New star described in a model combining relativity and quantum mechanics

March 9, 2018, International School of Advanced Studies (SISSA)
Credit: CC0 Public Domain

A new kind of star is reported in a study by SISSA postdoctoral researcher Raúl Carballo-Rubio. In a paper recently published in Physical Review Letters, Carballo-Rubio describes a novel mathematical model combining general relativity with the repulsive effect of quantum vacuum polarization. The result is a description of an ultra-compact configuration of stars that scientists previously believed did not exist in equilibrium.

"As a consequence of the attractive and repulsive forces at play, a massive star can either become a neutron star, or turn into a black hole" says Carballo-Rubio. In neutron stars, stellar is the result of the balance between gravity, an attractive force, and a quantum mechanical repulsive force called degeneracy pressure. "But if the star's mass becomes higher than a certain threshold, about three times the solar mass, the equilibrium would be broken and the star collapses due to the overwhelming pull of the gravitational force."

In the study, Carballo-Rubio investigated the possibility that additional quantum mechanical forces expected to be present in nature permit new equilibrium configurations for stars above this threshold. The additional force is a manifestation of the quantum vacuum polarization effect, which is a robust consequence of mixing gravity and mechanics in a semiclassical framework. "The novelty in this analysis is that, for the first time, all these ingredients have been assembled in a fully consistent model. Moreover, it has been shown that there exist new stellar configurations, and that these can be described in a surprisingly simple manner."

There are still several important issues that remain to be studied, including the observational applications of these results. "It is not clear yet whether these configurations can be dynamically realized in astrophysical scenarios, or how long would they last if this is the case." From an observational perspective, these "semiclassical relativistic stars" would be very similar to . However, even minute differences would be perceptible in the next generation of gravitational wave observatories: "If there are very dense and ultracompact in the Universe, similar to black holes but with no horizons, it should be possible to detect them in the next decades."

Explore further: A better way to model stellar explosions

More information: Raúl Carballo-Rubio, Stellar Equilibrium in Semiclassical Gravity, Physical Review Letters (2018). DOI: 10.1103/PhysRevLett.120.061102

Related Stories

A better way to model stellar explosions

March 5, 2018

Neutron stars consist of the densest form of matter known: a neutron star the size of Los Angeles can weigh twice as much as our sun. Astrophysicists don't fully understand how matter behaves under these crushing densities, ...

Supermassive black holes can feast on one star per year

February 1, 2018

CU Boulder researchers have discovered a mechanism that explains the persistence of asymmetrical stellar clusters surrounding supermassive black holes in some galaxies and suggests that during post-galactic merger periods, ...

How massive can neutron stars be?

January 16, 2018

Astrophysicists at Goethe University Frankfurt set a new limit for the maximum mass of neutron stars: They cannot exceed 2.16 solar masses.

What are neutron stars?

October 16, 2017

Thrilled physicists and astronomers announced Monday the first-ever observation of the merger of two neutron stars, one of the most spectacularly violent phenomena in the Universe.

Recommended for you

Jupiter's moon count reaches 79, including tiny 'oddball'

July 17, 2018

Twelve new moons orbiting Jupiter have been found—11 "normal" outer moons, and one that they're calling an "oddball." This brings Jupiter's total number of known moons to a whopping 79—the most of any planet in our Solar ...

Astronomers find a famous exoplanet's doppelgänger

July 17, 2018

When it comes to extrasolar planets, appearances can be deceiving. Astronomers have imaged a new planet, and it appears nearly identical to one of the best studied gas-giant planets. But this doppelgänger differs in one ...

Dawn mission to gather more data in home stretch

July 17, 2018

As NASA's Dawn spacecraft prepares to wrap up its groundbreaking 11-year mission, which has included two successful extended missions at Ceres, it will continue to explore—collecting images and other data.

Brown dwarf detected in the CoRoT-20 system

July 16, 2018

An international group of astronomers has discovered a new substellar object in the planetary system CoRoT-20. The newly identified object was classified as a brown dwarf due to its mass, which is greater than that of the ...

6 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

cantdrive85
2.4 / 5 (5) Mar 11, 2018
Nevermind the fact that relativity and QM are incompatible.
poisonoak
2 / 5 (4) Mar 11, 2018
Increasing disturbing trend at phys.org and other web sites - tacking on a picture, any picture, that has nothing to do with the subject at hand. See https://phys.org/...em.html. Same stupid picture having nothing to do with the article.
Turgent
1 / 5 (1) Mar 11, 2018
Increasing disturbing trend at phys.org and other web sites - tacking on a picture, any picture, that has nothing to do with the subject at hand.


Yes. Some are very misleading and detrimentally so.
Da Schneib
2.3 / 5 (3) Mar 12, 2018
One of the things not to lose sight of here is that this doesn't mean black holes are theoretically excluded. It just means that there are other things between BHs and neutron stars that we haven't found any demonstrable examples of; and we're not even sure they're stable solutions, so don't hold your breath until this math all gets worked out.

The paper is open access at arXiv: https://arxiv.org...06.05379
Anda
4 / 5 (4) Mar 12, 2018
Still there "aether guy"???
It's Mackita now... aren't you tired of writing the same nonsense over and over for years?
Spaced out Engineer
not rated yet Mar 12, 2018
Nevermind the fact that relativity and QM are incompatible.

Yes, relativity is wrong, but useful enough for all intensive purposes in some dimensialities, namely those of the 4th kind. A reduction whose illusion tells us there is more to time, whether we say by the collectively exhaustive or the maximally extended.

You bring the integer of dimension. I'll bring the mirroring of features. We will get by and by.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.