# What is Solar mass: Definition and 14 Discussions

The solar mass (M☉) is a standard unit of mass in astronomy, equal to approximately 2×1030 kg. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass of the Sun. This equates to about two nonillion (short scale) or two quintillion (long scale) kilograms:

M☉ = (1.98847±0.00007)×1030 kgThe solar mass is about 333000 times the mass of Earth (M⊕), or 1047 times the mass of Jupiter (MJ).

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1. ### B Understanding the Stress-Energy Tensor & Solar Mass in General Relativity

In the test of General Relativity by perihelion motion of mercury, the stress-energy tensor is set to 0 in Schwarzschild solution. Then, is the curvature caused by solar mass, or by the 0 stress-energy? Or, do we consider solar mass as the gravitating mass? Or the 0 stress-energy the gravitating...
2. ### B Rest Energy and a 1 million solar mass black hole

Suppose there is a 1 million solar mass black hole. A 1.022MeV photon near a nucleus produces an electron-positron pair a distance=A from the event horizon. The positron’s vector is directly “up” away from the singularity. It doesn’t have escape velocity. It reaches an apogee at distance=B from...
3. ### Calculating Solar Mass using peak Doppler shifts

Homework Statement Imagine two planets orbiting a star with orbits edge-on to the Earth. The peak Doppler shift for each 70 m/s, but one has a period of 7 days and the other has a period of 700 days. The star has a mass of one solar mass. (Assume 1 solar mass equals 2E+30 kg.) Q1: Calculate...
4. ### I Computing a value of radius for a typical white dwarf

I try to get a correct result for the radius of a standard white dwark (roughly 10000 km). I just want the order of magnitude , i.e with the common values of a solar mass into Earth radius sphere. From http://www.astro.umontreal.ca/~bergeron/CoolingModels/Synthetic_Calibration.pdf page 1223...
5. ### Help needed interpreting the speed of an asteroid

Homework Statement A asteroid is hurtling towards Earth and humankind has decided to fire a nuclear warhead at it in order to avert disaster. In order be most effective the rocket carrying the warhead has to impact the asteroid at 40km/s. The rocket itself travels at 12km/s. What remains is to...
6. ### Using Eddington Luminosity to calculate mass

Homework Statement The nuclear reactions in a star’s core are very sensitive to pressure and temperature, so high mass stars have much higher luminosities. The luminosities of massive stars have been observed to obey the following scaling relationship with mass (M): Lstar = (34.2)*M^2.4...
7. ### BH to Sun, back of the napkin calculation of solar mass

Yesterday I had a bizarre idea. I supposed that a black hole (which I assumed to be a sufficiently dense sphere) became our sun. I know this is completely wrong, but please humor me and see what I've done. Suppose we have a sphere sufficiently dense, so that the Schwarzschild radius, r_s, is...
8. ### The mass of the sun at its beginning

Hi guys, so I know the sun is losing mass because it is radiating energy away. This leads me to wonder about some things - I have been trying to figure out what the mass of the sun was ~4.5 billion years ago (current age of the sun). Also I am interested in knowing what the mass will be ~6.5...
9. ### Is There a 100 Solar Mass Black Hole in Orion Nebula?

This paper proposes a 100 solar mass black hole in nearby Orion Nebula: http://arxiv.org/abs/1209.2114 Exciting if true. I have no particular comments, just thought it should be noted here.
10. ### Energy Generation Coefficient in a 50 Solar mass Main Sequence star

Homework Statement Calculate the energy generation coefficient ε (J s^-s kg^-1) in the center of a 50 Solar mass Main Sequence star, assuming that all luminosity is generated in a constant density core containing one tenth of the total mass of the star. Homework Equations L=M^3.3...
11. ### Astronomy, Luminosity of 100 solar mass stars

This is just a small part of one of my problems. I need to find the luminosity of a stellar population containing 100 solar mass stars and one 20 solar mass star. I think that the 20 solar mass star will dominate, but I am not sure. Here is the formula to use: L/Lsun = (M/Msun)^3.5 I...
12. ### Estimate the radius of a solar mass black hole.

Estimate the radius of a solar mass (2 × 1030 kg) black hole. How do I do it? I have literally no idea! Thanks in advance for any help.
13. ### How Do Astrophysicists Measure Solar Mass Loss?

From nuclear theory and texts its known that every second 570 millions tons of hydrogen are converted to 566 millton hellium,hence Sun loss 4 mill tons of mass in a second. But ¿how do astrophicisist probe experimentally this number?,have they measured solar gravity field or Earth atraction...
14. ### Calculating solar mass using luminosity

Okie dokie, I searched the web and found L=M ^ 3.5 (luminosity equals mass to the power of 3.5). But, I'm pretty clueless on anything beyond Algebra I. How do I solve for M if I know L? [If the answer can be expressed in Visual Basic syntax, all the better.] I also read several caveats...