet system.

Synopsis of my M dwarf research by Active Galactic Videos.

Curriculum Vitae: Kevin K. Hardegree-Ullman

Postdoctoral Scholar - Caltech/IPAC-NExScI

Contact Information

IPAC, Mail Code 100-22
Caltech
1200 E California Blvd
Pasadena, CA 91125

 

Phone: (626) 395-1874
E-mail: ude.hcetlac@uhknivek
Website: http://kevinkhu.com

Education

August 2012 to June 2018
  • Ph.D., Physics with concentration in Astrophysics
August 2006 to May 2011
  • B.S., Astronomy
  • Physics and Mathematics Minors

Research Interests

Exoplanets, cool stars, brown dwarfs, and astronomy education.

Research Awards

Infrared Processing and Analysis Center (IPAC) Visiting Graduate Fellowship
February to August 2017
NASA WIYN PI Data Award
Fall 2015 to Fall 2018
Graduate Research Award
April 2014

Journal Articles

Characterizing K2 Candidate Planetary Systems Orbiting Low-mass Stars. IV. Updated Properties for 86 Cool Dwarfs Observed during Campaigns 1-17
        Dressing, C. D.; Hardegree-Ullman, K. K.; et al. 2019. AJ, 158, 87.

Kepler Planet Occurrence Rates for Mid-type M Dwarfs as a Function of Spectral Type
        Hardegree-Ullman, K. K.; Cushing, M. C.; Muirhead, P. S.; Christiansen, J. L. 2019. AJ, 158, 75.

Revisiting the HIP 41378 System with K2 and Spitzer
        Berardo, D.; Crossfield, I. J. M.; et al.; (Hardegree-Ullman, K. K. 11th author) 2019. AJ, 157, 185.

Bright Opportunities for Atmospheric Characterization of Small Planets: Masses and Radii of K2-3 b, c, and d and GJ3470 b from Radial Velocity Measurements and Spitzer Transits
        Kosiarek, M. R.; Crossfield, I. J. M.; Hardegree-Ullman, K. K.; et al. 2019. AJ, 157, 97.

Catalog of New K2 Exoplanet Candidates from Citizen Scientists
        Zink, J. K.; Hardegree-Ullman, K. K.; et al. 2019. RNAAS, 3, 43.

Characterizing K2 Candidate Planetary Systems Orbiting Low-Mass Stars III: A High Mass & Low Envelope Fraction for the Warm Neptune K2-55b
        Dressing, C. D.; Sinukoff, E.; et al.; (Hardegree-Ullman, K. K. 23rd author) 2018. AJ, 156, 70.

Planetary Candidates from K2 Campaign 16
        Yu, L.; Crossfield, I. J. M.; et al.; (Hardegree-Ullman, K. K. 19th author) 2018. AJ, 156, 22.

Spitzer Light Curves of the Young, Planetary-Mass TW Hya Members 2MASS J11193254-1137466AB and WISEA J114724.10-204021.3
        Schneider, A. C.; Hardegree-Ullman, K. K.; Cushing, M. C.; Kirkpatrick, J. D.; Shkolnik, E. L., 2018. AJ, 155, 238.

2MASS J11151597+1937266: A Young, Dusty, Isolated, Planetary-Mass Object with a Potential Wide Stellar Companion
        Theissen, C. A.; Burgasser, A. J.; Bardalez Gagliuffi, D. C.; Hardegree-Ullman, K. K.; et al., 2018. ApJ, 853, 75.

Investigating the Physical Properties of Transiting Hot Jupiters with the 1.5-m Kuiper Telescope
        Turner, J. D.; Leiter, R. M.; Biddle, L. I.; Pearson, K. A.; Hardegree-Ullman, K. K.; et al., 2017. MNRAS, 472, 3871.

The Most Massive Heartbeat: An In-Depth Analysis of Iota Orionis
        Pablo, H.; Richardson; N. D.; et al.; (Hardegree-Ullman, K. K. 18th author) 2017. MNRAS, 467, 2494.

A Spectroscopic Orbit for the Late-type Be Star Beta CMi
        Dulaney, N. A.; Richardson, N. D.; et al.; (Hardegree-Ullman, K. K. 12th author) 2017. ApJ, 836, 112.

Photometric Monitoring of the Coldest Known Brown Dwarf with the Spitzer Space Telescope
        Esplin, T. L.; Luhman, K. L.; Cushing, M. C.; Hardegree-Ullman, K. K.; et al., 2016. ApJ, 832, 58.

Observed Variability at 1μm and 4μm in the Y0 Brown Dwarf WISEP J173835.52+273258.9
        Leggett, S. K.; Cushing, M. C.; Hardegree-Ullman, K. K.; et al., 2016. ApJ, 830, 141.

Ground-Based Near-UV Observations of 15 Transiting Exoplanets: Constraints on Their Atmospheres and No Evidence for Asymmetrical Transits
        Turner, J. D.; Pearson, K. A.; Biddle, L. I.; Smart, B. M.; Zellem, R. T.; Teske, J. K.; Hardegree-Ullman, K. K.; et al., 2016. MNRAS, 459, 789.

The First Detection of Photometric Variability in a Y Dwarf: WISE J140518.39+553421.3
        Cushing, M. C.; Hardegree-Ullman, K. K.; et al., 2016. ApJ, 823, 152.

Near-UV and Optical Observations of the Transiting Exoplanet TrES-3b
        Turner, J. D.; Smart, B. M.; Hardegree-Ullman, K. K.; et al., 2013. MNRAS, 428, 678.

Observing Time Awarded as PI

WIYN
46 nights
NASA IRTF
12 nights

Astrophotography

This is a collection of astronomical images I've taken recently at Ritter Observatory, the Discovery Channel Telescope, and other areas of Arizona and Ohio. Please contact me if you want a full-resolution version or if you would like to use any of these images for any purpose.

M1 - Crab Nebula

M1 - Crab Nebula

Ritter Observatory

M13 - Hercules Cluster

M13 - Hercules Cluster

Ritter Observatory

M16 - Eagle Nebula

M16 - Eagle Nebula

Ritter Observatory

M27 - Dumbbell Nebula

M27 - Dumbbell Nebula

Ritter Observatory

M42 - Orion Nebula

M42 - Orion Nebula

Ritter Observatory

M57 - Ring Nebula

M57 - Ring Nebula

Ritter Observatory

M82 - Cigar Galaxy with SN2014J

M82 - Cigar Galaxy with SN2014J

Ritter Observatory

Horsehead Nebula

Horsehead Nebula

Discovery Channel Telescope

Pointing to the center of the Milky Way

Pointing to the center of the Milky Way

Near Assumption, Ohio

Camelopardalid Meteor Shower

Camelopardalid Meteor Shower

Near Assumption, Ohio

Observing at the DCT

Observing at the DCT

Discovery Channel Telescope

Annular Eclipse

Annular Eclipse

Horseshoe Bend, Arizona - May 20, 2012

Venus Transit - Mt. Lemmon SkyCenter, Arizona - June 5, 2012