All Questions
1,007 questions
20
votes
2
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1k
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Why don't stars in globular clusters all orbit in the same plane?
Globular clusters like Omega Centauri certainly don't seem to be very coplanar at all.
In other words, why doesn't the explanation at Why are our planets in the solar system all on the same disc/...
- 3,662
4
votes
2
answers
481
views
The Opera Neutrino Experiment and the Supernova 1987
So this probably stems from my massive ignorance about post-Newtonian physics but the supernova results of 1987 which measured neutrinos arriving 3 hours before the light from the supernova have been ...
- 174
0
votes
3
answers
323
views
Why is it hard to write a computer program to detect patterns which planethunters is asking us to figure out? [closed]
I recently came across this site http://www.planethunters.org. It shows brightness observed for a star vs time. It asks questions like if star is exhibiting variable or fixed pattern. Later it asks if ...
- 191
4
votes
1
answer
45
views
Contents page of Exoplanets book
I can't find an online contents page for the book Exoplanets, edited by Sara Seager, University of Arizona Press, 2011.
Can you point to such a page, or say what the contents page says?
Qurq
2
votes
2
answers
109
views
What physical interactions actually make single stars leave their binary companions at formation?
From an interesting ScienceDaily article, I read this
Before the groups of stars disperse, binary stars move through their
birth sites and the group studied how they interact with other stars
...
- 3,662
14
votes
2
answers
2k
views
What percent of planets are in the position that they could be viewed edge-on from Earth? (and thus able to undergo transits)
Star number 12644769 from the Kepler Input Catalog was identified as
an eclipsing binary with a 41-day period, from the detection of its
mutual eclipses (9). Eclipses occur because the orbital ...
- 3,662
4
votes
2
answers
52
views
Is it easier to learn more about the seasonal changes in an exoplanet's atmosphere when the exoplanet orbits a binary star system?
From a recent ScienceDaily article, we have this...
Scientists detected the new planet in the Kepler-16 system, a pair of
orbiting stars that eclipse each other from our vantage point on
Earth. When ...
- 3,662
4
votes
2
answers
237
views
Computing period, semi-major axis of binary
I have mass, $g$, and luminosity of each of the stars in a binary system, extracted from a model. I calculated the individual radii from $g$ and the mass. I am trying to compute $a$, but I seem to be ...
McEnroe
4
votes
2
answers
168
views
Balmer lines and their positions
I have two stars, both of which have Balmer lines at the same wavelength positions. The depths of the Balmer lines on each star are different, and the stars are different as well.
Why does this ...
Odinulf
6
votes
4
answers
2k
views
Creating a Star Map
I have a set of data on all the stars (well, to a magnitude of 9 or so) with the values of the following properties:
magnitude,
right ascension and,
declination.
Now I'd like to create a planar (...
Dänu
22
votes
5
answers
117k
views
Can the "Milky Way" galaxy be seen by the naked eye in a clear sky?
Is this photo "real"? Are the stars not super-imposed in the image?
Ian
7
votes
0
answers
113
views
Are there certain alignments in planetary orbits that create interesting effects in the moons or planets? [closed]
We have some interesting examples such as Mercury's perihelion
The planet Mercury is especially susceptible to Jupiter's influence
because of a small celestial coincidence: Mercury's perihelion, ...
- 3,662
7
votes
2
answers
10k
views
How do you measure distance to stars within the galaxy?
I know that for close by stars (<50 LY) we can use the parallax effect. And for distant galaxies we use red-shift (& hubble's constant). So how do we measure how far is a star lets say 50,000 ...
- 39.3k
7
votes
1
answer
434
views
How did enough material from other dying stars accumulate to start our sun and planets?
How far apart do scientists estimate was/were the dying star(s) that supplied the elements that comprise our sun, planet, and us? With stars so far apart and expansion of space (as I understand it) ...
- 921
4
votes
3
answers
106
views
Are our telescopes capable of taking actual images of brown dwarfs?
One nice result from NASA's WISE infrared survey of the sky is the discovery of particularly cool (as in 'not very warm') stars, now called 'Y dwarfs'. This was reported, for example, in
NASA's ...
- 3,662
7
votes
2
answers
411
views
How can Y-dwarf stars have such a low temperature?
A recent article from NASA said they found some stars with temperatures "as cool as the human body." How is this possible? Does fusion still occur in these stars?
yx.
3
votes
2
answers
218
views
Is angular resolution important when we want the spectra of an Earth-like exoplanet?
