Questions tagged [temperature]

Temperature is a measurement of the average kinetic energy of the molecules in an object or system. In simpler words: it's the degree or intensity of heat present in a substance or object that is commonly measured with a thermometer.

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Stellar temperature ~ frequency relationship?

According to Wikipedia, 76% of all stars are of spectral type M, 12% are of K, 7.5% are of G, etc. (see this section on Stellar Classification). This is very helpful, but is too vague, as the ...
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What is the history of the average pressure, density, and temperature of the matter in the universe over time?

This question is inspired by this more specific question where Cerelic wanted to know if conditions were suitable for liquid water to exist during an epoch when the characteristic temperature of the ...
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Could liquid water have existed in open space 15 million years after the Big Bang?

Around 15 million years after the Big Bang, the ambient temperatures was about $24^\circ {\rm C}$, which is in a range where water could be liquid. Could liquid blobs of water be existent then? PS: I ...
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Why temperature of dark side of moon is not 3 Kelvin

The temperature of the space between Earth and the Moon is around 3 Kelvin ($\approx -270^\circ {\rm C}$). The moon has no atmosphere, therefore the heat convection is not possible from the bright ...
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How would the temperature on earth be if the sun was slightly more or less powerful?

The temperature on earth is around 14C celsius. It is around 1370 W/m^2 from our sun. The earth has an albedo of around 0.3 On Tatooine (from Star Wars) i have been able to calculate it goes from 1066 ...
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How to accurately measure the temperature of red supergiants?

I just (February 28th, 2021) heard the news on progress how to measure the temperature of super giants: Red supergiants are a class of star that end their lives in supernova explosions. Their ...
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Why do degenerate objects get hotter as more mass is added?

After reading this question, I decided to post a question about degeneracy. I've seen simulations on large, $15\text{+ }M_J$ objects that are accreting mass. They do not grow in radius, instead they ...
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How do you refer to comparative temperature?

Earth's average surface temperature is about 288 K. If we had a hypothetical exoplanet with a surface temperature of 300 K, this would be about 4% higher than Earth's. Because we say Earth radii and ...
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What factors influence a star's temperature and density?

Assuming a relatively even proportion of mass and radius, a 0.25 solar mass and radius star would have a density of 22.5003 g/cm³, or about 16 times our Sun's density. However, there is obviously a ...
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How can I estimate how long will a main sequence star stay on the main sequence given its temperature?

I have a generic zero-age main sequence star. The only thing I know about it is its temperature. How can I estimate time time it spends on the main sequence (in millions of years)? I've seen equations ...
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Equilibrium Temperature for Extremely Cold Planets: Incorporating the CMB and Intrinsic Radiation

I want to check if I'm doing this right. I'm computing the equilibrium temperature for planets where the CMB and/or the planet's intrinsic radiation (as in weakly radiating jovians) matters. I start ...
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Exactly how long does it take for the exposed core of a star to cool from its starting temperature (several billion K) to ~50,000 K?

OK, I didn't know how I should word this question. But the basic point is that most white dwarfs that we have classified fall in temperature ranges from ~50,000 K to 6000 K. However, at the end of a ...
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What would the Earth's peri- and aphelion have to be in order to have the same seasons due to its orbit?

Imagine the Earth had no axial tilt but had seasons due to a very elliptical orbit. How elliptical would the Earth's orbit have to be in order to have about the same seasons as it has now (just with ...
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Is every single large solid body orbiting entirely outside of the frost line covered in ice?

Not sure where I heard that but I want to make sure if it's true. Forget about the asteroid belt for a minute: Are all the moons of the outer planets and kuiper belt objects covered in water ice?
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What is the coolest white dwarf known?

Okay, so in this ArXiv report from 2014, scientists discovered the coolest white dwarf, with a temperature of below 3000 K. However, as this report was from over 6 years ago, I think this information ...
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What units are used for the Stefan-Boltzmann law?

