List of least massive stars
Encyclopedia
This is a list of the least-massive star
s known. The list is ordered by solar mass
and Jovian mass
.
This list includes brown dwarf
s and red dwarf
s. The name of each brown dwarf
has background color brown, and the names of and red dwarf
s are against a background of red or orange, depending on whether they are cooler class M
or warmer class M
. (The objects are not actually these colors.)
Although brown dwarfs lack sufficient mass to ignite core hydrogen
fusion (75-87 Jupiters, depending on metallicity
), the smallest true stars (red dwarfs) can have such cool atmospheric temperatures (below 4,000 K), that it is difficult to distinguish them from brown dwarfs.
A star's mass cannot be lower than 13 Jupiter masses, because below this critical point the core does not get hot enough by gravitational pressure
to start the fusion of deuterium
. According to the brown dwarf interior models, typical conditions in the core for density, temperature, and pressure are expected to be the following:
A brown dwarf, therefore, is heavier than a gas-giant planet, but not quite massive enough to be a star.
The colour code for the table below is as follows: Brown = Brown Dwarf, Pink = Red Dwarf, Orange: Stars of stellar class "K"
.
is sometimes referred to as being the smallest brown dwarf
, but its mass is too light for this (8 times Jupiter's mass).
It is even smaller than some known exoplanets.
Therefore it can better be seen as a so-called sub-brown dwarf
or a planemo.
Some stars are listed as red dwarfs although they should be listed as brown dwarfs due to their mass, and vice versa.
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s known. The list is ordered by solar mass
Solar mass
The solar mass , , is a standard unit of mass in astronomy, used to indicate the masses of other stars and galaxies...
and Jovian mass
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
.
This list includes brown dwarf
Brown dwarf
Brown dwarfs are sub-stellar objects which are too low in mass to sustain hydrogen-1 fusion reactions in their cores, which is characteristic of stars on the main sequence. Brown dwarfs have fully convective surfaces and interiors, with no chemical differentiation by depth...
s and red dwarf
Red dwarf
According to the Hertzsprung-Russell diagram, a red dwarf star is a small and relatively cool star, of the main sequence, either late K or M spectral type....
s. The name of each brown dwarf
Brown dwarf
Brown dwarfs are sub-stellar objects which are too low in mass to sustain hydrogen-1 fusion reactions in their cores, which is characteristic of stars on the main sequence. Brown dwarfs have fully convective surfaces and interiors, with no chemical differentiation by depth...
has background color brown, and the names of and red dwarf
Red dwarf
According to the Hertzsprung-Russell diagram, a red dwarf star is a small and relatively cool star, of the main sequence, either late K or M spectral type....
s are against a background of red or orange, depending on whether they are cooler class M
Stellar classification
In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...
or warmer class M
Stellar classification
In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...
. (The objects are not actually these colors.)
Although brown dwarfs lack sufficient mass to ignite core hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
fusion (75-87 Jupiters, depending on metallicity
Metallicity
In astronomy and physical cosmology, the metallicity of an object is the proportion of its matter made up of chemical elements other than hydrogen and helium...
), the smallest true stars (red dwarfs) can have such cool atmospheric temperatures (below 4,000 K), that it is difficult to distinguish them from brown dwarfs.
A star's mass cannot be lower than 13 Jupiter masses, because below this critical point the core does not get hot enough by gravitational pressure
Gravitational binding energy
The gravitational binding energy of an object consisting of loose material, held together by gravity alone, is the amount of energy required to pull all of the material apart, to infinity...
to start the fusion of deuterium
Deuterium
Deuterium, also called heavy hydrogen, is one of two stable isotopes of hydrogen. It has a natural abundance in Earth's oceans of about one atom in of hydrogen . Deuterium accounts for approximately 0.0156% of all naturally occurring hydrogen in Earth's oceans, while the most common isotope ...
. According to the brown dwarf interior models, typical conditions in the core for density, temperature, and pressure are expected to be the following:
A brown dwarf, therefore, is heavier than a gas-giant planet, but not quite massive enough to be a star.
The colour code for the table below is as follows: Brown = Brown Dwarf, Pink = Red Dwarf, Orange: Stars of stellar class "K"
Stellar classification
In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...
.
