Mira (Omicron Ceti)

Mira is a:

• White dwarf

• Red giant variable star

• Neutron star

• Black hole

Answer explanation

Mira is classified as a red giant variable star, known for its significant brightness variations. This distinguishes it from other types like white dwarfs, neutron stars, and black holes, which have different characteristics.

What type of variable star is Mira classified as?

• Cepheid variable

• RR Lyrae variable

• Mira-type long-period variable

• Wolf-Rayet star

Answer explanation

Mira is classified as a Mira-type long-period variable star due to its significant brightness variations over a period of about 331 days, distinguishing it from Cepheid and RR Lyrae variables.

The name 'Mira' comes from the Latin word meaning:

• Brightest

• Wonderful

• Swift

• Everlasting

Answer explanation

The name 'Mira' is derived from the Latin word 'mirabilis', which means 'wonderful'. This makes 'Wonderful' the correct choice among the options provided.

Mira was first identified as a variable star in:

• 134 BC by Hipparchus

• 1596 by David Fabricius

• 1781 by William Herschel

• 1924 by Edwin Hubble

Answer explanation

Mira was first identified as a variable star in 1596 by David Fabricius, who observed its changing brightness. The other dates and individuals listed are not associated with Mira's identification.

Which constellation is Mira located in?

• Orion

• Andromeda

• Cetus

• Lyra

Answer explanation

Mira, also known as Omicron Ceti, is located in the constellation Cetus. It is a red giant star and one of the brightest stars in this constellation, making Cetus the correct answer.

The primary component of the Mira system, Mira A, is currently in what stage of stellar evolution?

• Main-sequence star

• Red giant phase

• Supernova remnant

• White dwarf

Answer explanation

Mira A is currently in the red giant phase, which occurs after a star has exhausted hydrogen in its core and expanded significantly. This phase is characterized by a cooler surface temperature and increased luminosity.

What is the approximate variability period of Mira?

• 11 days

• 88 days

• 332 days

• 1460 days

Answer explanation

Mira, a red giant star, has a variability period of approximately 332 days. This means it undergoes changes in brightness over this time frame, making 332 days the correct choice among the options provided.

What causes the brightness variations in Mira-type stars?

• Eclipses by a companion star

• Pulsations in the star’s outer layers

• Changes in its magnetic field

• Accretion of material from another star

Answer explanation

The brightness variations in Mira-type stars are primarily caused by pulsations in the star’s outer layers, leading to changes in size and temperature, which affect their luminosity.

Mira’s brightness can change by a factor of:

• 2

• 5

• 100

• 1,000

Answer explanation

Mira's brightness can change significantly, with a maximum factor of 1,000. This means it can become 1,000 times brighter or dimmer, making '1,000' the correct choice among the options.

Mira is often used as a prototype for:

• Cepheid variables

• Eclipsing binaries

• Long-period variable stars

• Neutron star mergers

Answer explanation

Mira is a well-known example of a long-period variable star, specifically a Mira-type variable. Its brightness varies significantly over a period of about 11 months, making it a prototype for this category of stars.