I have a star with given temperature in Kelvin and radius in solar radii. I tried to calculate the luminosity of the star using Stefan Boltzmann's law, and got an absurd number (over 1 million). What ...
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Blackbody curve in RGB for objects less than 1500 K?

We know the colors of stars that have a temperature greater than 1000-1500 K, shown here. However, I am wondering about those stars/brown dwarfs with surface temperatures of less than 1500 K. Is there ...
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What's the temperature of Pluto's core?

The surface is freezing-nitrogen cold, but it's typical for the temperature to increase towards the core. What's the temperature of the core of Pluto? Is the planet icy and rocky all the way through? ...
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What is the RGB curve for blackbodies?

I created a program to convert the temperature (in Kelvin) of a blackbody to RGB color. However, it is slightly inaccurate, and the deviations increase for values greater than 10000K and less than ...
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Can red dwarf stars have a spectral type of L?

We have the "normal" main sequence stars, OBAFGKM. Below K and M are the brown dwarfs, L,T, and Y. Zooming into the area at the edges of M and L, we have spectral types M9, M9.5, L0, and L1. ...
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What spectral type of star has an absolute magnitude of exactly 0?

We know that Vega is the star that serves as the zero point for the UBV color scale, and has an apparent magnitude of nearly zero (+0.02). But its absolute magnitude is +0.58, making it rather far ...
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Is there an O1 or O0 star?

Okay, we've seen the super hot Wolf-Rayet stars, especially WR 102 and 142, and the "slash stars," many of which are early O (O2-4.5/WN). We know the temperatures of these Wolf Rayet stars. ...
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How to calculate emission measure from EVE data? [closed]

I am trying to analyse solar flare temperatures from EVE FITS files in PYTHON. All I have are the irradiance values for a range of wavelength at every 10 seconds. I have made clear Gaussian fits to ...
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How to find the temperature of a planet accounting for the atmosphere?

Recently, I started writing a program to generate star systems, and I need a formula to find the approximate surface temperature of a planet. I know of several formulas for this, for example this one ...
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What is the average temperature of all planets at 1 bar?

Jupiter's (and Saturn's) "surface" temperature is defined as that at 1 bar. It is inconsistent to say the other planet's surface is their hard surface. Applying the same measure what is the ...
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How close would a Sunlike star have to be in order to be dangerous to look at it through a spyglass?

Alpha Centauri A which has an about 50% higher luminosity than the Sun is obviously undangerous to look at through a handheld telescope, at about 4.4 ly distance. How close would a yellow dwarf have ...
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What was the energy/wavelength/frequency of the CMB when first emitted/released?

Given the z redshift of 1089, and the temperature difference between then and now of about 1089, I tried scaling the ev, freq. and wavelength by 1089.... Is that right? I get a freq. of about 240 ...
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Will Jupiter eventually stop shrinking?

Jupiter is currently shrinking due to the Kelvin-Helmholtz mechanism. Will this mechanism eventually hold or getting slower? If so, at what size of Jupiter will it stop and why? If not, what will ...
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Would Europa be an ocean planet if it were in the habitable zone?

If a Europa-like body were in the Sun's habitable zone, let's say in an orbit between Earth and Mars, would the body become and remain a water ocean planet? In the habitable zone, the Sun would warm ...
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How does Io's atmosphere behave locally near volcanic plumes?

Io's surface air pressure is about $0.3 {\rm mPa}$ but Io's atmosphere is strongly variable, depending on whether it's on the near side or far side of Io (relative to Jupiter) and it collapses at ...
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How do I calculate the surface temperature of a star from luminosity? [duplicate]

How do I calculate the surface temperature of a star from luminosity? I've been trying to delve into speculative solar systems for a bit, and I've heard the surface temperature of a star can be ...
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Estimating star temperature

I have an assignment, where I'm supposed to estimate the temperature of a star in at least two different ways, and determine which of the approaches gives the most reliable estimate. All that is given ...
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What is the actual temperature of a quasar?

