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Questions tagged [mass]

Questions regarding the property of astronomical objects that determines their inertial resistance and gravitational interaction with other bodies.

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20 views

If we've only observed Oumuamua as a single pixel, how can we know its shape?

On a separate Oumuamua question (Oumuamua alien space junk?), I was confused how shape could be inferred from a single pixel, per another user's (@Uwe) comment. It was suggested I ask this question ...
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269 views

How would I define mass in a space

I always heard that mass is a measure of inertia during my school days. Is this applicable to bodies which are in space ? Suppose there is space craft in a space; how would I define mass ? I read ...
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58 views

Existence of a mass-volume astronomical chart?

I've been wanting to make a mass-volume (or mass-radius) chart for astronomical objects ranging from asteroids to supermassive black holes on a log-log scale. A sort of 'Hertzsprung-Russel' type ...
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165 views

How to determine the mass of a galaxy?

I am having a slight disagreement with my professor. We can measure the mass of a distant star cluster from: A.Its color B.Its radius C.Its metallicity D.Smearing of lines in ...
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1answer
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How did they estimate the mass of Sgr A*'s companion G2 without knowing what it was?

Gizmodo.com's Astronomers Spot Unprecedented Flashes From Our Galaxy's Black Hole mentions Sgr A*'s companion gas cloud G2. That Wikipedia article says: First noticed as something unusual in ...
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122 views

Could anything consume a small black hole?

Whenever I read about black holes, it is normally involving how they devour anything that comes too close... regardless of how big anything is. But what if it were a really small black hole vs ...
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2answers
99 views

Black hole's gravity

Is gravity relative to volume, or size of an object? Since a black hole is a massive star that collapses on its weight, how comes the same sun's mass, when it becomes a black hole, provides gravity ...
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44 views

I need help with an equation for figuring out the surface temperature of Red Dwarf!

Say you have a 10 billion year old, slow rotating, quiescent M5 star with a mass of 0.32 M☉ , a luminosity of 0.018 L☉ and a burning (haha) desire to figure out the surface temperature. However you ...
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33 views

Roche lobe - flow of mass

In which situation can smaller star in binary fill the Roche lobe? When flow mass of smaller star to larger star? Smaller star fill the Roche lobe in Algol paradox. Does the mass of smaller star ...
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1answer
31 views

Comet mass loss

As the comet orbits around the Sun, I gather that its tail loses mass due to solar wind and tidal waves. Approximately, from what distance (with respect to Sun) will the mass loss begin?
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53 views

How is stellar mass of a galaxy obtained?

I believe there is a difference between the mass calculated using the orbital speed and the stellar mass of the galaxy. So how is the stellar mass calculated? Thank you :)
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Mass of Photon and Black holes [duplicate]

The gravity caused by a black hole is said to be so strong such that even light(photons) can not escape from it. since gravity exist only in between objects with mass, How does a black hole attract a ...
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241 views

Is blue light not traveling faster then red light in space?

I just can't understand why light and other massless particles are not traveling at different speeds? Gravity effects anything with a mass but light has no mass but a black hole, and weak lensing ...
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1answer
69 views

What does it mean when there are two plus-or-minus signs for a measurement?

As far as I know, the plus-or-minus sign is used to indicate the statistical margin of error of a measurement. But what does it mean when there are two plus-or-minus signs in the same measurement? ...
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868 views

How do I create a galaxy stellar mass function?

Suppose that I have an array of stellar masses of tens of thousands of galaxies, and that I also already know what the total "survey volume" is (in Mpc^3) within which all of those galaxies are ...
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53 views

Mass of a potential black hole in a binary system

So I've been given the velocity curve, parallax and apparent magnitude of a star in a binary system with what is potentially a black hole. I've calculated from the apparent magnitude and parallax that ...
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1answer
138 views

Smallest mass of star to be a black hole? [duplicate]

It seems to me that I forgot the smallest mass of a star and its angular momentum in order to form a black hole. So I know that electron degeneracy pressure is overcome if the core is 1.4 solar ...
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1answer
349 views

What type of energy is escaping from black-hole's poles?

