# star's questions - English 1answer

580 star questions.

### 5 The formation of new stars as depicted in Feynman's lectures

2 answers, 121 views star star-formation
I've stumbled upon this curious passage addressing the formation of stars in Feynman's lectures on physics: Whether we have ever seen a star form or not is still debatable. Figure 7–12 shows the ...

### 1 B-V to U-B colour index

3 answers, 155 views star spectral-type
Is there a formula to convert the B-V index to U-B index or are they totally different and separate observations and can't be convert like you can with Fahrenheit->Celsius? (Updated) I know F->C ...

### 1 Ratios of magnitudes instead of differences

3 answers, 38 views star observational-astronomy magnitude
The color index in the photometric system is defined by the differences in magnitudes between two wavelength filters, which gives the ratio of intensities. For example, to determine the B-V index, you'...

### 3 Orange light that rises quickly and moves of to the righ

I have recently noticed an orange "star" (or what I presume to be a star), rise above the hill line behind my home. It rises later than every other star and rises within a few hours while the other ...

### 3 Dataset containing list of known globular clusters

Does anybody know if there is an existing dataset that consists of all known star clusters, their name, and their apparent dimensions or similar? Is it possible to make a query to, or download all ...

### 4 We are in Green Lake, WI, 8/12/18, seeing bright orange “planet”/“star” almost due South, perhaps 20 degrees above horizon, what is it?

1 answers, 84 views star planet
I have a “sky” app on my ipad and expected it to be Mars, but my app shows Mars just below horizon and closer to East. Oh, I should add that we saw this about 10:15 tonight. Hanging out watching ...

### 1 Are there simplified M-L, M-R, and lifetime equations for non main sequence stars?

0 answers, 23 views star stellar-evolution main-sequence
To give some context - I am trying to create a simple program that outputs the stellar properties of a star when given its initial mass and current age. e.g. Input Initial Mass = 2e30kg Age = 4.6 ...

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

2 answers, 160 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 ...

### 7 Why is H_delta prominent in type A stars?

I understand factually that H$\delta$ lines are most prominent in type A stars and less so in more extreme types of stars on the H-R diagram. However I was wondering the reason for why they are not ...

### 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 ...

### 6 Currently proposed ways to distinguish between a really big planet and a really small star

2 answers, 290 views star planet exoplanet classification
The Next Big Future article Rogue Exoplanet 12.7 times bigger than Jupiter is 20 light years away Astronomers using the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) have made ...

### 42 How can 'HD 140283' be older than the universe?

2 answers, 7.815 views star universe
Scientists have known about the star HD 140283, informally nicknamed the Methuselah star, for more than 100 years, since it cruises across the sky at a relatively rapid clip. The star moves at about ...

### 2 What are the so called clouds of dust and gas made of?

1 answers, 97 views star dust gas
We constantly read about "clouds of dust and gas" surrounding a (or being the initial state of a) star, but what elements constitute such dust and gas?

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

2 answers, 95 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). ...

### Stellar Classification and Star RNG

1 answers, 40 views star mathematics resource
I found a table that was based on data from 2003 for Stellar Classification, and I can't get to the given data source. I plan on using the table as a basis for a program that spits out random star ...

### 2 If any object could become a black hole, could any object become a neutron star?

2 answers, 211 views star black-hole gravity neutron-star
A black hole doesn't necessarily need to form from a star; theoretically, it could form from any extremely dense object. In fact, many astronomers differentiate certain black holes, like supermassive ...

### Almost unseeable light moving over nightsky. What is it?

0 answers, 47 views star light movement
Sometimes when I look up at the sky at night, I can see something moving. It’s so small that I barely can see it, but I can’t see it when I look directly at it. I need to look beside it to see it. It ...

### 2 Electron Degeneracy Pressure and the Pauli Exclusion Principle

2 answers, 525 views star gravity degenerate-matter
I have read that what keeps white dwarfs from gravitational collapse is electron degeneracy pressure. How does this pressure prevent further collapse, and how is it related to the Pauli Exclusion ...

### 1 At what speed does something have to travel away from us for it to red shift enough that it becomes invisible to the human eye?

1 answers, 111 views star redshift spectroscopy
Are there stars, galaxies etc that we cannot see because they are traveling too fast and their spectrum is shifted below our visible range? From what I understand, red shift is caused by stars and ...

