Letter to the Editor
The infant bow shock: a new frontier at a weak activity comet
1 Royal Belgian Institute for Space Aeronomy (BIRA-IASB), Avenue Circulaire 3, 1180 Brussels, Belgium
e-mail: herbert.gunell@physics.org
2 Department of Physics, Umeå University, 901 87 Umeå, Sweden
3 Institut für Geophysik und extraterrestrische Physik, TU Braunschweig, Mendelssohnstr. 3, 38106 Braunschweig, Germany
e-mail: c.goetz@tu-bs.de
4 Department of Physics, University of Oslo, Box 1048 Blindern, 0316 Oslo, Norway
5 Swedish Institute of Space Physics, Box 812, 981 28 Kiruna, Sweden
6 Southwest Research Institute, 6220 Culebra Rd., San Antonio, TX 78238, USA
7 Swedish Institute of Space Physics, Ångström Laboratory, Lägerhyddsvägen 1, 751 21 Uppsala, Sweden
Received:
12
September
2018
Accepted:
15
October
2018
The bow shock is the first boundary the solar wind encounters as it approaches planets or comets. The Rosetta spacecraft was able to observe the formation of a bow shock by following comet 67P/Churyumov–Gerasimenko toward the Sun, through perihelion, and back outward again. The spacecraft crossed the newly formed bow shock several times during two periods a few months before and after perihelion; it observed an increase in magnetic field magnitude and oscillation amplitude, electron and proton heating at the shock, and the diminution of the solar wind further downstream. Rosetta observed a cometary bow shock in its infancy, a stage in its development not previously accessible to in situ measurements at comets and planets.
Key words: comets: general / comets: individual: 67P/Churyumov / Gerasimenko / plasmas / shock waves
© ESO 2018