The Science of Near-Sun Comets

ISSI International Team

The Science of Near-Sun Comets

Image: SOHO LASCO and EIT teams, image created using Helioviewer

Summary

Our knowledge of comets is primarily based on observations of these bodies when they are one astronomical unit or more from the Sun. However, most known comets have reached perihelion much nearer to the Sun, experiencing extreme insolation conditions, and, in the case of sungrazers, often undergoing complete destruction. Our ISSI International Team brings together experts in complementary areas of cometary science, in solar and heliospheric physics, as well as in the instrumentation and data analysis techniques associated with those fields, to better our understanding of comets when inside the orbit of Mercury as well as their effects on the near-Sun environment.

The team's overall aims are to:

(1) Produce a comprehensive review paper on near-Sun comets

(2) Further exploit data sources to address these five topics:

    Dust tails
    Ion tails
    Coma chemistry
    Neutral gas tails
    Temporal behaviour

Team Members

Karl Battams, Naval Research Laboratory, Washington, D. C., USA
Daniel Boice, Southwest Research Institute, San Antonio, USA
John Brown, University of Glasgow, UK
Maciej Bzowski, CBK, Poland
Alan Fitzsimmons, Queens University Belfast, UK
Silvio Giordano, INAF, Italy
Geraint Jones, Mullard Space Science Laboratory, University College London, UK (organizer)
Matthew Knight, Lowell Observatory, Flagstaff, USA
Carey Lisse, Johns Hopkins University Applied Physics Laboratory, USA
John Raymond, Harvard-Smithsonian Center for Astrophysics, USA
Colin Snodgrass, Max Planck Institute for Solar System Research, Germany
Paul Weissman, Jet Propulsion Laboratory, Pasadena, USA
Ingrid Mann, EISCAT Scientific Association, Sweden

Young Scientist Team Members

Kimberley Birkett, University College London, UK
Alice Decock, University of Liège, Belgium
Patrick McCauley, Harvard-Smithsonian Center for Astrophysics, USA
Yudish Ramanjooloo, University College London, UK
Cyrielle Opitom, University of Liège, Belgium
Jordan Steckloff, Purdue University, USA

Second Meeting

The team's second meeting will take place at ISSI, Bern, during March 23-27, 2015.

Timetable:

Monday, March 23	11:00-13:15 14:30-17:00	Opening Session Welcome (Jones) Overview of week's activities, initial plans (Jones) Brief update on review paper progress Introductory Talks I Weissman: The Rosetta Mission Knight & Battams: C/2015 D1 (SOHO) - A recent near-Sun comet. Battams: The orbit of Comet ISON - non-gravitational effects at perihelion Steckloff: Gas Leaks are Dangerous!!! How sublimating volatiles can push around, break up, and striate comets
Tuesday, March 24	09:30-13:00 14:30-17:30	Introductory Talks II Fitzsimmons, Snodgrass, & Knight: Sungrazer observation prospects from ground-based observatories. Raymond: Exocomets as they relate to sungrazers Raymond & Giordano: Solar Orbiter Ly-alpha imaging of comets in the solar corona Birkett: Sodium tail modelling Opitom: Trappist monitoring of comet C/2012 S1(ISON) Boice: Physics and Chemistry of Near-Sun Comets II Brown: 1. Sun-plunging (low chromosphere) comet destruction (work with Bob Carlson) 2. Sun-skimmer (low corona) mass, momentum and energy loss and mechanisms of tail heating and ionisation Review Paper Writing Session I
Wednesday, March 25	09:30-17:30	General Discussions and split into collaborative sub-groups as required Free morning or afternoon? (TBC)
Thursday, March 26	09:30-17:30	Review Paper Writing Session II Collaborative sub-groups II
Friday, March 27	09:30-14:00	Closing Session Review of progress. Final plans for review paper completion and submission. Plans for continued collaboration and publications. Discussion on date and locations of joint conference presentations, and potential sub-meetings at relevant conferences. End of Meeting

First Meeting

The team's first meeting took place at ISSI, Bern, during March 3-7, 2014.

Timetable:

Monday, March 3	11:00-13:15 14:30-17:00	Opening Session Welcome (Jones) Introduction to ISSI (Falanga) Overview of week's activities, initial plans (Jones) Introductory Talks I Knight: Near-Sun Comets: What we know and what we'd like to know Battams: Near-Sun Comet Observations from SOHO-LASCO and STEREO-SECCHI Giordano: UVCS Observations of Sungrazing Comets Raymond, McCauley: EUV and X-Ray Observations of Comet C/2011 W3 (Lovejoy) in the Lower Corona
Tuesday, March 4	09:30-13:00 14:30-17:30	Introductory Talks II Weissman: Tidal Disruption of Rubble-Pile Nuclei in Sun-Grazing Orbits Brown: Comet interaction regimes in the inner solar atmosphere Boice: Coma Chemistry in the Near-Sun Environment Decock: The forbidden oxygen lines in a large sample of cometary spectra Birkett: Sodium Tails Snodgrass: Ground-based observations of Near-Sun Comets Jones, Ramanjooloo: Ion Tails of Near-Sun Comets
Wednesday, March 5	09:30-17:30 Evening	Plans for review paper General Discussions I Including: - physics of comet-Sun interactions (Brown) - full exploitation of solar datasets Team Dinner
Thursday, March 6	09:30-17:30	General Discussions II Including extended discussion on possible crossing of dust tail of C/2004 F4 (Bradfield)
Friday, March 7	09:30-14:00	Closing Session Review of progress Plans for continued collaboration and publications. Discussion on date of next meeting, aims, and potential sub-meetings at relevant conferences. (Jones) End of Meeting

Questions? Please contact Geraint Jones