The first coronal mass ejection observed in both visible-light and UV H I Ly-alpha channels of the Metis coronagraph on board Solar Orbiter

0552536 - ASÚ 2022 RIV FR eng J - Journal Article
Andretta, V. - Bemporad, A. - De Leo, Y. - Heinzel, Petr … Total 71 authors
The first coronal mass ejection observed in both visible-light and UV H I Ly-alpha channels of the Metis coronagraph on board Solar Orbiter.
Astronomy & Astrophysics. Roč. 656, December (2021), č. článku L14. ISSN 0004-6361. E-ISSN 1432-0746
Institutional support: RVO:67985815
Keywords : Sun * atmosphere * corona
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 6.240, year: 2021
Method of publishing: Open access with time embargo
https://doi.org/10.1051/0004-6361/202142407

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. Different 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-alpha channel. Observations show that most CME features seen in the visible-light images are also seen in the Ly-alpha 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 s(-1). Hence, these observations can be understood by assuming that Doppler dimming effects do not strongly reduce the Ly-alpha 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.
Permanent Link: http://hdl.handle.net/11104/0327646