Young Black Hole

[dazed]

I just read about the discovery of a young black hole. It sems that in 1979 an amateur astronomy buff noticed a super nova and subsequent observations seem to show that a black hole was created there.

 

I was wondering what observations would be seen from this point on. I understand that the environment of the black hole will dictate the specifics, but is there a model for what to look for in the future from this object?

[Spyman]

I think astronomers will concentrate their observations to try to determine whether SN_1979C has formed a small Black Hole or a rapidly spinning Pulsar.

 

 

For people that want to read about the discovery, here are two links:

 

First compelling evidence for a black hole after recent supernova

Making use of archival data from the Chandra X-Ray Observatory, astronomers Daniel Patnaude, Avi Loeb and Christine Jones had a closer look at SN 1979C, a supernova in the galaxy M100. Earlier studies by Kasen and Bildsten (2010) and by Woosley (2010) suggested that SN 1979C, a "type IIL supernova", may have been powered by the birth of a magnetar – a neutron star with an extremely strong magnetic field. Observing a remarkably constant X-ray luminosity from supernova SN 1979 however, the authors propose that the late time glow of the supernova is more consistent with a stellar mass black hole accreting material from either a fallback disk or from a binary companion. They conclude that SN 1979C is likely to harbor a black hole with a mass five times that of the Sun. Furthermore, the black hole may be accreting matter from its surroundings or from a companion star.

http://www.eurekalert.org/pub_releases/2010-11/e-fce111710.php

 

 

Evidence Found for Youngest Black Hole Ever Seen

A cosmic explosion seen 31 years ago may have been the birth cry of the youngest black hole ever observed, which could help researchers understand how black holes are born and evolve.

 

Studying a baby black hole should also help astronomers understand what determines the fate of stars, as well as how common black holes are in our galaxy and throughout the universe, researchers said. [Photo of the baby black hole's location.]

 

"What's really exciting about it is we know the exact birth date of a black hole for the first time," Kim Weaver, of NASA's Goddard Space Flight Center, told reporters today (Nov. 15). "It's a wonderful opportunity for astronomers to look at these young systems."

http://www.space.com/scienceastronomy/youngest-nearby-black-hole-discovered-101115.html

[Spyman]

I also happened to stumble over this old article from 21 July 2005:

 

The supernova that just won't fade away

Using ESA’s XMM-Newton space observatory, a team of astronomers has discovered that this supernova, called SN 1979C, shows no sign of fading. The scientists can document a unique history of the star, both before and after the explosion, by studying rings of light left over from the blast, similar to counting rings in a tree trunk.

 

...

 

Supernovae can outshine an entire galaxy and are often easily seen in neighbouring galaxies with simple amateur telescopes. Supernovae are typically half as bright after about ten days and fade steadily after that, regardless of the wavelength.

 

SN 1979C has in fact faded in optical light by a factor of 250 becoming barely visible with a good amateur telescope. In X-rays, however, this supernova is still the brightest object in its host galaxy, M100, in the constellation ‘Coma Berenices’.

http://www.esa.int/esaSC/SEME2C0DU8E_index_0.html

 

IMHO, it's not far fetched that a newly formed Black Hole is feeding on material that was ejected by the star itself before it went supernova and are now falling back down upon it.

[Cygnus47]

About this subject; Young Black Holes................Can anyone here calculate the size of a ground state black hole? By ground state black hole, I'm referring to an event where a neutron star whilst feeding on a neighboring star continues to grow in mass until it reaches a density great enough for it to become a black hole. If this threshold can be reached without perturbation, I believe it would qualify as a new universal constant.....................Any thoughts????????

Edited August 14, 2011 by Cygnus47

[Realitycheck]

What happens to the protons in a neutron star and how are they situated in a black hole?

Edited August 14, 2011 by Realitycheck

[Cygnus47]

What happens to the protons in a neutron star and how are they situated in a black hole?

