Cometary Science Newsletter

November 2023
Michael S. P. Kelley (

Refereed Articles

Abstracts of articles in press or recently published. Limited to 3000 characters.

Long-lasting activity of asteroid (248370) 2005 QN173

  • Ivanova, O. 1,2,3
  • Licandro, J. 4,5
  • Moreno, F. 6
  • Luk’yanyk, I. 3
  • Markkanen, J. 7,8
  • Tomko, D. 1
  • Husárik, M. 1
  • Cabrera-Lavers, A. 9,4,5
  • Popescu, M. 10,11
  • Shablovinskaya, E. 12
  • Shubina, O. 1,2
  1. Astronomical Institute of the Slovak Academy of Sciences, Slovak Republic
  2. Main Astronomical Observatory of National Academy of Sciences of Ukraine, Ukraine
  3. Astronomical Observatory of Taras Shevchenko National University of Kyiv, Ukraine
  4. Instituto de Astrofisica de Canarias, Research, Spain
  5. Departamento de Astrofisica, Spain
  6. Instituto de Astrofísica de Andalucía, CSIC, Glorieta de la Astronomía s/n, Spain
  7. Institut fur Geophysik und Extraterrestrische Physik, Germany
  8. Max Planck Institute for Solar System Research, Germany
  9. GRANTECAN, Cuesta de San Jose s/n, Spain
  10. Astronomical Institute of the Romanian Academy, Romania
  11. A Faculty of Physics, University of Bucharest, Romania
  12. Nucleo de Astronoma de la Facultad de Ingeniera, Chile

We present the results of observations of asteroid (248370) QN173 obtained during July 2021 – January 2022 with three telescopes. Our analysis revealed the presence of the dust tail for about half of a year. The direct images of the asteroid were obtained with broad-band filters. No emissions were revealed in the spectra, and the spectrum of the asteroid closely matched that of a C-type asteroid. Created color and linear polarization variations along the tail were analyzed. The asteroid demonstrated a redder color compared to the Sun. Dramatic changes in dust productivity obtained in different filters were not detected. The g-r color changes from 0.2 mag to 0.7 mag over the coma, and the linear polarization degree varies from about 1.2% to 0.2% and from -0.2% to -1.5% at the phase angle of 23.2 deg and 8.16 deg. The total dust mass ejected until the latest observation on October 10 is 4.2 x 10^7 kg, with a maximum rate of 2.6 kg/s based on the Monte Carlo modeling of the dust tail. The estimated asteroid size is 1.3 km. It is shown that large particles are concentrated around the nucleus, whereas smaller ones dominate in the tail. The evolution of (248370) QN173 orbit and the orbits of the sample of the 464 short-periodic comets were followed. Ten of them approached the asteroid’s orbit. These objects are not genetically related, despite the very close distance of their orbits for a relatively long time.

MNRAS (Published)

DOI: 10.1093/mnras/stad2294

Palomar discovery and initial characterization of naked-eye long-period comet C/2022 E3 (ZTF)

  • B T Bolin 1,2,3
  • F J Masci 2,3
  • D A Duev 4
  • J W Milburn 5
  • J D Neill 2,5
  • J N Purdum 5
  • C Avdellidou 6,7
  • M Saki 8,9
  • Y-C Cheng 10
  • M Delbo 6
  • C Fremling 2,5
  • M Ghosal 11
  • Z-Y Lin 12
  • C M Lisse 13
  • A Mahabal2
  1. NASA, Goddard Space Flight Center, USA
  2. Caltech Astronomy, USA
  3. IPAC, USA
  4. Weights and Biases, USA
  5. Caltech Optical Observatories, USA
  6. Observatoire de la Côte d'Azur
  7. School of Physics and Astronomy, University of Leicester, UK
  8. Dept. of Physics, Auburn University, USA
  9. Dept. of Mathematics, Physics, Astronomy, & Statistics, University of Missouri, USA
  10. Dept. of Physics, National Taiwan Normal University, Taiwan
  11. Institute for Astronomy, University of Hawaii, USA
  12. Institute of Astronomy, National Central University, Taiwan
  13. Johns Hopkins University Applied Physics Laboratory, USA

Long-period comets are planetesimal remnants constraining the environment and volatiles of the protoplanetary disc. We report the discovery of hyperbolic long-period comet C/2022 E3 Zwicky Transient Facility (ZTF), which has a perihelion ∼1.11 au, an eccentricity ≳1 and an inclination ∼109°, from images taken with the Palomar 48-inch telescope during morning twilight on 2022 March 2. Additionally, we report the characterization of C/2022 E3 (ZTF) from observations taken with the Palomar 200-inch, the Palomar 60-inch, and the NASA Infrared Telescope Facility in early 2023 February to 2023 March when the comet passed within ∼0.28 au of the Earth and reached a visible magnitude of ∼5. We measure g–r = 0.70 ± 0.01, r–i = 0.20 ± 0.01, i–z = 0.06 ± 0.01, z–J = 0.90 ± 0.01, J–H = 0.38 ± 0.01, and H–K = 0.15 ± 0.01 colours for the comet from observations. We measure the A(0°)fρ (0.8 μm) in a 6500 km radius from the nucleus of 1483 ± 40 cm, and CN, C3, and C2 production of 5.43 ± 0.11 × 10^25, 2.01 ± 0.04 × 10^24, and 3.08 ± 0.5 × 10^25 mol s−1, similar to other long-period comets. We additionally observe the appearance of jet-like structures at a scale of ∼4000 km in wide-field g-band images, which may be caused by the presence of CN gas in the near-nucleus coma.

Monthly Notices of the Royal Astronomical Societ (Published)

DOI: 10.1093/mnrasl/slad139 NASA ADS: 2024MNRAS.527L..42B arXiv: 2309.14336

The Wagging Plasma Tail of Comet C/2020 S3 (Erasmus)

  • Li, Jing 1
  • Kim, Yoonyoung 1
  • Jewitt, David 1
  1. Department of Earth, Planetary and Space Sciences, University of California, Los Angeles, CA 90095, USA

Long-period comet C/2020 S3 (Erasmus) reached perihelion at 0.398 au on UT 2020 December 12.67, making it a bright, near-Sun object. Images taken between mid-November and December 2020 using the HI-1 camera and COR2 coronagraph onboard STEREO-A, as well as the LASCO/C3 coronagraph onboard SoHO, show significant variations in the plasma tail position angles. To analyze these variations, a simple technique was developed to calculate the aberration angles. These angles are defined as the angle between the sun-comet line and the tail axis, measured in the orbital plane. The aberration angles were found to range from 1.2 deg to 46.8 deg, with an average (median) value of approximately 20.3 deg (16.3 deg). By considering the aberration angles, the solar wind radial velocities during the observations were inferred to range from 73.9 km/s to 573.5 km/s, with mean (median) values of approximately 205.5 km/s (182.3 km/s). Throughout the observations, two periods were identified where the tails showed forward tilting, which cannot be explained by aberration alone. In one case, this anomalous position angle was sustained for at least 11 days and is possibly due to co-rotating interaction regions. In the other case, the tail exhibited dramatic excursions from 180 deg to 150 deg back to 210 deg over a limited period of around 34 hours. This behavior is tentatively explained as a consequence of the interaction with a halo Coronal Mass Ejection that was launched from NOAA 12786 and arrived at comet C/2020 S3 during the time when the tail displayed its wagging behavior.

Astronomical Journal (In press)

NASA ADS: 2023arXiv231016219L arXiv: 2310.16219