Right now, our resolution + light gathering power are still far too low to take direct images of exoplanets, so we're limited to subtracting the planet spectra from the parent star spectra when the ...
- 3,662
6
votes
1
answer
5k
views
Most accurate ways to find the average distance between stars in Milky way galaxy
I've already posted here on quora. But, I'm not totally sure if it's the most reasonable method.
Would anyone care to elaborate on how to find the average distance between stars in a given galaxy (...
- 3,662
2
votes
1
answer
241
views
Do red galaxies have red star-lit skies?
I noticed when looking at some deep space pictures, like the Sombrero Galaxy (M104) or the Hubble Deep Field (HDF), I see galaxies of various colors. Does that mean, for instance, than any inhabitant ...
- 199
2
votes
1
answer
38
views
How can we be sure that liquid iron/titanium droplets can form around particulates on hot Jupiters - just as they do on Earth and Venus?
I know that we have some solar system analogs. But is there a limit to it?
- 3,662
3
votes
1
answer
79
views
Is CO2 really a potent greenhouse gas for planets around M dwarfs?
The thing with global warming is that it absorbs infrared (IR) radiation from the planet and reradiates much of it back to the planet (whereas the Sun's peak flux is in the visible region, that is ...
- 3,662
4
votes
4
answers
726
views
What objects/states of objects with absolute magnitude do we know of?
For measuring distances the knowledge of absolute magnitude or luminosity is often crucial, especially for very big distances. Unfortunately we can't measure the diameter of far distant objects and ...
- 721
4
votes
1
answer
94
views
Do stars of higher metallicity have more planets in highly-inclined Pluto-like orbits?
In an answer to a previous question of mine, one that asked about the planar orbits of inner planets, I was told the following (emphasis mine):
On the subject of different solar systems, I would ...
- 3,662
3
votes
1
answer
41
views
Could asteroseismology have a significant potential to unravel the mechanisms of solar cycles that last thousands of years?
Could asteroseismology have a significant potential to unravel the mechanisms of solar cycles that last thousands of years?
And what about solar cycles 1 billion years ago and 2 billion years ago (...
- 3,662
11
votes
2
answers
1k
views
Where does a star's angular momentum go as its spin slows down?
So we know that stars slow down as they age. But total angular momentum must be conserved. Where does that angular momentum go?
The dissipation of Earth's tides somehow transfers Earth's angular ...
- 3,662
3
votes
3
answers
1k
views
Are there formulae for calculating stellar luminosity and effective temperature as a function of age?
Is there a manageable formula or set of formulas or simple algorithms that approximate stellar luminosity and effective temperature (or radius) as a function of stellar age?
I'm aware that accurate ...
- 5,169
9
votes
3
answers
5k
views
Are we capable of discovering planets in the Andromeda galaxy?
I just watched this SpaceRip video on YouTube which shows pictures taken by Hubble while looking into the disk of the Andromeda galaxy to study a certain type of variable star. It occurred to me that ...
- 5,091
7
votes
1
answer
19k
views
What's the difference between a red giant and a red supergiant?
I've seen both theoretical and observational definitions of stars. For example, an AGB star is a star where two sets of nuclear reactions (helium to carbon and hydrogen to helium) are taking place in ...
- 9,785
29
votes
3
answers
24k
views
Is Jupiter a failed star?
In my physics lessons, my teachers have always been keen to tell my class that Jupiter is considered a 'failed star' by scientists. Is this true?
In my own effort I wondered if maybe this could just ...
- 545
9
votes
1
answer
134
views
"Blue Bumper" Stars
I was recently overviewing various massive compact halo object studies (the Anglo-Australian MACHO collaboration and the French I/II EROS collaboration), and they frequently reference "blue bumper ...
- 4,246
5
votes
1
answer
198
views
How are new nebulae being created?
The nebulae we see in the night sky are forming new stars.
The stars are eating up the nebulae and there is no obvious process in which those nebulae are being created to compensate for that.
...
Hermann Ingjaldsson
4
votes
2
answers
156
views
Metal Dilemma: Only very few civilizations per galaxy
This is a question in the area of extraterrestrial life. While life may be possible without it, space travel is probably impossible without metal. Metal is created in stars and heavy metals (above ...
- 625
8
votes
5
answers
221
views
Exoplanet detection via space-based parasol
I remember from watching Cosmos years ago, Carl Sagan suggested an interesting hypothetical method for directly seeing exoplanets. He proposed that in the 'future' we could launch a satellite designed ...