The protons are forced under the pressure to combine with other electrons resulting in the formation of more neutrons. As for the physics of the black hole, this is where classical understanding breaks down. According to present theory, the singularity has no constituent parts other than the singularity itself which manifests it's presence as only a gravitational influence. But this is only speculation at the present, we have no way of observing any information from inside the black hole and that will probably not change for a very long time. Some scientists are convinced we will never be able to see inside nor ever be able to prove one way or the other what lies within.

[Realitycheck]

Ahhh, thank you very much. All is revealed. I finally have a true understanding of the word singularity.

[csmyth3025]

About this subject; Young Black Holes................Can anyone here calculate the size of a ground state black hole? By ground state black hole, I'm referring to an event where a neutron star whilst feeding on a neighboring star continues to grow in mass until it reaches a density great enough for it to become a black hole. If this threshold can be reached without perturbation, I believe it would qualify as a new universal constant.....................Any thoughts????????

In general, compact stars of less than 1.44 solar masses – the Chandrasekhar limit – are white dwarfs, and above 2 to 3 solar masses (the Tolman–Oppenheimer–Volkoff limit), a quark star might be created; however, this is uncertain...

 

-and-

 

...In 2010, Paul Demorest and colleagues measured the mass of the millisecond pulsar PSR J1614–2230 to be 1.97±0.04 solar masses, using Shapiro delay.^[24] This is substantially higher than any other precisely measured neutron star mass (in the range 1.2-1.45 solar masses)...

(ref. http://en.wikipedia....i/Neutron_stars )

 

The fate of collapsed objects between 2 and 3 solar masses isn't entirely clear at this time. As far as I know, any collapsed object greater than 3 solar masses is thought to necessarily be a black hole.

 

Chris

[Cygnus47]

(ref. http://en.wikipedia....i/Neutron_stars )

 

The fate of collapsed objects between 2 and 3 solar masses isn't entirely clear at this time. As far as I know, any collapsed object greater than 3 solar masses is thought to necessarily be a black hole.

 

Chris

Thank you Chris,...............evidently, there remains much work to define more precisely this limit that I'm looking for. It is quite plausible that an exacting figure relative to baron count can establish the threshold responsible for this transition from, neutron or quark star, to black hole. It may be such a precise figure, discounting and or limiting any perturbations in the process, that it could be limited to as little as just a few neutrons or quarks. If and when this measure can be exactly defined, it may qualify as a universal constant.

 

There is another limit, commonly referred to as the "packing fraction". This has been theorized by some to have taken place shortly after the big bang resulting in the formation of mini black holes. If the Large Hadron Collider can recreate these conditions, we may be able to assign a value to this limit also. But this limit is distinctly different than the one I'm proposing. This limit is induced with the aid of external pressures and the one I am looking for is one that occurs only thru the natural compression of gravity.

 

I patiently wait for these results.................................

[Schrödinger's hat]

One confounding factor is angular momentum.

Neutron stars can spin so fast that the angular momentum can provide some (small) measure of support.

Naively I would think this would alter the mass required for black hole formation.

[Cygnus47]

One confounding factor is angular momentum.

Neutron stars can spin so fast that the angular momentum can provide some (small) measure of support.

Naively I would think this would alter the mass required for black hole formation.

Not so naive in my opinion Sch-hat, although one must also remember that the angular momentum at the equator is somewhat balanced by the flattening at the poles. Not sure exactly what the dynamics of this equal out to but it's obvious that this flattening at the poles will help reduce the effect of overall support against collapse.

 

Nevertheless, you make a very valid point sir.................................Good call!

Edited August 15, 2011 by Cygnus47

[MigL]

Look up Kerr ( rotating ) black hole. They still form black holes but have many interesting proprties.

 

The ambiguity as to the number of solar masses required for gravitational collapse to a black hole, is because stellar evolution is not completely understood. Before the collapse, to either neutron star or black hole, significant amounts of stellar material is blown off in the supernova explosion. If enough mass is blown off a 10 solar mass star it may only have enough remaining to form a neutron star. If not enough is blown off it may become a black hole. But the mass needed to form an event horizon is known exactly.

