Questions tagged [star]

Questions regarding large spheres of plasma undergoing fusion.

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1answer
119 views

What types of star do we know are hostile to life (like ours)?

Certainly all stars have enough energy for a planet to host life. But a more magnetically active star is not preferred because solar ejection could strip planets of their atmosphere. What's the right ...
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2answers
110 views

What sun-like star is closest to earth/sun? [closed]

This list says that Tau Ceti is very like the Sun (spectrally). Others are predominantly red dwarfs. Is Tau Ceti closest star which is quite like the sun according to some criteria?
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231 views

Can life on earth be supported by only a Red Dwarf star or a White Dwarf(state still hot not cooled enough yet)?(Provided it is near to the star)

Can a red dwarf star or a white dwarf have enough energy to support life on earth? How it will change the climate and the seasons of earth if it is our only star? (energy source)(Expecting it to ...
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1answer
138 views

Do narrow lines in the spectra of O- and B- type stars always indicate magnetic fields?

I was reading a paper on the differential emission measures of a set of hot O- and B- type stars. As the authors discuss in Section 3 (page 959), two stars, $\tau$ Sco and $\theta^1$ Ori C, have ...
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1answer
34 views

Relationship between galactic rotation and stellar lifetime

I have read that the lifetime of stars is much less than the period of rotation for a spiral galaxy. For example https://www.coursera.org/learn/evolvinguniverse/lecture/wlYhz/the-origin-of-spiral-arms ...
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3answers
148 views

Position of specific stars in the sky as a function of time

I'm a beginner in astronomy and I'm trying to figure out how to model the positions of stars in the night sky mathematically (ie a function which spits out azimuth and altitude as a function of time). ...
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1answer
152 views

How can the temperature of stars can be determined by their color?

How do you determine the temperature of a star by color?
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1answer
119 views

Why planets and stars are always round/oval in size? [duplicate]

What kind of stability it provides to each and every celestial body that each one them are round in shape?
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1answer
68 views

Is there any difference among exoplanets in composition due to host star?

Simply put, would, say, rocky planets orbiting red dwarfs have a noticably different chemical makeup than rocky planets orbiting B-type main sequence stars? Mutatis mutandis gas giants and the other ...
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1answer
303 views

Black Dwarf Capabilities

Can a black dwarf be suitable for manned exploration, once it cools down? And potentially used for space mining?
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1answer
139 views

What makes an exoplanet to orbit around its star backwards?And why did we consider our orbital movement to be forward?

I read somewhere that an exoplanet in the name of HAT-P-7B orbits its star backwards.Why? And why did we consider our orbital movement to be forward?Is there some scientific reason to consider the ...
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1answer
96 views

Is the age of the solar system equal to the age of meteorites?

I've read articles that state the age of the solar system has been determined by measuring the amount of decay of isotopes in some meteorite, which has demonstrated that the lead isotopes in the ...
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3answers
402 views

Our Sun already a White dwarf?

I watch the discovery science channel a lot & enjoy the material about space, stars, planets, etc. In one episode the narrator states our Sun will one day become a white dwarf star. The size of ...
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1answer
3k views

How to calculate observer's latitude from declination and culmination of a star?

From gcseastronomy.co.uk: A star culminates at 50°. It has a declination of +20°. What is the latitude from where it is observed? What is the relationship between a culmination, declination, and ...
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0answers
37 views

How to fit lorentzian to lyman alpha cross section?

This is my data and purpose of this assignment is to fit a lorentzian to this data. And.. i dont know how to do that....:( First, there is sharply lowered region. Couple of hours of googling isn't ...
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3answers
162 views

Is star a necessary phase in black hole lifecycle?