### What could this have been? [duplicate]

A few weeks ago me and a friend were at my pool. It was night time, and I looked up at the moon. Right beside the moon was this bright orange looking star. It looked really creepy, but I wasn’t sure ...

### 1 What are these objects on the night sky generally between 8:00 and 11:00 PM? [duplicate]

Many time I saw a moving star in the night generally been 08:00 to 11:00 PM. It is not any satellite, because it move in all directions, although it moves in a straight line. Sometimes from north to ...

### 1 Has the sun become way brighter the last years?

3 answers, 779 views star the-sun earth
Up to last year, I never got blinded by the sun in everyday situations (e.g. running towards it), at no time of the year I was. But since last christmas, it occured to me more often that I cannot ...

### 1 Struggling to use my new telescope

1 answers, 61 views star planet telescope amateur-observing
I recently got my first telescope, a Bushnell reflector telescope. I spent a good while setting up my alignment. And I can see the moon perfectly! I went to look at another, Mars. I got it aligned in ...

### -6 Black-hole becoming a star again - follow-up question [closed]

Some questions have been posed about black holes becoming stars again once they attract enough hydrogen/atomic matter from another star. Some answers were a forceful NO. Never. However - let's ponder ...

### 2 Does the mass of a collapsing star change?

Does a star, when collapsing into a neutron star, or even a black hole, pick up any significant relativistic mass due to its rapid collapse rate?

### 4 How is the Lithium Depletion Boundary used to determine the age of a stellar cluster?

1 answers, 297 views star star-formation luminosity age
According to my understanding of Soderblom et al. (2014), lithium ages of stars are determined as follows: Determine lithium abundance from equivalent width measurement of Li$_{\mathrm{I}}$ ...

### 1 Concerning the “Lithium test” for Brown Dwarfs

Both low-mass PMS (pre-main-sequence) stars and young brown dwarfs can fuse lithium in their cores and the lithium can be depleted throughout the star/brown dwarf very quickly. Wiki. Then the Li I ...

### 1 a star in the sky thay moves back and forth way up in the sky [duplicate]

did anyone watch the sky in the west at 1:15 am.On 7-13-18. a star moving around in the greenup ky UT WOULD go back and forth

### 2 How to construct a sky map

First of all, I have very basic knowledge of astronomy so sorry if I make some mistakes in my terminology. I'd like to plot the Southern Cross. I can find the name of its 5 stars. Also, I have some ...

### 1 What are the possible star fuels?

3 answers, 139 views star core
I always thought the only fuel for a star was hydrogen, which is fused into helium. But while reading some questions and answers here in ASO, I saw phrases like "This balance stays relatively stable ...

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

1 answers, 68 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 ...

### 2 How space scientist keeps the track of the stars?

In billions of stars, how space scientist keeps the track of the stars ? There is a star called KIC 8462852, I saw that picture, star is so small from the earth. It has higher chance to miss that ...

### Bright light moving across sky heading north [duplicate]

This morning I saw a very bright light move towards the north. It looked as if a piece broke off. I was wondering if this may be a comet, or a rocket? This light was much brighter than surrounding ...

### 2 Stars in constellation patterns by catalogue number?

5 answers, 485 views star constellations
I need a resource that can tell me the stars that make up a constellation (pattern), preferably by Henry Draper or some catalogue number? All i can find is lists of every star in a constellation (area)...

### 4 Why do photos of Earth always have a black background?

if we are in the milky way, and people are able to take photographs from Earth that look like this: Then how come almost all of Earth's photos look like this? In the first photo, we are seeing what ...

### 4 How Can I View KIC 9832227?

1 answers, 394 views star binary-star
I've heard that KIC 9832227 is a contact binary star system that is expected to merge and explode as a "red nova" sometime in the next ~5 years or so. http://www.sciencemag.org/news/2017/01/colliding-...

### 21 Is our sun in a star cluster?

2 answers, 5.388 views star the-sun globular-clusters
Sorry for the absolute begginer question here, but is our sun a part of some globular cluster? It is something related to Virgo supercluster?

### -2 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?

### 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, 1.429 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, 661 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, 46 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 ...

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

1 answers, 126 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 ...

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

4 answers, 3.619 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 ...

### 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, 102 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?