< Stars‎ | Flares
This is a TRACE image of the coronal arcade structure in the flare on Bastille Day, 1998. Credit: NASA.

Flare stars is a lecture about an entity, source, and/or object observed on or near the surface of a star with radiation astronomy.

It may become part of the course on the principles of radiation astronomy and is already part of the star courses.

You are free to take this quiz is based on the lecture flare stars at any time.

Once you've read and studied it, the links contained within, listed under See also, External links, and in the {{stars resources}} and {{radiation astronomy resources}} templates, you should have adequate background to score 100 %.

Suggestion: Have the lecture available in a separate window.

Enjoy learning by doing!



1 Which of the following are radiation astronomy phenomena associated with the Sun?

ultraviolet emission
X-ray emission
gamma-ray emission
neutron emission
7Be emission
meteor emission

2 Which of the following is not a characteristic of solar active regions?

coronal clouds
spot central meridian passage
a surface coverage of at least 95%.

3 During the late 1600s the sunspot cycle lost its usual intensity and became what?

4 True or False, Naked sunspots seen in Hα which are devoid of plage are never associated with coronal holes.


5 Complete the text:



originate in magnetically

around visible


6 True or False, A spicule is a dynamic jet of about 500 km diameter in the chromosphere of a star.


7 When faculae are present, what characteristics are readily observed?

bright spots
bright patches
magnetic poles
arising in the photosphere
neon clouds

8 The population of coronal loops can be directly linked with the?

9 True or False, Coronal loops project into the coronal cloud, through the transition region and the chromosphere.


10 Which of the following is not a prominent contributor associated with a variable star?

star spots
chromospheric activity
brightness fluctuations
spot coverage fraction

11 In general there is no proper motion at all in the plage or the surrounding?

12 True or False, Some prominences break apart and give rise to coronal mass ejections.


13 Complete the text:

"When a prominence is viewed from a different perspective so that it is against the

instead of against space, it appears

than the surrounding


14 Which of the following active region phenomena have been observed on Proxima Centauri?

temperatures as high as 27 MK
quiescent X-ray luminosity comparable to the Sun
a surface coverage of about 88%
likely prominence

15 Active regions are the result of enhanced what?

16 True or False, Most stellar flares and coronal mass ejections originate in magnetically inactive regions around visible sunspot groupings.


17 Which of the following are associated with the stellar active region control group?

solar cycle
closed magnetic structures
solar wind
long-lived loop arcades
helmet streamers
the Sun

18 A super flare on the evening of August 28, 1859, was recorded by

19 Which of the following are characteristic of the first true astrophysical gamma-ray source?

a strong 2.223 MeV emission line
a solar flare
the formation of deuterium
the electron neutrino

20 True or False, "75% of the naked sunspots represented the return of large dominant f spots which had been part of large active regions during previous rotations."


21 Which geographical phenomena are associated with stellar active regions?

moving across the surface of the Sun or star
manifesting intense magnetic fields
a north geographic and magnetic pole
a prime meridian
average starspot latitudes
the solar or stellar equator

22 Coronal loops extend high into the corona, project through the chromosphere, and project through what above the photosphere?

23 True or False, Coronal loops populate both active and quiet regions of the solar surface.


24 Phenomena associated with nanoflares?

1017 Joules
very high X-ray emission from happening every 20 s
mass eruptions
active regions

25 Main sequence variable stars of late spectral types, usually K or M, exhibiting variations in luminosity due to rotation, starspots and other chromospheric activity are called?

26 The type star that goes through fairly extreme changes of brightness: for instance, in 1952, its brightness increased by 75 times in only 20 seconds, is what star?

27 About one third of solar ejecta observed by satellites at Earth is composed of what?

28 True or False, A spotless flare may occur in a plage region during its first rotation.


29 Which stars of the alpha Centauri system are known to have flares?

Proxima Centauri
Alpha Centauri B
Barnard's star
Alpha Centauri A
Rigel Kent
Alpha Centauri C
Alpha Centauri D


  1. Apparently the active region cycle for the Sun corresponds to the repeated conjunction of Venus and Jupiter.

See alsoEdit

External linksEdit

{{Radiation astronomy resources}}