Following this article, it is stated that: As a star drifts too close to a supermassive black hole, intense tidal stresses rip the star to shreds. As this happens, the shredded material will ...
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1answer
104 views

Does the Sun twinkle?

Does our solar system have enough bodies in orbit to appear to twinkle to another distant solar system viewed from the side? https://en.wikipedia.org/wiki/List_of_asteroid-discovering_observatories ...
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What is the minimum mass required so that objects become spherical due to its own gravity?

Is this minimum mass known? or maybe, is it given in terms of density? If so, how much density is the minimum to have an spherical object due to its own gravity?
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229 views

How does the size of a naked black hole effect its photon sphere?

What effect does the size of a black hole have on the size or density of the photon sphere and it's proximity to the horizon? For example: A person is in space looking at 2 black holes, one of them ...
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109 views

Need help with a simple Blackhole question

Suppose the amount of mass in a black hole doubles. Does the event horizon change? If so, how much does it change?
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Doppler Spectroscopy - Finding mass of an exoplanet

An astronomer, T observed the spectrum of a distant star X. The spectral lines were observed to have tiny blueshifts and redshifts regularly with a period of 1.27 years. T concluded that the star is ...
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1answer
280 views

Why the Sun-Jupiter barycentre is outside Sun?

The Earth-Moon barycentre is said to be inside Earth. But Moon-Earth mass ratio (1.2%) is larger than Jupiter-Sun mass ratio (0.09%). Then how come the Jupiter-Sun barycentre is outside the surface of ...
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648 views

Is there a flaw with the newer purposes and correlations attributed to the HR diagram? (And would a third axis of mass correct the enclosed flaw?)

When I was younger, I was looking at HR diagrams, and began to experiment with the HR diagram. I was looking at plotting different groups of stars on the HR diagram when I found RV Tauri stars. ...
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2answers
112 views

Galactic mass estimation from apparent magnitude and distance

Can we estimate the order of the total mass of any galaxy from the apparent magnitude and its distance to us? Just like \begin{equation} M_{galaxy}=c\times 10^{8}M_{\odot }, \end{equation} where $c$ ...
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Compute the total stellar mass of galaxy with major influence of Red Giants luminosity

Suppose that all stars in this galaxy were born in a single major-merger burst event about 10 Gyr ago If the luminosity in the B band (absolute magnitude in B-band is equal to -21.22) is dominated by ...
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2answers
786 views

Are there upper or lower mass limits for black holes?

Natarajan & Treister (2008) describes a practical upper limit for black hole masses at $\sim 10^{10} M_\odot$. This is all due to the black hole's interactions with nearby matter. However, is ...
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1answer
56 views

How can I estimate the M/L ratio from a fitted SED on a galaxy?

This answer (here in the forum) provides background to my question: https://astronomy.stackexchange.com/a/5953 I am trying to understand the process in which a stellar population synthesis (SPS) is ...
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1answer
3k views

Are planets moving away from the sun?

I saw on the tv show Through the Wormhole (hosted by Morgan Freeman) that the planets in our solar system have been continuously moving away from the sun for millions of years. however, when I try to ...
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2answers
838 views

Why do certain massive stars leave no remnants?

Mass and metallicity are the two main determinants for a star's fate. This is simple enough. What's more complicated is how exactly these determine the star's fate. For example, you can see in this ...
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2answers
154 views

Does the mass of a collapsing star change?

Does a star, when collapsing into a neutron star, or even a black hole, pick up any significant relativistic mass due to its rapid collapse rate?
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1answer
60 views

How come moon's difference in thickness between sides does not create an unbalance on its mass?

I've just found out that moon's dark side is 30 miles thicker then the closer side to the Earth. So I'm wondering about moon's mass. How come it's still balanced? Supposing the far side is indeed ...
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249 views

Can “rogue” supermassive black holes be made this way?

