Cometary Science Newsletter

July 2019
Michael S. P. Kelley (

ESA Research Fellowships in Space Science

The European Space Agency awards several postdoctoral fellowships each year.

The aim of these fellowships is to provide scientists in their early career, holding a PhD or the equivalent degree, with the means of performing research in fields related to the ESA Science Programme.

Areas of research include planetary science, astronomy and astrophysics, solar and solar-terrestrial science, plasma physics and fundamental physics. The fellowships have a duration of two years, with the possible extension to three years, and are tenable at the European Space Research and Technology Centre (ESTEC) in Noordwijk, Netherlands, or at the European Space Astronomy Centre (ESAC) in Villafranca del Castillo, near Madrid, Spain.

Applications are now solicited for fellowships in space science to begin in the fall of 2020. Preference will be given to applications submitted by candidates in an early stage of their career. Candidates not holding a PhD yet are encouraged to apply, but they must provide evidence of receiving their degree before starting the fellowship.

ESA fellows are enrolled in ESA's Social Security Scheme, which covers medical expenses. A monthly deduction covers these short-term and long-term risks.

The deadline for applications is 1 October 2019.

More information on the ESA Research Fellowship programme in Space Science, on the conditions and eligibility, as well as the application form can retrieved from

Questions on the scientific aspects of the ESA Fellowship in Space Science not answered in the above pages can be sent by e-mail to the fellowship coordinators, Dr. Oliver Jennrich or Dr. Jan-Uwe Ness at the address

ESA selects Comet Interceptor as its first 'fast' mission

The European Space Agency has announced that its first F-class ('fast') mission will be Comet Interceptor, which will encounter a yet-to-be-discovered dynamically new comet. It is scheduled to launch in 2028 as a secondary payload with the Ariel space telescope, which it will accompany to an orbit around the Sun-Earth L2 point, where it will wait for a suitable target for up to a few years. Once a target comet is identified the spacecraft will depart from L2 to perform a fast fly-by, releasing two smaller probes just prior to the encounter to obtain multi-point measurements in the coma. For more details see .

Geraint Jones and Colin Snodgrass, on behalf of the Comet Interceptor team.

Postdoctoral Research Associate in Planetary Sciences

The Small Bodies Group in the Department of Astronomy at the University of Maryland, College Park invites applications for a Postdoctoral Research Associate to work with Dr. Tony Farnham and Dr. Jessica Sunshine to develop and apply models to simulate sublimation processes on solar system bodies, to explore how they impact the surface features and morphology, and to intercompare results among different objects. Of particular interest in this study are bodies with microgravity environments, including the Rosetta target comet 67P/Churyumov-Gerasimenko.

Candidates for this position should have a Ph.D. in Physics, Astronomy, Planetary Science or a related field, which must be obtained by the time of the start date. IDL or similar experience is preferred. This appointment will be for two years with a possible third year extension based on performance and funding availability.

For more information about the position and instructions on how to apply, go to

Conference Announcements

Announcements for cometary conferences or workshops. Limited to 2000 characters.

Update: New Cometary Insights from the Close Approach of 46P/Wirtanen: A Symposium in Celebration of Mike A'Hearn

Registration and abstracts:

This is a reminder that registration for the meeting (August 6-8, 2019 on the University of Maryland campus) is currently open. Early registration ends on July 12, 2018, at which time the registration fee increases from $125 to $135.

We also note that although comet Wirtanen, due to its recent close approach, was highlighted for the theme of the symposium, we invite other talks as well, including those about other comets, about big-picture views of comets, or simply talks presenting memories of Mike.

Abstracts requesting an oral talk are due on July 12. Submissions after that date are likely to be assigned poster status.

Student travel support:

We have a small amount of funding available to help support student travel. (The amount will depend on the number of valid requests we receive.) If you are interested in applying for this support, please send a 1-page application describing your student status, Institution, who you are working with, and what you intend to present. Applications are due by the July 12 registration deadline and can be emailed to

For more information about the meeting and a link to the registration site, goto to

PhD Dissertations

Abstracts of recent PhD dissertations. Limited to 3000 characters.