 

Incidentally, neutron stars continue to assimilate mass due to their gravitational force, especially if they are located in a gas or dust cloud. Eventually they reach the critical mass at which an event horizon is formed, but on the way there, they go supernova, Type Ia supernova, because conditions are pretty well identical for all type Ia supernova and their luminosity is a fixed figure. These are used as standard candels to determine intergalactic distances. They were recently used in the determination ( at the end of the last century ) that universal expansion is accelerating.

[Cygnus47]

Look up Kerr ( rotating ) black hole. They still form black holes but have many interesting proprties.

 

Incidentally, neutron stars continue to assimilate mass due to their gravitational force, especially if they are located in a gas or dust cloud. Eventually they reach the critical mass at which an event horizon is formed, but on the way there, they go supernova,

 

I don't understand. If this hypothetical neutron star reaches the critical mass at which an event horizon is formed, wouldn't that preclude a supernova event? When the last bit of matter is added to the total mass of the neutron star and the collapse takes place and the event horizon is formed, wouldn't the resulting black hole overcome any tendency toward ejecta? I was under the impression that neutron stars were stable, however I could be mistaken.

 

According to what you've told us, as the neutron star assimilates mass, it will reach a point where a singularity is formed. This suggests the formation of a black hole. But how could there be enough material left over for a supernova plus a black hole. I can understand one or the other but not both happening to this neutron star if we are only adding small amounts of mass at a time...........................Cygnus47

[imatfaal]

Look up Kerr ( rotating ) black hole. They still form black holes but have many interesting proprties.

 

The ambiguity as to the number of solar masses required for gravitational collapse to a black hole, is because stellar evolution is not completely understood. Before the collapse, to either neutron star or black hole, significant amounts of stellar material is blown off in the supernova explosion. If enough mass is blown off a 10 solar mass star it may only have enough remaining to form a neutron star. If not enough is blown off it may become a black hole. But the mass needed to form an event horizon is known exactly.

 

Incidentally, neutron stars continue to assimilate mass due to their gravitational force, especially if they are located in a gas or dust cloud. Eventually they reach the critical mass at which an event horizon is formed, but on the way there, they go supernova, Type Ia supernova, because conditions are pretty well identical for all type Ia supernova and their luminosity is a fixed figure. These are used as standard candels to determine intergalactic distances. They were recently used in the determination ( at the end of the last century ) that universal expansion is accelerating.

 

I thought Type 1a Supernovae were whitedwarves that were pushed over the limit by accretion of matter from a binary companion - ie no involvement of neutron stars. the neutron star is a fate of a whitedwarf that does not accrete any additional material. I cannot see how the neutron star would overcome its own gravity to explode nor what nuclear reaction would fuel it.

[Cygnus47]

I thought Type 1a Supernovae were whitedwarves that were pushed over the limit by accretion of matter from a binary companion - ie no involvement of neutron stars. the neutron star is a fate of a whitedwarf that does not accrete any additional material. I cannot see how the neutron star would overcome its own gravity to explode nor what nuclear reaction would fuel it.

I agree imatfaal...............I was under the impression that a neutron star, or quark star if that scenario is ever proven, was the last stage before gravitational collapse occurs leading to the formation of the singularity. I, like you, find it difficult to accept the notion that a neutron/quark star could escape collapse and suddenly go supernova. The question is; At what point in total mass will this neutron/quark star meet the threshold leading to black hole formation? There is a limit after which the last neutron being added to this body will initiate collapse. This is the limit I'm searching for................Cygnus47

[MigL]

Sorry got a little confused there and posted too quickly.

 

You are both right, it is white dwarfs that keep assimilating mass and upon reaching a specific limit ( Chandrachekar or about 1.4 sol mass ) collapse to become neutron stars. The gravitational collapse, subsequent heating and bounce leads to a 'standard' supernova.

[csmyth3025]

...But the mass needed to form an event horizon is known exactly...

As far as I know, your statement is true - provided that you know the exact volume in which the mass is contained.

 

The Schwarzschild radius of an object is proportional to the mass. Accordingly, the Sun has a Schwarzschild radius of approximately 3.0 km (1.86 miles) while the Earth's is only about 9.0 mm, the size of a peanut. The observable universe's mass has Schwarzschild radius of approximately 10 billion light years.

