Ahypothetical star is a star, or type of star, that is speculated to exist but has yet to be definitively observed. Hypothetical types ofstars have been conjectured to exist, have existed or will exist in the futureuniverse.
Scientifically speculated hypothetical types include:
| Type | Description | Candidates | Notes | Citations |
|---|---|---|---|---|
| Blitzar | Pulsar with enough mass to suddenly collapse into ablack hole when the rotation speed slows. | |||
| Blue dwarf | Conjectured to develop after ared dwarf has exhausted most of its hydrogen. | — | The universe isn't old enough for this form to come into existence. | |
| Black dwarf | The final state for a star, like theSun, that is too small to become either a black hole or aneutron star. It would take a star like the Sun roughly a quadrillion (1015) years to reach this state, so none are believed to exist today. | — | The universe isn't old enough for this form to come into existence. | |
| Black star | A star predicted insemiclassical gravity which collapses into a black hole state but has neither agravitational singularity nor anevent horizon. | none | ||
| Boson star | A star orastronomical object made ofbosons, such asphotons orgluons, rather than conventional matter. | none | ||
| Dark energy star | A conjectured alternative to a black hole. | none | ||
| Dark matter star | Conjectured to have existedearly in the universe. | JADES-GS-z13-0,JADES-GS-z12-0, andJADES-GS-z11-0 | ||
| Dark star | A theoretical construct based onNewtonian gravitation, of a star with gravity so strong that even light cannot escape. | — | This form cannot exist, as Newtonian gravitation breaks down under these conditions. It is a disproved hypothesis | |
| Electroweak star | A star where gravitational collapse is prevented byradiation pressure resulting fromelectroweak burning. In this type of star,quarks are converted toleptons via theelectroweak interaction. The core of the star would be hand-sized, containing perhaps two earth masses, and might follow from the collapse of aquark star. | none | ||
| Frozen star | A very low-mass star with a surface temperature of only around 300kelvins that could form in the far future, when themetallicity of theinterstellar medium is higher than the current value. | — | The universe isn't old enough for this form to come into existence. | [1] |
| Fuzzball | A formulation of black holes instring theory. | none | ||
| Gravastar | An alternative to a black hole that denies the possibility of asingularity. | none | ||
| Hyperon star | A massive neutron star containinghyperons. | PSR J0348+0432 | [2][3] | |
| Iron star | A final state for a star in the far future (101500 years) of the universe, when all matter is transmuted to iron viaquantum tunneling. | — | The universe isn't old enough for this form to come into existence. | |
| MECO | A hypothetical alternative to black holes. | Q0957+561 | ||
| Planck star | A star where the energy density is around thePlanck density. The star will start to expand as soon as its density reaches thePlanck constant. To the black hole, it expands instantly, but to the outside world, it takes eons to expand even the slightest. | none | ||
| Population III star | The very earliest stars, virtually free ofmetals, believed to have existed in the early universe when the only common elements were primordial hydrogen and helium. | none | ||
| Preon star | A star with a core composed ofpreons. | none | ||
| Q star (grey hole) | A compact, heavy neutron star with an exoticstate of matter where most light does not escape the star. | V404 Cygni | [4] | |
| Quark star | Star composed ofquark matter orstrange matter. | 3C 58,PSR B0943+10,XTE J1739-285 | ||
| Quasi-star | A conjectured star from the early universe with a black hole at its center. | The Cliff | ||
| Strange star | A form ofquark star, aneutron star withstrange matter at its core, or star which is a ball of strange matter. | none | ||
| Thorne–Żytkow object | Ared giant,red supergiant, orWolf–Rayet star whosecore is aneutron star. | HV 11417 | ||
| White hole | The polar opposite of ablack hole, it ejects matter from its core into space. It is hypothetically formed when a region around a black hole experiences a loss in entropy, and will immediately collapse when the entropy is restored. The loss of entropy allows the black hole to travel back in time, so it will continue to suck matter up into its event horizon, but once something goes into the event horizon of a white hole, space-time is so distorted that it will always lead you to outside the event horizon, even if you try to go to the singularity. | GRB 060614 |
Specific hypothetical stars include:
| Star | Description | Notes | Citations |
|---|---|---|---|
| Nemesis | a star proposed as a companion to the Sun byRichard A. Muller in 1984 | This star was disproved in 2011. | |
| Coatlicue | a star thought to be the reason for how the Sun (and many other stars) came to be, proposed byMatthieu Gounelle andGeorges Meynet in 2012 | ||
| 3 Cassiopeiae | a star recorded by astronomerJohn Flamsteed, but never seen again | ||
| 34 Tauri | a star recorded byJohn Flamsteed later revealed to have been the planetUranus |
| Formation | |||||||
|---|---|---|---|---|---|---|---|
| Evolution | |||||||
| Classification |
| ||||||
| Nucleosynthesis | |||||||
| Structure | |||||||
| Properties | |||||||
| Star systems | |||||||
| Earth-centric observations | |||||||
| Lists | |||||||
| Related | |||||||