Optical Spectroscopic Studies of Minor Bodies of the Solar System

  • Kumar Venkataramani
  • Indian Institute of Technology, Gandhinagar, India; Physical Research Laboratory, Ahmedabad, India

The minor bodies in the solar system comprise of asteroids, comets, trans-Neptunian objects, dwarf planets, planetary satellites, the Trojans of the giant planets, Centaurs and Kuiper belt objects. Of these, comets carry a significant amount of pristine material from the early solar system and are relatively bright objects which can be observed and studied using even one meter class telescopes. Therefore this thesis work has focused on studying comets and near-Earth asteroids on comet like orbits. Optical spectroscopic studies of these objects have been carried out using the 0.5 m and 1.2 m telescopes at the Mount Abu Infra-red Observatory with an aim of contributing towards answering some of the questions in cometary and solar-system science. A plethora of emission lines are seen in the optical spectrum of a comet. These arise due to the fluorescence excitation of the various molecular and ionic species of the gases present in a comet's coma.

In this work, we have monitored the activity in different comets by spectroscopically observing them at various heliocentric distances. The low resolution spectrograph LISA has been used to obtain the optical spectra of different comets and asteroids. The optical spectra of long period comets: C/2014 Q2 (Lovejoy), C/2013 US10 (Panstarrs), C/2013 X1 (Panstarrs), C/2015 V2 (Johnson) and two short period comets: 41P/Tuttle–Giacobini–Kresák and 45P/Honda–Mrkos–Pajdušáková were obtained at different epochs. The production rates, production rate ratios, dust production and dust to gas ratio were estimated for these comets and their trends with the heliocentric distance were studied.

The comets 41P and C/2015 V2 have also been imaged using the Hale-Bopp Narrow band filters. Comet C/2016 R2 showed an unusual spectrum, quite different from the general cometary spectra. An in depth analysis of the optical spectrum of this comet has been carried out. First comet observations with the Hanle Echelle Spectrograph at the 2m Himalayan Chandra Telescope were done during the course of this work.

The near Earth asteroid 2014 JO25 was spectroscopically followed during its close flyby of Earth in April 2017. A significant range of phase angle was covered during the observations of this asteroid. Results from these observations have also been discussed.

Most of the observations have been carried out using smaller class of telescopes and a small spectrograph. This demonstrates and exemplifies the importance of small telescopes and ground based observations of minor bodies of the solar system.

Refereed Articles

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

Time and Phase Resolved Optical Spectra of Potentially Hazardous Asteroid 2014 JO25

  • Kumar Venkataramani 1,2
  • Shashikiran Ganesh 1
  • Archita Rai 1,2
  • Marek Husárik 3
  • K. S. Baliyan 1
  • U. C. Joshi 1
  1. Astronomy & Astrophysics Division, Physical Research Laboratory, Navarangpura, Ahmedabad, India.
  2. Indian Institue of Technology, Gandhinagar, India
  3. Astronomical Institute of the Slovak Academy of Sciences, SK-05960 Tatranská Lomnica, Slovakia

The asteroid 2014 JO25, considered to be potentially hazardous by the Minor Planet Center, was spectroscopically followed during its close-Earth encounter on 2017 April 19 and 20. The spectra of the asteroid were taken with the low-resolution spectrograph (LISA), mounted on the 1.2 m telescope at the Mount Abu Infrared Observatory, India. Coming from a region close to the Hungaria population of asteroids, this asteroid follows a comet-like orbit with a relatively high inclination and large eccentricity. Hence, we carried out optical spectroscopic observations of the asteroid to look for comet-like molecular emissions or outbursts. However, the asteroid showed a featureless spectrum, devoid of any comet-like features. The light curve of the asteroid was analyzed using V-band magnitudes derived from the spectra and the most likely solution for the rotation of the asteroid was obtained. The absolute magnitude H and the slope parameter G were determined for the asteroid in the V filter band using the IAU accepted standard two-parameter H–G model. A peculiar, rarely found result from these observations is its phase bluing trend. The relative B–V color index seems to decrease with increasing phase angle, which indicates a phase bluing trend. Such trends have seldom been reported in the literature. However, phase reddening in asteroids is very common. The asymmetry parameter g and the single-scattering albedo w were estimated for the asteroid by fitting the Hapke phase function to the observed data. The asteroid shows a relatively large value for the single-scattering albedo and a highly back-scattering surface.

The Astronomical Journal (Published)

DOI: 10.3847/1538-3881/ab0f26 NASA ADS: 2019AJ....157..199V arXiv: 1903.04764