Jooyeon Geem (김주연)   Ph. D. student   Astronomy program   Seoul National University ORCID 0000-0002-3291-4056 Affilition Astronomy Program, Department of Physics and Astronomy, Seoul National University (SNU) Email geem@astro.snu.ac.kr  ksky0422@gmail.com   HomePage www.jygeem.com/ Github github.com/Geemjy

Research Interests

Hello, I am Jooyeon Geem, a Ph. D. student from Seoul National University (SNU) and my advisor is Prof. Masateru Ishiguro.

My curiosity lies in water in our solar system; where it is, what it looks like, and how much is there. Understanding water in our solar system is important for knowing how life works on Earth. It can also be a reference to understanding the water in the exoplanet system. Ultimately, this research has the potential to identify the source of water and other volatile materials for space exploration. I am pursuing answers to these questions through astronomical observation. My doctoral research especially focuses on asteroids via polarimetry.

Education

Publications (First author)

1. Geem, J., Ishiguro, M., Granvik, M., Naito, H., Hiroshi Akitaya, Tomohiko Sekiguchi, Sunao Hasegawa, Daisuke Kuroda, Tatsuharu Oono, Yoonsoo P. Bach, Sunho Jin, Ryo Imazawa, Koji S. Kawabata, Seiko Takagi, Makoto Yoshikawa, Anlaug A. Djupvik, Julie Thiim Gadeberg, Tapio Pursimo, Oliver Durfeldt Pedros, Jeppe Sinkbaek Thomsen, Zuri Gray. (2023). Spectral Type and Geometric Albedo of (98943) 2001 CC21, the Hayabusa2# Mission Target,, MNRAS, 525, L17–L21


2. Geem, J., Ishiguro, M., Takahashi, J., Akitaya, H., Kawabata, K., Nakaoka, T., Imazawa, R., Mori, F., Jin, S., Bach, Y., Jo, H., Kuroda, D., Hasegawa, S., Yoshida, F., Ishibashi, K., Sekiguchi, T., Beniyama, J., Arai, T., Ikeda, Y., Shinnaka, Y., Granvik, M., Siltala, L., Djupvik, A., Kasikov, A., Pinter, V., & Knudstrup, E. (2022). (3200) Phaethon polarimetry in the negative branch: new evidence for the anhydrous nature of the DESTINY target asteroid, MNRAS, 516(1), L53-L57


3. Geem, J., Ishiguro, M., Bach, Y., Kuroda, D., Naito, H., Hanayama, H., Kim, Y., Kwon, Y., Jin, S., Sekiguchi, T., Okazaki, R., Vaubaillon, J., Imai, M., Oono, T., Futamura, Y., Takagi, S., Sato, M., Kuramoto, K., & Watanabe, M. (2022). A polarimetric study of asteroids in comet-like orbits, A&A, 658, A158.

Publications (Co-author)

1. Bach, Y., Ishiguro, M., Takahashi, J., Geem. J., Kuroda, D., Naito, H., Kwon, J. (2024). Quantitative grain size estimation on airless bodies from the negative polarization branch. II. Dawn mission targets (4) Vesta and (1) Ceres, A&A, accepted.


2. Bach, Y., Ishiguro, M., Takahashi, J., Geem. J., Kuroda, D., Naito, H., Kwon, J. (2024). Quantitative grain size estimation on airless bodies from the negative polarization branch. I. Insights from experiments and lunar observations, A&A, accepted.


3. Beniyama, J., Sekiguchi, T., Kuroda, D., Arai, T., Ishibashi, K., Ishiguro, M., Yoshida, F., Senshu, H., Ootsubo, T., Sako, S., Ohsawa, R., Takita, S., Geem, J., & Bach, Y. (2023). Simultaneous multicolor photometry of the DESTINYtarget asteroid (3200) Phaethon. PASJ. 75(2), 297-310.


4. Ishiguro, M., Bach, Y., Geem, J., Naito, H., Kuroda, D., Im, M., Lee, M., Seo, J., Jin, S., Kwon, Y., Oono, T., Takagi, S., Sato, M., Kuramoto, K., Ito, T., Hasegawa, S., Yoshida, F., Arai, T., Akitaya, H., Sekiguchi, T., Okazaki, R., Imai, M., Ohtsuka, K., Watanabe, M., Takahashi, J., Devogele, M., Fedorets, G., Siltala, L., & Granvik, M. (2022). Polarimetric properties of the near-Sun asteroid (155140) 2005 UD in comparison with other asteroids and meteoritic samples. MNRAS, 509(3), 4128-4142.


