Stars/Flares/Quiz - Wikiversity

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 %.

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Enjoy learning by doing!

1 Quiz
2 Hypotheses
3 See also
4 External links

Quiz

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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?

	lithium
	nucleosynthesis
	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.

	TRUE
	FALSE

5 Complete the text:

Most

and

originate in magnetically

around visible

groupings.

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

	TRUE
	FALSE

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

	bright spots
	bright patches
	starspots
	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.

	TRUE
	FALSE

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

	star spots
	chromospheric activity
	rotation
	brightness fluctuations
	flares
	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.

	TRUE
	FALSE

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?

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

	TRUE
	FALSE

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
	OSO-3
	neutrons

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."

	TRUE
	FALSE

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
	rotation
	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.

	TRUE
	FALSE

24 Phenomena associated with nanoflares?

	10¹⁷ Joules
	very high X-ray emission from happening every 20 s
	flickerings
	brightenings
	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.

	TRUE
	FALSE

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

Hypotheses

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Main resource: Hypotheses

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

External links

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NASA/IPAC Extragalactic Database - NED
The SAO/NASA Astrophysics Data System
SIMBAD Astronomical Database

Learn more about Flare stars