It now seems general fact that when a massive star core collapses at the end of its lifecycle it forms a black hole, can a black hole be formed skipping the star phase altogether?
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2answers
4k views

Fate of Jupiter when our sun dies

Five billion years from now, the sun will have grown into a red giant star, more than a hundred times larger than its current size. While this metamorphosis into the giant star will change the solar ...
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1answer
59 views

Is it possible for a solar flare in one star to influence the chances of a solar flare in another star?

Can a solar flare reach far enough to travel from one ordinary star to another? If so, how can that solar flare affect the following star?
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2answers
208 views

Can Two Stars of One Same Type Orbit Each Other?

This is a simple, textbook definition of a binary star orbit. One low-mass star orbits a higher-mass star in a narrow but definitive center. For example, the high-mass star would be our own sun--a G-...
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2answers
424 views

Detecting habitable planets

From my understanding we detect planets by measuring dips in light intensity from the star the habitable planet is orbiting when it passes by it. There are 2 things I don’t understand about this ...
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2answers
74 views

Observing eclipsing binaries

In a matter of weeks, I will be performing my first observation using a 25-cm Newton telescope (+CCD camera) and would be grateful for advice regarding an otherwise basic research that I have decided ...
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3answers
81 views

How do I obtain the brightness of a star in the night sky?

I am planning to conduct a research which involves observing the brightness of a star. So far, I haven't been able to obtain much information as to how I may go forward with the observation process. I'...
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110 views

What would happen if a star passed through the barycenter of two binary stars?

I was doing some research on Alpha Centauri A and B, and thought to myself: 'What would happen if something passed directly through the barycenter of these two stars?' I may theorise that a passing ...
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2answers
244 views

What does this figure imply about the luminosity of pre-main-sequence stars?

Check out Figure 1 in http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1955PASP...67..154H&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf . It seems to ...
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2answers
445 views

Why is the track of the subgiant stage almost horizontal on the HR diagram?

It is stated that: After the main sequence, as fusion weakens or stops in the core, outward radiation weakens. The helium core contracts and heats up. Gravitational energy is converted to thermal ...
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1answer
170 views

What is equation of straight line for a ideal blackbody on the color color diagram?

The color-color diagram is a plot between $U-B$ vs $B-V$ values. For a ideal blackbody, what is the equation of this line? In other words, what does the linear relation between $U-B$ and $B-V$ look ...
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3answers
141 views

What can a regular person use to view the stars?

My favorite thing in this world is looking up at stars but I live in NYC so I can't ever see stars. I was wondering if anyone knew of a device I can attach to a smartphone that would let me look up at ...
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1answer
478 views

Brightest star visible from Italy and Argentina

A friend of mine tends to ask crazy question about everything. Today he ask me what is the brightest star that is visible on both the hemisphere and in particular from Italy and Argentina. I tried to ...
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1answer
117 views

What are six different methods to measure distances in Astronomy?

What are six different methods to measure distances in Astronomy in regards of their respective range in terms of astronomical objects? So far I can name 4: Parallax method, radar ranging, main-...
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2answers
115 views

What is the spectral reflectance of starlight in a close binary?

In a close-orbiting binary pair, a small but significant fraction of the light from each star falls upon the other, and the result has to be carefully modeled to simulate the observed spectrum of the ...
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1answer
69 views

Bright pulsating light [duplicate]

Was looking at the sky and I see a satellite , turned around and saw another light , but this light was pulsating like a strobe light , definitely not a plane , next thing I know the light goes out ...
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1answer
68 views

What am I looking at?

I am in Northampton England and every night in the SW sky is a very bright, white light that twinkles. It visibly appears to be moving towards the west but appears pretty much the same start place ...
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1answer
370 views

Why Helium-burning Stars are found in a Horizontal Branch?

Why Helium-burning stars are found in a horizontal branch on the H-R diagram? Why do they have roughly the same luminosity?
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94 views

Do hypervelocity stars have Oort clouds?

If you had a hypervelocity star travelling through space incredibly quickly, would the hypervelocity star's Oort cloud remain intact? Would the high speed of a hypervelocity star shed the comets and ...
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2answers
209 views

When does a star rise with the sun?