5. Hasegawa, S., DeMeo, F., Marsset, M., Hanuš, J., Avdellidou, C., Delbo, M., Bus, S., Hanayama, H., Horiuchi, T., Takir, D., Jehin, E., Ferrais, M., Geem, J., Im, M., Seo, J., Bach, Y., Jin, S., Ishiguro, M., Kuroda, D., Binzel, R., Nakamura, A., Yang, B., & Vernazza, P. (2022). Spectral Evolution of Dark Asteroid Surfaces Induced by Space Weathering over a Decade. Astrophys. J., 939(1), L9. Bach, Y., Ishiguro, M., Takahashi, J., & Geem, J. (2022). Data Reduction Process and Pipeline for the NIC Polarimetry Mode in Python, NICpolpy. Stars and Galaxies, 5, 4.


6. Hasegawa, S., Marsset, M., DeMeo, F., Bus, S., Geem, J., Ishiguro, M., Im, M., Kuroda, D., & Vernazza, P. (2021). Discovery of Two TNO-like Bodies in the Asteroid Belt. Astrophys. J., 916(1), L6. Kuroda, D., Geem, J., Akitaya, H., Jin, S., Takahashi, J., Takahashi, K., Naito, H., Makino, K., Sekiguchi, T., Bach, Y., Seo, J., Sato, S., Sasago, H., Kawabata, K., Kawakami, A., Tozuka, M., Watanabe, M., Takagi, S., Kuramoto, K., Yoshikawa, M., Hasegawa, S., & Ishiguro, M. (2021). Implications of High Polarization Degree for the Surface State of Ryugu. Astrophys. J., 911(2), L24.


7. Ishiguro, M., Kuroda, D., Watanabe, M., Bach, Y., Geem. J., Lee, M., Sekiguchi, T., Naito, H., Ohtsuka, K., Hanayama, H., Hasegawa, S., Usui, F., Urakawa, S., Imai, M., Sato, M., & Kuramoto, K. (2017). Polarimetric Study of Near-Earth Asteroid (1566) Icarus. AJ, 154(5), 180.

Achievements and Awards

Academic services

2023 Journal Review, MNRAS

Presentation in Conference (or workshop, seminar)

Skills

Programming: Mainly use Python (visit my Github), Experience with C++

Driving: Achieve a driving license on 2012

Observing or Data analysis experience

* P, O, and D mean participation in Proposal, Observation, and Data analysis, respectively.

# Polarimetry

• Hokkaido Observatory, Japan (P, O, D)
  • 1.6 m Pirka telescope/MSI (Telescope/Instrument)
  • ~100 nights, ~60 targets, >10,000 data images
  • Ishiguro et al. 2017, Ishiguro et al. 2022, Geem et al. 2022a, Geem et al. 2023, Geem et al. in prep.
• Observatorio del Roque de los Muchachos, Spain (P, D)
  • 2.56 m Nordic Optical telescope/ FAPOL
  • ~20 nights, three targets
  • Ishiguro et al. 2022, Geem et al. 2022b, Geem et al. 2023
• Nishi-Harima Astronomical Observatory, Japan (P, O, D)
  • 2 m Nayuta telescope, WFGS2
  • 6 nights, four targets
  • Geem et al. 2022b, Geem et al. in prep.

# Spectroscopy

• Mauna Kea Observatory, Hawaii (P, O, D)
  • 3 m NASA IRTF, SPEX
  • PI of the proposal
  • Low-resolution, 0.7-2.5 μm
  • Two nights, one target
  • Geem et al. 2023
• Seoul National University Optical Observatory, South Korea (P, O, D)
  • 1 m telescope, LISA, 0.4-0.9 μm
  • Two targets, 5 nights
  • Hasegawa et al. 2021

# Photometry

• Ishigakijima Astronomical Observatory, Japan (D)
  • 105 cm Murikabashi telescope/MITsuME
  • g, Rc, Ic-band
  • Geem et al. 2022a
• Okayama Astrophysical Observatory, Japan (D)
  • 50 cm tel./Alta U6
  • g, Rc, Ic-band
  • Geem et al. 2022a
• Observatoire de Haute-Provence, France (D)
  • 2 m tel/Andor Ikon L 936 Camera
  • Rc-band
  • Geem et al. 2022a