- 727
8
votes
3
answers
11k
views
Solar system, visible stars and deep sky objects
Since I've seen that galaxies are often called "deep sky objects", as opposed to individual stars, does this mean that all visible stars in the night sky actually only belong to The Milky Way Galaxy?
...
dilbert
11
votes
2
answers
4k
views
How can a Population III star be so massive?
How can a Population III star have a mass of several hundred solar masses? Normally the limit is about 100 solar masses.
- 2,350
8
votes
2
answers
3k
views
What elements can be created in the fusion process of different types of stars?
As I understand it fusion inside a sun can produce heavier and heavier elements until some sort of "nucleus size limit" is reached. As far as I understand, the limit is thought to be reached with the ...
- 427
0
votes
2
answers
92
views
Study of exoplanets reaching saturation point [closed]
In recent exoplanet meeting The Next 40 Years of Exoplanets, it was mentioned a few times that the field/topic is becoming saturated.
In what ways is it becoming saturated, and can you see the effect ...
- 235
3
votes
2
answers
333
views
Color Variation in RR Lyrae
I've been doing some research on RR Lyrae stars and haven't been really able to find an answer to this question.
RR Lyrae are well known for their periodic magnitude, and also are usually found in ...
- 4,246
10
votes
2
answers
138
views
Planets capable of life: dead or still alive?
There are some planets that scientists speculate may be capable of supporting life. However, these planets are hundreds of light years away. How can we be sure they are still capable of supporting ...
grassman
104
votes
7
answers
20k
views
Why is there a scarcity of lithium?
One of the major impediments to the widespread adoption of electric cars is a shortage of lithium for the batteries. I read an article a while back that says that there is simply not enough lithium ...
- 2,192
8
votes
3
answers
4k
views
Significance of letters in Hertzsprung-Russell (H-R) diagram
The Hertzsprung-Russell diagram that categorizes star types uses the letter codes O, B, A, F, G, K, and M to indicate a star's temperature/color. Hottest (blue) is O and coolest (red) is M.
What do ...
user921
8
votes
3
answers
359
views
Is a rogue 'exoplanet' classed as a exoplanet?
Given that the term planet strictly (according to the IAU) refers to a body around the sun, rogue planets can't be called that, so I assume they must be called rogue exoplanets?
But do they even ...
- 6,987
9
votes
3
answers
289
views
How would two equally massed stars orbit?
In an empty universe, except for two equally massed stars, how would they orbit? Or, for another example, if the earth suddenly grew to be the mass of the sun, how would they orbit, or interact? Would ...
GunnarJ
11
votes
1
answer
629
views
How many earth-sized planets have been discovered outside the solar system?
How many earth-sized planets have been discovered outside our solar system? Is there a combined registry of them anywhere? Where might I look for more information?
- 779
15
votes
3
answers
468
views
How are newly discovered objects (stars, planets, galaxies...) named?
When a new astronomical object (star, planet, galaxy, comet, etc.) is discovered, what is the official procedure to name it? Who decides about the name of it? Can they be changed in time?
Extra ...
Mehper C. Palavuzlar
14
votes
4
answers
11k
views
Calculations of apparent magnitude
I was attempting to do some calculations of apparent magnitude to help solidify my understanding of the topic, but have been running into some confusion.
According to Wikipedia, the apparent ...
- 3,439
7
votes
3
answers
3k
views
Binary stars' apparent magnitude
If you plot the apparent magnitude of a binary system (so you are unable to see 2 distinct stars) against time, it gives a repeating 'M' effect.
(from http://accessscience.com/)
Assuming one star is ...
- 6,987
16
votes
3
answers
2k
views
What is the probability that a star of a given spectral type will have planets?
There is a lot of new data from the various extrasolar planet projects including NASA's Kepler mission on extra-solar planets. Based on our current data what is the probability that a star of each of ...
- 6,467
21
votes
2
answers
7k
views
How many stars are in the Milky Way galaxy, and how can we determine this?
I have heard multiple estimates on the quantity of stars within our galaxy, anything from 100 to 400 billion of them. The estimates seem to be increasing for the time being. What are the main methods ...
- 3,439
26
votes
4
answers
3k
views
How do the “hot Jupiter” planets get so close to their host star?
Many of the extrasolar planets to date are Jovian sized planets that orbit very very close to their parent star. Traditional planetary formation models say that it is extremely unlikely (if not ...
- 6,467