The first coronal mass ejection observed in both visible-light and UV H I Ly-α channels of the Metis coronagraph on board Solar Orbiter
Articolo
Data di Pubblicazione:
2021
Abstract:
Context. The Metis coronagraph on board Solar Orbiter oers a new view of coronal mass ejections (CMEs), observing them for the first time
with simultaneous images acquired with a broad-band filter in the visible-light interval and with a narrow-band filter around the Hi Ly- line at
121.567 nm, the so-called Metis UV channel.
Aims. We show the first Metis observations of a CME, obtained on 16 and 17 January 2021. The event was also observed by the EUI/FSI imager
on board Solar Orbiter, as well as by other space-based coronagraphs, such as STEREO-A/COR2 and SOHO/LASCO/C2, whose images are
combined here with Metis data.
Methods. Dierent images are analysed here to reconstruct the 3D orientation of the expanding CME flux rope using the graduated cylindrical
shell model. This also allows us to identify the possible location of the source region. Measurements of the CME kinematics allow us to quantify
the expected Doppler dimming in the Ly- channel.
Results. Observations show that most CME features seen in the visible-light images are also seen in the Ly- images, although some features
in the latter channel appear more structured than their visible-light counterparts. We estimated the expansion velocity of this event to be below
140 km s1. Hence, these observations can be understood by assuming that Doppler dimming eects do not strongly reduce the Ly- emission
from the CME. These velocities are comparable with or smaller than the radial velocities inferred from the same data in a similar coronal structure
on the east side of the Sun.
Conclusions. The first observations by Metis of a CME demonstrate the capability of the instrument to provide valuable and novel information on
the structure and dynamics of these coronal events. Considering also its diagnostics capabilities regarding the conditions of the ambient corona,
Metis promises to significantly advance our knowledge of such phenomena.
with simultaneous images acquired with a broad-band filter in the visible-light interval and with a narrow-band filter around the Hi Ly- line at
121.567 nm, the so-called Metis UV channel.
Aims. We show the first Metis observations of a CME, obtained on 16 and 17 January 2021. The event was also observed by the EUI/FSI imager
on board Solar Orbiter, as well as by other space-based coronagraphs, such as STEREO-A/COR2 and SOHO/LASCO/C2, whose images are
combined here with Metis data.
Methods. Dierent images are analysed here to reconstruct the 3D orientation of the expanding CME flux rope using the graduated cylindrical
shell model. This also allows us to identify the possible location of the source region. Measurements of the CME kinematics allow us to quantify
the expected Doppler dimming in the Ly- channel.
Results. Observations show that most CME features seen in the visible-light images are also seen in the Ly- images, although some features
in the latter channel appear more structured than their visible-light counterparts. We estimated the expansion velocity of this event to be below
140 km s1. Hence, these observations can be understood by assuming that Doppler dimming eects do not strongly reduce the Ly- emission
from the CME. These velocities are comparable with or smaller than the radial velocities inferred from the same data in a similar coronal structure
on the east side of the Sun.
Conclusions. The first observations by Metis of a CME demonstrate the capability of the instrument to provide valuable and novel information on
the structure and dynamics of these coronal events. Considering also its diagnostics capabilities regarding the conditions of the ambient corona,
Metis promises to significantly advance our knowledge of such phenomena.
Tipologia CRIS:
01.01 - Articolo in rivista
Keywords:
Sun: atmosphere – Sun: corona – Sun: UV radiation – Sun: coronal mass ejections (CMEs)
Elenco autori:
Andretta, V.; Bemporad, A.; De Leo, Y.; Jerse, G.; Landini, F.; Mierla, M.; Naletto, G.; Romoli, M.; Sasso, C.; Slemer, A.; Spadaro, D.; Susino, R.; Talpeanu, D. -C.; Telloni, D.; Teriaca, L.; Uslenghi, M.; Antonucci, E.; Auchère, F.; Berghmans, D.; Berlicki, A.; Capobianco, G.; Capuano, G. E.; Casini, C.; Casti, M.; Chioetto, P.; Da Deppo, V.; Fabi, M.; Fineschi, S.; Frassati, F.; Frassetto, F.; Giordano, S.; Grimani, C.; Heinzel, P.; Liberatore, A.; Magli, E.; Massone, G.; Messerotti, M.; Moses, D.; Nicolini, G.; Pancrazzi, M.; Pelizzo, M. -G.; Romano, P.; Schühle, U.; Stangalini, M.; Straus, Th.; Volpicelli, C. A.; Zangrilli, L.; Zuppella, P.; Abbo, L.; Aznar Cuadrado, R.; Bruno, R.; Ciaravella, A.; D’Amicis, R.; Lamy, P.; Lanzafame, A.; Malvezzi, A. M.; Nicolosi, P.; Nisticò, G.; Peter, H.; Plainaki, C.; Poletto, L.; Reale, F.; Solanki, S. K.; Strachan, L.; Tondello, G.; Tsinganos, K.; Velli, M.; Ventura, R.; Vial, J. -C.; Woch, J.; Zimbardo, G.
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