| Star name | Solar Mass | Jupiter Mass |
|---|---|---|
| Jupiter Jupiter Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,... (as reference) |
0.00096 | 1 |
| ---------------- | ----- | -- |
| OTS 44 OTS 44 OTS 44 is a brown dwarf about 550 light-years away in the constellation Chamaeleon. It is among the smallest known brown dwarfs.OTS 44 has a mass of about 15 times that of Jupiter, or about 1.5 % that of the Sun... |
0.013 | 15 |
| Oph1622 A | 0.014 | 15.5 |
| Oph1622 B | 0.016 | 17.5 |
| Gliese 229B | 0.021 | 25 |
| 2M1207 2M1207 2M1207, 2M1207A or 2MASS J12073346-3932539 is a brown dwarf located in the constellation Centaurus; a companion object, 2M1207b, may be the first extrasolar planetary mass companion to be directly imaged, and is the first discovered orbiting a brown dwarf.2M1207 was discovered during the course of... |
0.021 | 25 |
| Epsilon Indi BB Epsilon Indi Epsilon Indi is a K-type main-sequence star approximately 12 light-years away in the constellation of Indus. Two brown dwarfs, found in 2003, orbit the star.- Observation :... |
0.024 | 28 |
| HD 98230B | 0.037 | 39 |
| Teide 1 Teide 1 Teide 1 was the first brown dwarf to be verified in 1995. This brown dwarf is located in the Pleiades open star cluster located approximately 400 light years from Earth.... |
0.041 | 43 |
| Epsilon Indi BA Epsilon Indi Epsilon Indi is a K-type main-sequence star approximately 12 light-years away in the constellation of Indus. Two brown dwarfs, found in 2003, orbit the star.- Observation :... |
0.045 | 47 |
| Wolf 424B | 0.050 | 52 |
| Gliese 570D | 0.050 | 52 |
| LP 944-020 | 0.056 | 58 |
| 2MASS 0415-0935 2MASS 0415-0935 2MASS J04151954-0935066 is a brown dwarf in the constellation Eridanus, located about 18.7 light-years from Earth. It was discovered in 2002 by Adam J. Burgasser et al. It belongs to the spectral class T8V; its surface temperature is 600-750 Kelvin. As with other brown dwarfs of spectral type T,... |
0.060 | 63 |
| Wolf 424A | 0.060 | 63 |
| DENIS 1048-0039 | 0.065 | 68 |
| 2MASS 1835+3259 2MASS 1835+3259 2MASS 1835+3259 is a nearby brown dwarf star of spectral class M8.5, located in constellation , the discovery of which was published in 2003, and it is the 3rd nearest M-type brown dwarf after DEN 1048-3956 and LP 944-020.Trigonometric parallax of this object, measured in 2001—2002 with the USNO... |
0.070 | 75 |
| DENIS 0255-4700 | 0.070 | 75 |
| V1581 Cygni C | 0.074 | 79 |
| 2MASS 0532+8246 2MASS 0532+8246 2MASS 0532+8246 is possibly the first halo brown dwarf and the first substellar subdwarf.* Mass: 0.077 – 0.085 MSun* Age: 10–15 Ga* Metallicity Z: 0.1 – 0.01 ZSun-References:... |
0.077 | 81 |
| LHS 3003 (GJ 3877) | 0.077 | 81 |
| Gliese 165B | 0.080 | 84 |
| Gliese 623B | 0.080 | 84 |
| LHS 1070B | 0.080 | 84 |
| LHS 1070C | 0.080 | 84 |
| Ross 614 Ross 614 Ross 614 or Gliese 234A is a red dwarf UV Cetiflare star and it is the primary member of a nearby binary star system in the constellation of Monoceros. This star has an magnitude of about 11, making it invisible to the unaided eye even though it is one of the stars nearest to the sun... B |
0.080 | 84 |
| Teegarden's Star Teegarden's star Teegarden's Star, also known as SO J025300.5+165258, is an M-type red dwarf star or brown dwarf in the constellation Aries, located about 12 light years from the Solar System. Despite its proximity to Earth it is a dim magnitude 15 and can only be seen through large telescopes. This star was found... |
0.080 | 84 |
| Van Biesbroeck's Star (VB 10) VB 10 VB 10, also referred to as Van Biesbroeck's star, is a very small and very dim M-type red dwarf star located in the constellation Aquila... |
0.080 | 84 |
| Gl 105C | 0.082 | 86 |
| LHS 292 | 0.083 | 87 |
| LP 731-058 | 0.083 | 87 |
| DX Cancri DX Cancri DX Cancri is a red dwarf star that is about 9% of the mass of our Sun. It is a flare star that has intermittent changes in brightness by up to a fivefold increase.... |
0.087 | 91 |
| Van Briesboeck 8 (VB 8) Van Biesbroeck's star catalog In 1961 the astronomer George Van Biesbroeck published a catalog of low luminosity stars discovered using the Otto Struve refractor telescope of the McDonald Observatory in Texas. This survey is similar to earlier dim star surveys that were done by Max Wolf and Frank Elmore Ross but using later... |
0.088 | 92 |
| AB Doradus C AB Doradus AB Doradus is a pre-main sequence trinary star system in the constellation Dorado. The primary is a flare star that shows periodic increases in activity.... |
0.089 | 93 |
| OGLE-TR-122b OGLE-TR-122b |-! style="background-color: #FFFFC0;" colspan="2" | Characteristics|-| Spectral type | ? /M |- style="vertical-align: top;"| Apparent magnitude '| 15.61 |- style="vertical-align: top;"... |
0.091 | 96 |
| Wolf 359 | 0.1 | 105 |
| ---------------- | ----- | -- |
| Sun Sun The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields... (as reference) |
1 | 1042 |
Cha 110913-773444
The object Cha 110913-773444Cha 110913-773444
Cha 110913-773444 is an astronomical object surrounded by what appears to be a protoplanetary disk...
is sometimes referred to as being the smallest brown dwarf
Brown dwarf
Brown dwarfs are sub-stellar objects which are too low in mass to sustain hydrogen-1 fusion reactions in their cores, which is characteristic of stars on the main sequence. Brown dwarfs have fully convective surfaces and interiors, with no chemical differentiation by depth...
, but its mass is too light for this (8 times Jupiter's mass).
It is even smaller than some known exoplanets.
Therefore it can better be seen as a so-called sub-brown dwarf
Sub-brown dwarf
A sub-brown dwarf is an astronomical object of planetary mass that is not orbiting a star and is not considered to be a brown dwarf because its mass is below the limiting mass for thermonuclear fusion of deuterium ....
or a planemo.
Some stars are listed as red dwarfs although they should be listed as brown dwarfs due to their mass, and vice versa.
See also
- List of most massive stars
- List of stars
- List of brown dwarfs