What is the difference between Type 1 and Type 2 Cepheids?

What is the difference between Type 1 and Type 2 Cepheids?

There are actually two classes of Cepheid: Type I Cepheids (δ Cepheus is a classical Cepheid) are population I stars with high metallicities, and pulsation periods generally less than 10 days. Type II Cepheids (W Virginis stars), are low-metallicity, population II stars with pulsation periods between 10 and 100 days.

What is so special about Cepheids?

Cepheids Variables are special type of variable star in that they are hot and massive – five to twenty times as much mass as our Sun – and are known for their tendency to pulsate radially and vary in both diameter and temperature.

Why do Cepheids pulsate?

Pulsating variable stars are intrinsic variables as their variation in brightness is due to a physical change within the star. In the case of pulsating variables this is due to the periodic expansion and contraction of the surface layers of the stars.

What does Hubble’s law tell us?

Hubble’s law, which says simply that a galaxy’s velocity (or as is sometimes plotted, its redshift) is directly proportional to its distance, also tells us something important about the state of the universe. If the universe is static and unchanging, there should be no correlation between distance and velocity.

How many types of Cepheids exist?

Cepheid variables are divided into two subclasses which exhibit markedly different masses, ages, and evolutionary histories: classical Cepheids and type II Cepheids.

Which type of variable star has the shortest period?

EGGEN Lick Observatory, University of California As the result of observations made at the Commonwealth Observatory, Canberra, Australia, the star RD 223065 (23h 41’~2, —42° 07′, 1900) has been found to be an RR Lyrae variable with the short period of 80 minutes.

How are galactic distances determined?

Astronomers can use what are called surface brightness fluctuations (SBF, for short), along with the color of a galaxy, to calculate how far away it is from earth. Most galaxies measured in this way are millions of light years away.

What type of stars have longer periods 2 to 60 days )?

Cepheid variables have the following properties: Period = 2 to 60 days.

Which star takes longer to pulse?

star A-091 take longer to pulse than the other star.

Why are there two dips in the Lightcurve in each period?

During eclipses of either star, two sharp dips are observed in the light curve. The dips in brightness are caused by the combined areas during the eclipse or occultation, producing decreasing the total brightness. Periods of all EA types averages about 10 days, or more.

What happens during the main sequence stage?

Main sequence stars fuse hydrogen atoms to form helium atoms in their cores. About 90 percent of the stars in the universe, including the sun, are main sequence stars. These stars can range from about a tenth of the mass of the sun to up to 200 times as massive. Stars start their lives as clouds of dust and gas.

What are the 5 stages of a star?

All stars, irrespective of their size, follow the same 7 stage cycle, they start as a gas cloud and end as a star remnant.

• Giant Gas Cloud. A star originates from a large cloud of gas.
• Protostar.
• T-Tauri Phase.
• Main Sequence.
• Red Giant.
• The Fusion of Heavier Elements.
• Supernovae and Planetary Nebulae.

What does each star become after the main sequence stage?

Eventually, as stars age, they evolve away from the main sequence to become red giants or supergiants. The core of a red giant is contracting, but the outer layers are expanding as a result of hydrogen fusion in a shell outside the core. The star gets larger, redder, and more luminous as it expands and cools.

What will happen if a low massive main sequence?

Answer. Answer: low mass stars are: hydrogen burning in the core while on the Main Sequence. as the hydrogen fuel runs out, extreme pressure raises the temperature to 100 million degrees, where helium burning becomes possible.

What does the main sequence represent?

The great majority are aligned along a narrow sequence running from the upper left (hot, highly luminous) to the lower right (cool, less luminous). This band of points is called the main sequence. It represents a relationship between temperature and luminosity that is followed by most stars.

What are the six stages of a star?

Formation of Stars Like the Sun

• STAGE 1: AN INTERSTELLAR CLOUD.
• STAGE 2: A COLLAPSING CLOUD FRAGMENT.
• STAGE 3: FRAGMENTATION CEASES.
• STAGE 4: A PROTOSTAR.
• STAGE 5: PROTOSTELLAR EVOLUTION.
• STAGE 6: A NEWBORN STAR.
• STAGE 7: THE MAIN SEQUENCE AT LAST.

What color of star is the hottest?

Blue stars

What happens after a star forms?

All the material that has fallen in then evolves into a hot, bright star. The star will continue to shine as long as there is hydrogen gas to fuse through nuclear reactions, and the gravitational pressure pushing inward keeps the atoms very hot and tightly packed at the center.

What is a dying star called?

supernovae

What will happen if a star dies?

When the helium fuel runs out, the core will expand and cool. The upper layers will expand and eject material that will collect around the dying star to form a planetary nebula. Finally, the core will cool into a white dwarf and then eventually into a black dwarf. This entire process will take a few billion years.

Is a star dying?

All stars, even our Sun, will someday eventually die. After burning on the main sequence for billions of years, the Sun will expand into a red giant, [+] As the core contracts, it heats up, illuminating the gas in a planetary nebula.

Can you see a star burn out?

Probably not. All of the stars you can see with the unaided eye lie within about 4,000 light-years of Earth. But the most distant ones are intrinsically brighter, have more mass and are therefore likely to die in rare supernova explosions.

Will two stars collide in 2022?

According to study from a team of researchers from Calvin College in Grand Rapids, Michigan, a binary star system that will likely merge and explode in 2022. This is an historic find, since it will allow astronomers to witness a stellar merger and explosion for the first time in history.

How many stars die each day?

We estimate at about 100 billion the number of galaxies in the observable Universe, therefore there are about 100 billion stars being born and dying each year, which corresponds to about 275 million per day, in the whole observable Universe.