Questions tagged [modeling]

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2
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2answers
108 views

Estimate prevalence of ʻOumuamua-style interstellar obects inside Jupiter orbit now that C/2019 Q4 (Borisov) is found?

Now we know two of them, so maybe it's not an outlier. We have two points so we can draw a line. How many similar macroscopic objects should be zipping through space at ~30 km/sec so that we would ...
4
votes
1answer
34 views

How to model and subtract nebular emission lines from stellar spectrum

I have optical stellar spectra from a star forming region with spatially varying nebular background. I want to subtract the nebular lines from the stellar spectra (which are varying in intensity from ...
3
votes
1answer
64 views

Brown Dwarf Cloud Models

There has been research that suggests that the changing brightness of Brown Dwarves are due to bands of Iron/Silicate clouds. Several models have been made that supports that hypothesis. My question ...
1
vote
0answers
16 views

Brown dwarf cloud models [duplicate]

There has been research that suggests that the changing brightness of Brown Dwarves are due to bands of Iron/Silicate clouds. Several models have been made that supports that hypothesis. My question ...
1
vote
1answer
75 views

Dynamical modelling of galaxies with counter-rotating components using the Schwarzschild method

I am currently trying to understand dynamical modelling using Schwarzschild's method. I have been doing some reading the past days, but I suspect that I am getting something really wrong. According to ...
22
votes
1answer
2k views

When will the number of stars be a maximum?

There are very roughly a "mole" of stars in the universe. Wikipedia quotes an estimate of $3 \times 10^{23}$ though the number is associated with some debate and uncertainly. I'd like to know if ...
1
vote
0answers
15 views

Clarity on dust extinction terms and implementation: R_V, A_V, and E(B-V)

I have created a model galaxy spectrum using STARBURST99 and want to compare it to an observed spectrum of a particular galaxy. I understand that I need to redden ...
3
votes
0answers
74 views

What is the actual visual characteristics of a black hole?

Is there a safe distance in which a black hole can be observed with the human eye? What is a safe distance? I have seen many computer simulated and artist renditions, and I am not sure if they ...
1
vote
0answers
33 views

How do you fit a model SED to an observed galaxy spectrum with photometric data?

I have a spectrum of a galaxy from HST data and SDSS data (resulting in a nearly continuous SED from the FUV~1000 Angstroms through infrared). I have created a model SED with the galaxy simulation ...
0
votes
1answer
87 views

What is the lyman-werner background?

I've seen several papers that discuss the Lyman-Werner Background (LWB) when modeling star and galaxy formation in the early universe. One in particular (https://arxiv.org/abs/1803.04527) even varies ...
2
votes
2answers
92 views

Has stellar evolution ever been modeled analytically?

I'll still remember the handout my astronomy professor gave us more than several decades ago; Our Friends the Polytropes. We spent a lot of time learning how polytropes, simple analytical power-law ...
4
votes
1answer
71 views

Why does the precession of the earth affect other planets?

In the Wikipedia article on numerical integration of planetary motion it states: ...the flattening of the Earth causes precession, which causes the axial tilt to change, which affects the long-...