My daughter asked me last night: What is the hottest thing in the universe? The first thing that sprang to mind was the core of a fresh neutron star (this question agrees: What is the hottest thing ...
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Temperature of a substellar point on an airless tidally-locked planet

If a hypothetical blackbody planet's components were solid at all temperatures, would the substellar point on the airless tidally-locked (1:1) planet eventually heat up to the surface temperature of ...
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Relationship between Color Index and Temperature

Is there an exact relationship between color indices and temperature? I have seen some numerical formulas relating B - V color index to temperature, of the form $B - V = a_1 + \frac{a_2}{T} $ . I ...
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Finding the solar radius from temperature and luminosity

This question has eluded me for days; I can't seem to solve it. A certain star has a temperature twice that of the Sun and a luminosity 55 times greater than the solar value. What is its radius, in ...
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Estimating a star's radius, temperature, and luminosity based on its mass

(See updated figure and description below.) I've been trying to generate ballpark estimates for the radius, temperature and luminosity of stars in the main sequence based solely on their masses (...
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Why is Mars cold?

The surface temperatures of Mars are about -87C to 5C, which is much colder than that of Earth's. If Mars has 95% carbon dioxide, which is a Greenhouse gas, why is the surface of Mars so cold? ...
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Why is our Sun hotter than UY Scuti?

As Wikipedia says the surface temperature of UY Scuti is 3,365 K and the sun is 5,778 K Why is the Sun hotter than a supergiant star like UY Scuti?
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What if the atmosphere of Titan were like the one on Venus?

The current mean temperature in Titan is −180 ºC (93 K), the same as in Saturn. But I was wondering what would be the case if the atmosphere of Titan would be like the Venus atmosphere, whose ...
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Stars that don't fit $L=4\pi R^{2}\sigma T^{4}$?

When calculating luminosity/radius/temperature for several stars, I've noticed that while the majority of stars conform to the luminosity relationship $L=4\pi R^{2}\sigma T^{4}$, there are a few that ...
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Hottest Possible Hydrogen-Fusing Stars

I guess this is more a question about stellar models than anything else. I was wondering what is predicted to be the hottest possible stars that would still be hydrogen-burning. What complicates ...
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Do we know the fluctuations and constant temperature depth of the moon?

Disclaimer: I have no formal scientific training. From what I understand, surface temperature effects on Earth extend only so far into the ground so that at a certain depth the temperature remains ...
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What causes hot temperature extremes?

Recently I looked into the hottest(and coldest, but in another question) natural places. I find this to be a "cloud of searing gas that is surrounding a swarm of galaxies clustered together five ...
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What causes cold temperature extremes? [duplicate]

Recently I looked into the coldest(and hottest, but in another question) natural places. I discover this to be the Boomerang Nebula, with a freezing temperature of about −272.15 °C. Then I looked at ...
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Why would the Chang'e-4 lander find lunar far side temp. “colder than scientists expected”, when the LRO has already been taking thermal readings?

In January, the Chinese probe lander Chang'e-4 was was announced to have found temperatures dipping lower on the far side than expected ("Chinese rover finds lunar nights 'colder than expected'" by R. ...
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Regarding the VizierR catalogue

I want to build a Machine Learning model to approximate effective temperatures of stars based on their B-V index but there aren't that many catalogues that include that. I came across the Vizier ...
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Can Jupiter's nightside be classified as spectral type Y?

As far as I am aware, the latest spectral types that have been assigned are around Y2, for objects like WISE 0855-0714 that have temperatures around 250 K or so. I've also seen several directly-imaged ...
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How to Calculate Planetary Equilibrium Temperature in Binary systems

I'm working on a program that generates the basics stats of a terrestrial planets in binary star systems. I'm not the best at this kind of math, so I'm having trouble calculating the planetary ...
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How to Distinguish between Temperature and Doppler effect using Black-body radiation?

I understand that the radiation of a body can be described using the curve for black-body radiation. In the sense that a hotter body will be blue shifted and a cooler body will be red shifted. The ...