# star's questions - English 1answer

557 star questions.

### -2 What sun-like star is closest to earth/sun?

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?

### 4 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 ...

### 14 When a star reaches the red giant phase, why does it become more opaque?

2 answers, 1.394 views star red-giant
Please refer to this answer from Quora: ... a star will become a red giant before it begins burning helium. In fact, it will bloat into a red giant while still burning hydrogen in a shell on the ...

### 16 What is the upper and lower limit of temperatures found on stars?

3 answers, 641 views star temperature
What are the most extreme temperatures (both hot and cold) stars have been detected at? Is there an upper and lower limit for the detected temperature of stars?

### 1 What factors makes a star big in size(Physically)?Is the size of the nebula a relevant factor?

1 answers, 42 views star stellar-evolution nebula
(Our sun compared to some of the known stars) I know that the star is born in a nebula.Do only a extremely gigantic nebula give rise to large-radius star or is there any other factors related?

### 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 ...

### 2 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 ...

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

2 answers, 114 views star red-giant
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 ...

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

1 answers, 122 views star the-sun orbit exoplanet
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 ...

### 1 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 ...

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

1 answers, 63 views star binary-star albedo
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 ...

### 13 How Would a Neutron Star Actually Appear?

4 answers, 3.241 views star observation pulsar
Having seen many pictures produced by artists of neutron stars and planets that orbit some of them, I was wondering how a pulsar would appear to a human being, in visible light (assuming the intense ...

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

2 answers, 77 views star coordinate
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). ...

### 2 Relationship between galactic rotation and stellar lifetime

1 answers, 29 views star galaxy rotation spiral-arms
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 ...

### 5 Less stars in the night, compared to 15-20 years back

I am not sure if my question is true or not. But this is what I observe regularly. When I was young and when I look at the sky, there were too many many stars were there. But now, from few months I'm ...

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

1 answers, 100 views star planet celestial-mechanics
What kind of stability it provides to each and every celestial body that each one them are round in shape?

### 4 Can the explanation of Tabby's star KIC 8462852 be an intervening planet in orbit around another star?

Can an intervening planet in orbit around a nearby star cause periodic occultation? Please excuse the crude text graphics: ...

### 5 Black Dwarf Capabilities

1 answers, 263 views star star-formation dwarf-star
Can a black dwarf be suitable for manned exploration, once it cools down? And potentially used for space mining?

### 4 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 ...

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

1 answers, 77 views star planet solar-system
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 ...

### 2 Our Sun already a White dwarf?

3 answers, 128 views star dwarf-star
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 ...

### 3 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 ...

### 6 What's in the center of a Galaxy?

4 answers, 7.339 views star galaxy light
Ok, so it's supposed that there is a black hole in the center of any galaxy, that makes my head explode because: There is light in the center of the galaxy, but it is supposed that black holes, also ...

### 3 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 ...

### 4 Is star a necessary phase in black hole lifecycle?

3 answers, 128 views star black-hole
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?

### 9 How much mass will the Sun have when it becomes a white dwarf?

2 answers, 1.368 views star the-sun white-dwarf
In 4 billion years, when our Sun sheds all of its outer gas layers and turns into a white dwarf, how much mass will the white dwarf have compared to what the sun has today? Will the planets still ...

### 2 Fate of Jupiter when our sun dies

2 answers, 883 views star the-sun jupiter gas-giants
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 ...

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

1 answers, 48 views star the-sun solar-flare interstellar
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?

### 4 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 ...

### 1 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-...

### 4 Detecting habitable planets

2 answers, 363 views star planet exoplanet habitable-zone
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 ...

### 3 Observing eclipsing binaries

2 answers, 54 views star binary-star photometry
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 ...

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

3 answers, 64 views star telescope photometry
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'...

### 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 ...

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

2 answers, 56 views star luminosity
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 ...

### 1 If there are neutron stars, would most stars be considered “proton stars”?

For example, the Sun is a giant sphere of positively charged plasma. About 72% of the elements in it are protium. This means that these protium atoms would have had to lose their electrons, right? If ...

### 1 What are six different methods to measure distances in Astronomy?

1 answers, 68 views star galaxy
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-...

### 3 Brightest star visible from Italy and Argentina

1 answers, 265 views star night-sky
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 ...

### 1 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 ...

### 1 What am I looking at?

1 answers, 61 views star planet satellite
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 ...

### 6 What does designation VY, NML, UU in star names stand for?

1 answers, 1.284 views star naming
I've read the a IAU page on the subject but i am no closer to understanding how this works. Also did search the already asked question, but didn't see anything on the subject. What does bolded item ...

### 19 Is there a theoretical maximum size limit for a star?

3 answers, 4.873 views star size
Some stars are simply huge. Eventually, though, wouldn't there be simply too much pressure or mass for the star to sustain itself? Wouldn't it eventually collapse into a black hole? Is there a ...

### 4 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?

### 4 What is this rapidly twinkling red, blue, and white star I saw?

5 answers, 4.876 views star night-sky
Last night, I was on my balcony at 1AM (PST) and I looked up and saw two stars near the horizon (I'd guess ~30 degrees above the horizon), and they were "twinkling" about twice as fast as other stars ...

### Do hypervelocity stars have Oort clouds?

2 answers, 46 views star oort-cloud
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 ...

### When does a star rise with the sun?

1 answers, 107 views star the-sun declination right-ascension
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 ...

### 7 How can a red giant grow so big?

4 answers, 219 views star red-giant
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 ...

### 2 Can a star eat a black hole?

1 answers, 163 views star black-hole gravity astrophysics
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 ...

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

1 answers, 58 views star coordinate
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) ...