All Questions
12 questions
42
votes
3
answers
7k
views
How did Hubble know the red shift difference between "moving away" and "old"?
My 9yo daughter is very into space at the moment and asked a question that my physics knowledge (6th form college, 20 years ago) is way too poor to answer.
Her space book tells us that as stars age, ...
- 521
4
votes
1
answer
71
views
Long-lived supernova remnants?
We cannot see the supernova remnant of the star that triggered the formation of the Sun and the Solar System, as the remnant dispersed and became mixed into the interstellar medium. So I am wondering, ...
- 6,733
6
votes
2
answers
624
views
How to determine the age of a star using asteroseismology?
I keep reading that a standard way to determine the age of a star is asteroseismology, and I tried to learn more about it. I am wondering if somebody could help me to describe the method in simple ...
- 5,657
2
votes
1
answer
209
views
How can a very old star be formed among Population III stars?
After looking at some articles about old stars, (this, that, and this Wikipedia article), I thought about how such an old and small star could have formed. As the early universe had very massive, ...
- 6,733
1
vote
0
answers
53
views
Is a star with 2/3 solar masses and 9/10 solar radii still in the main sequence?
As far as I know, K-type and G-type stars (among others) grow in radius as they age, eventually leading to red giant phases.
My question is, would a star that is about 0.66 solar masses and 0.94 solar ...
- 403
2
votes
0
answers
121
views
Stellar age determination - code
I'm trying to determine the age of some stars. I have many parameters that characterize these stars: $T_{eff}$ ,log ${g}$ ,$[Fe/H]$, $V$... I've tried to use the isochrones package but so far no ...
- 391
6
votes
3
answers
376
views
Is there a stellar database that indicates how long ago stars in our Galaxy formed?
There are several ways of determining the age of a star: its position in the HR diagram, the presence of a protoplanetary disk, it belonging to a cluster...
When did the stars in our Galaxy form? Do ...
- 17.7k
11
votes
2
answers
539
views
Could a star closely orbit a black hole long enough for the star to have lost 0.5B+ years to time dilation?
I was wondering how stable a close star-black hole system could plausibly be, and thus how much time a star could plausibly miss out on (from an outside observer's perspective) due to being in an ...
- 387
6
votes
1
answer
510
views
Can someone calculate the age of the KOI-4878 star?
The star’s low metallicity and fairly high space velocity suggest that KOI-4878 is older than the Sun.
But I don't know how to calculate an estimation for the age.
KOI-4878 data on Simbad
user30548
4
votes
4
answers
4k
views
Why is the main sequence often called 'zero age' main sequence?
The main sequence stage for a star begins after it stars burning hydrogen into helium. This is often referred to as the zero age main sequence.
This is confusing since stars have already lived ...
- 822
4
votes
1
answer
293
views
Where are we in an approximate timeline of the possibly habitable universe?
Our universe is supposedly 13+ billion years old and our Sun is a third generation star. It seems to me that we are now in a relatively young stage of the universe. How many generations of stars will ...
- 141
4
votes
1
answer
677
views
How is the Lithium Depletion Boundary used to determine the age of a stellar cluster?
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$_{\mathrm{I}}$ ...
user5341