# All Questions

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### Magnetic fields of peculiar HgMn A type stars

Do HgMn (peculiar A type) stars really possess global magnetic fields? See, for example, this paper by Hubrig et al. from 2012.
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### Can there be an object with planetary discriminant between Ceres and Neptune?

The planetary discriminant is a measure of how dominant a body is within its region of the solar system. For (true) planets, it is >10000 and for dwarf planets it is <1. See this answer for more ...
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### Equation for solar radiation at a given latitude on a given exoplanet?

I'm trying to find equations that would help me determine the amount of solar radiation hitting a certain latitude on a certain planet given the following inputs: the degrees of latitude of the ...
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### Orbits in a binary star system

I know of three sets of stable orbits in a binary star system: orbiting closely around star A, orbiting closely around star B, or orbiting distantly around both stars (and their mutual center of ...
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### Does CIBER Experiment from Caltech suggest that there can be lots of stars which are not in any galaxy?

My question is about the implications of the observations recently made by the Cosmic Infrared Background Experiment, or CIBER, from Caltech. I've read at Caltech web site: "The total light ...
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### What implications does younger volcanism have on the Moon's thermal evolution?

In the paper Evidence for basaltic volcanism on the Moon within the past 100 million years (Braden et al. 2014), suggest that features such as Ina (image below) represent a far more recent age of ...
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### Rings around a smaller, close-in planet?

Is it possible for a small, close-to-star planet to have a stable ring system--icy or otherwise? A smaller planet means the rings would have to be closer to the planet, which means the radial shear ...
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### Are we sure no planets inside Mercury orbit now?

Currently most explorations about new planets are pointing to area outside Neptune orbit, how about inside Mercury orbit? Can we say there is no planets inside Mercury orbit surely?
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### What visual artifacts are expected from the JWST?

What visual artifacts should we expect from the images that will be released from the James Webb Space Telescope? Specifically, do we expect 3-pronged diffraction spikes (any preview how they would ...
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### Does the shape of a supernova remnant depend on the progenitor star's magnetic field?

The magnetic field activity in a star can be very chaotic and my question is are they somehow related?
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Regarding solar system dynamics, i.e. planets in stellar systems and moons in planetary systems, this is often mentioned in the literature, but it is difficult to find a good analysis/explanation of ...
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### Are trojans in L5 more likely than in L4?

Mars has much more trojans in L5. Does it reflect a common pattern?
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### How can you determine the initial volume of a planet's atmosphere?

Since the surface pressure of a planet is determined by the mass of the column of gasses above it one would surmise that to determine the pressure you must know the volume and mass of the atmosphere. ...
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### Questions about a fictional binary system, and habitability

Note: Questions are at the bottom. The rest had simply been written in a format to better organize my thoughts. The formulas used to construct this fictional solar system, had been borrowed from ...
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### What is the cause of the variation from high and low mean obliquity periods of Mars?

It is reasonably well known that Mars has a greater obliquity range than Earth, due to Mars lacking a stabilising influence of a large moon. However, the Martian obliquity seems to have gone through ...
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### 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 ...
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### Does the radius of the Universe correspond to its total entropy?

I heard a claim that due to holographic principle, the surface area of the cosmic horizon corresponds to the universe's total entropy. As such the initial state had zero surface area and later ...
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### Simulate an orbit with orbital elements

I want to simulate the orbits of the planets from our solar system. I want to use orbital elements to calculate the current position(xyz) at a time t. The simulation doesn't have to be too exact, but ...
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### Is there an upper limit to the mass of terrestrial planets

The exo-planet Kepler-10c has a mass between 15 and 19 times the mass of the Earth (making it comparable in mass to Neptune), and yet is thought to have a density of about 7g/cm^3 and to be a ...
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### How bright can white dwarf stars glow as they accrue matter?

I realize this is kind of general as it would depend on the size of the white dwarf and the rate of accrual. The general idea I got thinking about is what would happen if a white dwarf star - lets ...
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### Is extraterrestrial mining more difficult for bodies without plate tectonics?

This article talks about the possibility of mining Uranium on the moon. Since the Moon lacks the geological forces that have created veins of concentrated minerals on Earth, would extraterrestrial ...
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### What's the bleeding-edge model for how Population III stars are born and evolve?

I'm trying to do a brief literature review to find out what the best current models for population III stellar evolution are. I was hoping that someone with more expertise in the area could perhaps ...
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### 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 ...
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### Has New Horizon's data updated Charon's orbital elements?

For years I've been fascinated with the mutually tide-locked bodies Pluto and Charon. In July 2012, The Astronomical Journal published an article The Orbit of Charon Is Circular by Buie, Tholen and ...
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### How thick can planetary rings be?

This arose from a comment on Worldbuilding. We have data from four planets in the Solar System with rings, which doesn't make for a very good sample size. Observations of exoplanets could change ...
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### How does one find the extinction coefficient of a particular galaxy?

I am doing photometry on a number of objects in a number of different galaxies. I need the extinction coefficients for these galaxies for various filters passes. Is there some database that displays ...
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### Formation and capture of Mars' moons, Phobos and Deimos

Mars's moons have the appearance of captured asteroids. How could this capture have taken place. An asteroid in solar orbit would need to loose some momentum to be captured. The gas Giants can ...
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### Does Mars contain more iron than the Earth?

Is the reason Mars is red because its surface contains a lot of iron? (When dirt is red on Earth, it is sometimes caused by a high amount of iron). If so, does Mars contain more iron than the earth? ...
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### Moving from computerised to normal amateur telescope?

A few years ago I purchased a Celestron Nexstar 130 SLT computerised telescope thinking that it would be a perfect to get me into astronomy. The issue is the computer doesn't work at all and manually ...