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Unanswered Questions

11
votes
1answer
257 views

The battle over Gliese 581 and Gliese 667C?

In 2014, Robertson et al. made a case that stellar activity is masquerading as planets (here and here) for these well-known systems. In both cases, they claim that the only real planets discovered so ...
10
votes
0answers
272 views

Terrestrial Exoplanet Skies – I've Built a Visual Sky Chart. Is it Accurate?

I'm an artist (and science enthusiast) and I've been trying to find a comprehensive resource that would help me clearly identify likely sky colors (as perceived by human vision) for exoplanets that ...
9
votes
0answers
271 views

Is it “weird” that all disc galaxies rotate once every billion years?

In a recent paper (Cosmic clocks: A Tight Radius - Velocity Relationship for HI-Selected Galaxies by Meurer, et al.), it was noted in the conclusion that: [This] implies a constant orbital time of ∼...
8
votes
0answers
394 views

How to determine scalar-to-tensor ratio r from CMB polarization spectrum?

CMB polarization spectrum can tell us about the primordial scalar and tensor perturbation. By analyze B and E mode angular spectrum power spectrum and temperature power spectrum we can determine the ...
7
votes
2answers
162 views

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

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
votes
0answers
138 views

Since when are we able to discover interstellar objects similar to 1I/ʻOumuamua?

Since when are our observation capabilities good enough to discover objects similar to the first discovered interstellar object 1I/ʻOumuamua (October 2017) with high probability? Could we make rough ...
7
votes
0answers
317 views

Python 2D Jean Instability in Spiral Galaxy Simulation

I have ~1000 snapshots of a spiral galaxy simulation (from Molecular cloud perturbations t=0 to t>1Gyr. What I need to do is determine whether any position at any of the snapshot times meets criteria ...
7
votes
1answer
156 views

Sedna, VP113 and the likelihood of the PX/Tyche/Thelistos hypotheses

Crosslisted question from https://physics.stackexchange.com/questions/131876/sedna-vp113-and-the-likelihood-of-the-px-tyche-thelistos-hypotheses The recent discoveries in exoplanetary science (...
7
votes
0answers
82 views

Estimating the tangential and cross component of the galaxy's shear using Gnomonic projection

I would like to know how I can estimate the tangential and cross component of the galaxy's shear using Gnomonic projection of the right ascension and declination ...
6
votes
0answers
153 views

What is the limiting abundances of elements at the end of the stelliferous era?

Is there any reputable published source on expected elemental abundances at the end of the era of stellar fusion? I am here interested in the contents of galaxies; much of intergalactic gas will be ...
6
votes
0answers
70 views

Error propagation methods for orbit parameters

Recently I've encountered an article in our local astronomical popularization magazine. It is about a well known task of Sgr A*-black hole's mass estimation. The article is written as a step by step ...
6
votes
0answers
130 views

Planning to revisit Arthur Eddington's experiment from 1919

As the fateful day draws closer, the United States will host a celestial event that comes once in three generations. I plan to witness this first hand at the exact center of greatest eclipse. In the ...
6
votes
0answers
56 views

How can maser emission be unpolarized?

I was reading that: However, unlike Galactic sources such as W3(OH), the emission is unpolarized and the 1667 MHz line is stronger than the 1665 MHz line. but how is this possible? Does not the ...
6
votes
0answers
354 views

Horseshoe orbits and integration in C

I'm studying a particular case of the restricted three-body problem. It's been found that some objects follow a horseshoe orbit pattern, and I'm trying to sort out something through an integration ...
6
votes
0answers
48 views

Has the Kepler data been examined for light curves due to phase changes of non-transitting hot Jupiters and other?

I found this article http://www.epj-conferences.org/articles/epjconf/pdf/2011/01/epjconf_ohp2010_03005.pdf from 2011 announcing that two dozen secondary eclipses of "hot Jupters" have been seen in ...

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