Problem: Suppose an observer's latitude is 45 S and a star's RA/DEC is 3h15min/41S. On what date will the sun set with the star. I have been stuck on this problem for a while. I found out that the ...
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4answers
826 views

How can a red giant grow so big?

Supposedly when the sun becomes a red giant, it will grow big enough to swallow Earth. However, this requires the radius of the sun to expand by a factor of approximately 215×, meaning its volume ...
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1answer
572 views

Can a star eat a black hole?

I know there are stars much larger than the sun and that we've discovered "small" black holes, so, let's say that the Pistol Star, which is at least 80x the mass of the sun, and the smallest known ...
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1answer
417 views

Given a star's ra, dec how can I compute one pair of lat, long and time where the star would be at zenith?

As the questions says, I have the celestial coordinates of a star(ra, dec). My trigonometry is not so great so I haven't managed to figure out a solution to this. I want to find a place (lat, long) ...
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110 views

Is there a term to describe all stars that are not neutron stars or white dwarfs?

I am looking for a official term that describes all stars that are not neutron stars or white dwarfs. "Still burning stuff stars" or "ordinary stars" are all I have been able to come up with. Is ...
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1answer
321 views

Is it likely that intergalactic stars would still retain their planets?

Given that we've discovered hundreds of intergalactic stars (IGs), and that most stars have planets, what do we know about the likelihood of IGs retaining their planets after being ejected from their ...
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2answers
326 views

Finding the radius of a star in arcsec

If i know the radius r of a star in cm, how can I convert it to arcseconds? For example, if I have a star with r = 3.18e13 cm, and distance to the star d = 220 parsecs, what is the relation to ...
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0answers
197 views

How is Phosphorus made in in stars? [duplicate]

What elements are required to fuse into phosphorus in a star. Can someone give me a step by step process please e.g 4 hydrogen nuclei fuse into one helium nuclei and then 3 helium nuclei fuse ...
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1answer
77 views

Color changing celestial body near the moon [closed]

While I was star gazing yesterday in the night time I observed a celestial body( probably a star ) flaunting various colors and was residing near the moon from the angle I saw it. It appeared to be ...
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2answers
154 views

Can hot Jupiters cause solar flares?

I'm very new at Astronomy, and my knowledge is sparse. I've tried to be conscientious about my Wikipedia research but there's going to be a lot of things I don't know. Thanks for your patience. ...
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5answers
549 views

Why is sun's photosphere a million times less dense than air at the surface of the Earth?

Sun's photosphere is about 19 times as hot as Earth's surface. (Source: http://solar-center.stanford.edu/vitalstats.html) But Solar surface gravity is about 28 times terrestrial surface gravity. So,...
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1answer
177 views

Creating an HR diagram from tabulated stellar data

I teach statistics and study Astronomy. I'd like to create an activity for my statistics students using star data. They could enter the data into Excel and create an HR diagram. We are currently ...
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1answer
292 views

Core collapse supernova vs Neutron Star

I am reading about massive stars and their final consequences. what I understood is massive stars after throwing out their outer envelop with masses > 1.4 solar Mass turn into neutron stars. But I ...
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1answer
294 views

Central temperature and pressure for constant density vs linear density model of stars

I just derived the pressure and temperature profile for a linear density model of a star. If I compare the profiles of pressure and temperature for a constant density model of stars, I see that the ...
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1answer
218 views

How do sunspots move seen from the side?

Sunspots rise vertically? Do they float on the surface like oil? Do they flow up or down vertically from the Sun's core like a lava lamp?
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1answer
4k views

Why do stars twinkle but the Sun doesn't (I'm asking this because the Sun is also a star) [duplicate]

My friend asked me "Sun is also a star then why doesn't it twinkle like other stars" I brought this question here so that I have (and have more) infomation on this topic.

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