Could two galaxies (one big and one small)intersect at a velocity to allow the smaller black hole to escape but not the galaxy around it?
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1answer
2k views

If an object with mass were to somehow go the speed of light, would it destroy the whole universe? [closed]

Would an object with mass traveling the speed of light destroy the whole universe because it would have infinite energy / mass? According to wikipedia and other sources, it takes infinite energy to ...
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1answer
69 views

Mass-magnitude relation of evolved stars

In short: what mass is appropriate for absolute magnitude $M_V \sim -7$? Some context: I'm processing the observational data (supernova light curve) and curve fitting gives me about $0.4M_\bigodot$ ...
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388 views

How does space time differ between galaxies? [duplicate]

Does the gravity wells differ enough between galaxies to have different speeds in space time? How much slower in space time would the biggest galaxy have compared to the Milky Way?
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1answer
253 views

Is Earth losing orbit? [duplicate]

Is the Earth losing or gaining distance from the sun overall? Could asteroids over time add weight to the Earth and push it farther from the sun more than having a degrading orbit around the sun? Does ...
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3answers
311 views

Why are black holes that massive?

Today known most massive star, R136a1 weighs approximately 256 times the mass of our sun, how did supermassive black holes, with a mass of 10 billion times the sun form? I understand, that when a ...
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1answer
54 views

Relation between molecular cloud mass and galactic mass

Would it be true to assume that the mass of a galaxy is approximately the mass of all molecular clouds detected within it, let's say, through CO observations and then converted to H$_2$?
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2answers
193 views

Circular velocity in axisymmetrici potential [duplicate]

If a matter distribution is spherically symmetric, the circular velocity is straightforwardly related to the mass via: $v_{circ} = \sqrt{GM/r}$ In an axisymmetric potential, on the other hand hand, ...
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431 views

How is the total mass of all the Solar System's small asteroids and meteoroids estimated?

This diagram from wikipedia (shown below) graphs asteroid Diameter against Number of asteroids, for the Solar System. (Graphic is courtesy of the Marco Colombo, DensityDesign Research Lab). ...
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Pluto is fuzed to all the asteroids, comets, other minor planets, etc. Would it be big enough to hold an atmosphere without forming a tail? [closed]

Pluto is fuzed to all the asteroids, comets, other minor planets, etc. Would it be big enough to hold an atmosphere without forming a tail? All minor planets, asteroids, comets, etc that aren't ...
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Size and Mass of a typical “small” asteroid that impacts the Earth?

I'm looking for some realistic data about the size (in meters) and mass (in kg) of a typical small asteroids that impact the Earth, without disintegrating in the atmosphere. Any suggestion ?
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616 views

Stellar mass limits for Neutron Star and Black Holes

Don't hate on me if I am asking a very basic and straightforward thing. I have a few questions about black holes and neutron stars. What is the mass range (in terms of solar masses) for a main ...
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1answer
946 views

Sum of the Masses of All Moons in the Solar System

I'm looking for the total mass of the moons in the solar system in Earth Mass this would be include the 67's moons of jupiter, the 62's of saturn, the 27's Uranus and the 14's for Neptune. it's a ...
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2answers
2k views

Does the event horizon of a black hole increase or decrease by adding mass?

So a black hole is a something that has enormous gravity, therefore mass accelerates faster towards it. But if the black hole double it's mass, will it's event horizon increase in length , or will it ...
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116 views

What IS HD 106906b?

Until recently, it was thought that should the size of Jupiter exceed 86,881.4 miles in diameter or the mass 318 times greater than Earth's, it would become a dwarf star, not a planet. WASP-17b is ...
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790 views

Mass of black holes compared to parent star

What is the range of percentage mass of parent star left in a stellar black hole directly after its formation? What factors determine this number for a specific case?
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1answer
297 views

Rewriting the equation for the virial mass of a cluster

I have a question that I don't know how to solve, any help is appreciated. Here it is: Rewrite the equation for the virial mass of a cluster so that if velocities are entered in km/sec and ...