(ref. http://en.wikipedia....rzschild_radius )

 

Chris

 

Edited to improve readability.

Edited August 20, 2011 by csmyth3025

[Cygnus47]

As far as I know, your statement is true - provided that you know the exact volume in which the mass is contained.

 

True, ................the Schwarschild radius formula is: ro=2GMo/c^2

 

This describes the radius and mass compaction a body must achieve before escape velocity reaches the speed of light. In the case of the neutron/quark star, the strong nuclear force must be overcome to reach this compaction fraction. My question is; at what point does the neutron/quark star reach this threshold? Put another way; How large must the neutron/quark star become before collapse takes place?

[MigL]

You are right the event horizon is defined in terms of mass and radius. However a non radiating collection of critical mass, has no counter to gravitational force, such as a 3-4 solar mass object compose of iron.

It doesn't matter what its radius is, it will collapse to form a black hole if its mass is above the critical limit ( it'll just take a little longer to form a horizon ).

The radius of its eventual event horizon will be given by the mentioned formula.

[csmyth3025]

True, ................the Schwarschild radius formula is: ro=2GMo/c^2

 

This describes the radius and mass compaction a body must achieve before escape velocity reaches the speed of light. In the case of the neutron/quark star, the strong nuclear force must be overcome to reach this compaction fraction. My question is; at what point does the neutron/quark star reach this threshold? Put another way; How large must the neutron/quark star become before collapse takes place?

 

Maximum Mass, Minimum Period

Theoretical limits from GR and causality

Mmax = 4.2(ǫs/ǫ0)1/2 M⊙

Rhoades & Ruffini (1974), Hartle (1978)

Rmin = 2.9GM/c2 = 4.3(M/M⊙) km

Lindblom (1984), Glendenning (1992), Koranda, Stergioulas & Friedman (1997)

ǫc < 4.5 × 1015(M⊙/Mlargest)2 g cm−3

Lattimer & Prakash (2005)

The above partially quoted table is taken from : Neutron Star Equations of State by James M. Lattimer (pdf pg 6) which can be found here:

http://www.ns-grb.com/PPT/Lattimer.pdf

The most massive precisely measured neutron star is J1614-2230 - it's about 2 solar masses:

In 2010, Paul Demorest and colleagues measured the mass of the millisecond pulsar PSR J16142230 to be 1.97±0.04 solar masses, using Shapiro delay.^[24] This is substantially higher than any other precisely measured neutron star mass (in the range 1.2-1.45 solar masses), and places strong constraints on the interior composition of neutron stars.

(ref. http://en.wikipedia...._of_discoveries )

 

The above formula tells me that the minimum radius of a two solar mass neutron star would be about 8.6 km, a three solar mass neutron star would be about 12.9 km, and a 4 solar mass neutron star would be about 17.2 km.

It seems pretty certain that a two solar mass neutron star can exist. Beyond that, I'm not sure anyone can say exactly what the limit is. The formula for maximum mass seems to provide an answer, but I don't know what Qs and Q0 are.

Chris

PS - sorry about the stretched-out lay-out. Copying the pdf format table seems to have messed up the coding in this post.

Edited to correct spelling errors

 

Edited August 21, 2011 by csmyth3025

[csmyth3025]

The most massive precisely measured neutron star is J1614-2230 - it's about 2 solar masses:

In 2010, Paul Demorest and colleagues measured the mass of the millisecond pulsar PSR J1614–2230 to be 1.97±0.04 solar masses, using Shapiro delay.^[24] This is substantially higher than any other precisely measured neutron star mass (in the range 1.2-1.45 solar masses), and places strong constraints on the interior composition of neutron stars.

 

(ref. http://en.wikipedia...._of_discoveries )

 

Chris

PS - sorry about the stretched-out lay-out. Copying the pdf format table seems to have messed up the coding in this post.

I re-quoted the above passage - which seems to have been garbled by the coding conflicts in my original post.

Chris