A star is found with a luminosity 2*104 greater than the sun and a photosphere (`surface’) temperature of 3,000 K. Is the star fusing hydrogen in its core?

Q: Star A and Star B are both on the main sequence. Star A is 74 times more luminous than Star B. What…

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Q: Two stars of the same diameter or observed to have surface temperatures of 4000 Kelvin and 16,000…

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Q: What is the ratio of the percent of metals in extreme Population I stars (3%) to that in extreme…

A: Given data: The percent of metals in extreme Population I stars is Npop I=3%  The percent of metals…

Q: What would be the approximately luminosity of a main sequence star with a temperature of 9,000°C ?…

A: Temperature = 9000° C=9273.15 K Luminosity will be given by following formula:L=σT4 L is the…

Q: Which stars are associated with a planetary nebula? black holes, neutron star's, white dwarf or main…

A: Required : What are planetary nebula associated with.

Q: require(s) that a young hot star (T ≥ 25,000 K) be relatively nearby.

A: Correct answer is Emission nebula

Q: A star is observed with a surface temperature of 3,000 K and a luminosity of 100,000 solar…

A: Given , Temperature = 3000 K Solar Luminosity = 100,000  Now , mass and luminosity are related by…

Q: A star with a radius twice that of the Sun and a surface temperature twice that of the Sun, will…

A: Luminosity of a star of radius R and surface temperature T is given by L=4πσR2T4 where is the…

Q: A group of graduate students, bored during a cloudy night at a the observatory, begin to make bets…

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Q: A newly discovered bright star has a luminosity of 78.4×1026 W. What is its temperature if it has a…

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Q: A star with a radius three times that of the Sun and a surface temperature twice that of the Sun,…

A: 144

Q: Each choice below lists a spectral type and luminosity class for a star. Which one is a hot main…

A: Luminosity of main sequence star is class V and spectral type of hot main sequence star is O.

Q: If a neutron star has a radius of 9.12 km and a temperature of 3.63 x 106 K, how luminous is it in…

A: 1)Using stefan's lawP = σ A T4Where P is the power σ is the stefan's constant A is the area of…

Q: A star with spectral type A0 has a surface temperature of 9600 K and a radius of 2.2 RSun. How many…

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Q: The luminosity of Spica is about 5x1030 Joules/second. A mass MH of Hydrogen that undergoes…

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Q: At rest, hydrogen has a spectral line at 144 nm. If this line is observed at 168 nm for the star…

A: Given that Hydrogen has a spectral line at λ= 144 nm =10-9m This line is observed at λ'= 168 nm=10-9…

Q: The percentage of helium used immediately during a star’s helium flash phase is

A: It is a very brief phase

Q: You are observing a different star which has a normal measured flux of 29.7 photons per second. The…

A: Normal measured flux = 29.7 photons per second Decrement in the brightness of star =…

Q: Which main-sequence star would be the least luminous?   a. A   b. B   c. F   d. G   e. K

A: Answer:) option(a) A alpha century A is least luminous because its absolute magnitude (+4.4) which…

Q: A star has a parallax angle of 0.0270 arcseconds and an apparent magnitude of 4.641. What is the…

A: Since we only answer up to 3 sub-parts, we’ll answer the first 3. Please resubmit the question and…

Q: If the Sun is well approximated by a black body with a temperature of 6,000◦ K, then how does its…

A: By using Stefan Boltzmann's Law

Q: On a H-R diagram for main sequence stars, as temperature increases, brightness usually increases…

A: Required: Variation of brighness with  temperature in HR diagram.

Q: In the laboratory, the Balmer alpha line has a wavelength of 656.3 nm. If the line in a star’s…

A: Rest wavelength of the first balmer line of hydrogen is 656.3 nm. Star spectrum appears the…

Q: You are observing a different star which has a normal measured flux of 29.7 photons per second. The…

A: Ans)Given dataRadius=4.1-108mmass-1.6×1030 kglumminosity=1.3×1026wNormal measured flux=29.7…

Q: supernova remnant is now 4.75 pc in radius and is expanding at 1,600 km/s. Approximately how many…

A: Given 1 pc = 3.1 × 1013 km 1 year = 3.2 × 107 s Radius of supernova remnant = 4.75 × 3.1 × 10 13 km…

Q: Why is it, that a star which uses up the hydrogen in its core, swells to enormous size and changes…

A: Required : Why does a star which uses up the hydrogen swells to enormous size and changes color.

Q: For each statement concerning main sequence stars, select T True, F False, G Greater than, L Less…

A: Required :  True or False, greater, lesser, equal.

Q: What is the size of a star with a temperature three times as hot as the sun and the luminosity of…

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Q: In a laboratory, the Balmer-beta spectral line of hydrogen has a wavelength of 486.1 nm. If the line…

A: Given data:  Rest Wavelength (λ0) = 486.1 nm In star's spectrum wavelength λ = 486.7 nm Required:…

Q: An astronomer is observing a binary star that is 15 pc away. The two stars have an orbital…

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Q: Assume that when a certain main sequence star becomes a giant gas, its luminosity increases from L…

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Q: A solar type star evolves into a red giant with a luminosity 1000 L⊙ and radius of 1 AU. Determine…

A: Given: Luminosity of red giant is L=1000Lsun=103×3.846×1026 W Radius of red giant is r=1…

Q: Vega Star of radius (1.6832) million km emit a) thermal radiation as a black body radiation at…

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Q: A star with spectral type A0 has a surface temperature of 9600 K and a radius of 2.2 RSun. How many…

A: Given: Tstar = 9600 KRstar =2.2 RsunTsun=5778 KMstar = 3.3 Msun

Q: 50,000 20,000 Surface Temperature (C) Would the surface temperature of the stars classified as white…

A: Surface temperature of white dwarfs is around 20000K And for giant it is 2500 to 4000K

Q: A supernova remnant is now 3.85 pc in radius and is expanding at 3,350 km/s. Approximately how many…

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Q: Topic: Life cycle of stars Q. If a giant star is cooler than a main sequence star, why does it have…

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Q: The lowest mass for a true star is 1/12 the mass of the sun. What is the luminosity of this star (in…

A: Mass of the star, M star=1/12 times the mass of sun We are restricted to take the exponent of 4 for…

Q: What is the life expectancy (in years) of a 10 M⊙ main-sequence star? What is the life expectancy…

A: Required : The life expectancy of stars.

Q: Which of the following stars has the highest surface temperature? Treat the star as a blackbody.…

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Q: What is the mass of a star with a main-sequence lifetime of 6 billion years

A: Given: The main-sequence lifetime of a star is 6 billion years.

Q: What is the lifetime of a 10-solar-mass star on the main sequence?   a. 3.2 × 107 years   b. 320…

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Q: A star with spectral type A0 has a surface temperature of 9600 K and a radius of 2.2 RSun. How many…

A: Disclaimer: Since you have asked multiple question, we will solve the first question for you. If you…

Stellar evolution

We may see thousands of stars in the dark sky. Our universe consists of billions of stars. Stars may appear tiny to us but they are huge balls of gasses. Sun is a star of average size. Some stars are even a thousand times larger than the sun. The stars do not exist forever they have a certain lifetime. The life span of the sun is about 10 billion years. The star undergoes various changes during its lifetime, this process is called stellar evolution. The structure of the sun-like star is shown below.

Red Shift

It is an astronomical phenomenon. In this phenomenon, increase in wavelength with corresponding decrease in photon energy and frequency of radiation of light. It is the displacement of spectrum of any kind of astronomical object to the longer wavelengths (red) side.