2MASS J0441+2301 is a young quadruple system hosting a

planetary-mass object A planetary-mass object (PMO), planemo, or planetary body is by geophysical definition of celestial objects any celestial object massive enough to achieve hydrostatic equilibrium (to be rounded under its own gravity), but not enough to sustain ...

, a

red dwarf ''Red Dwarf'' is a British science fiction comedy franchise created by Rob Grant and Doug Naylor, which primarily consists of a television sitcom that aired on BBC Two between 1988 and 1999, and on Dave since 2009, gaining a cult following. T ...

star and two

brown dwarf Brown dwarfs (also called failed stars) are substellar objects that are not massive enough to sustain nuclear fusion of ordinary hydrogen ( 1H) into helium in their cores, unlike a main-sequence star. Instead, they have a mass between the most ...

s, approximately 470

light years A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

(145

parsec The parsec (symbol: pc) is a unit of length used to measure the large distances to astronomical objects outside the Solar System, approximately equal to or (au), i.e. . The parsec unit is obtained by the use of parallax and trigonometry, and ...

s) away. The 2MASS J04414489+2301513 Bab primary (a brown dwarf) has a large separation (12.4 arcseconds) companion, 2MASS J04414565+2301580 Aa (abbreviated as 2M J044145), which in turn has a nearby small separation substellar companion (separation of 0.23

arcsecond A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc is of a turn. The na ...

s to the northeast). 2M J044145 has similar

proper motion Proper motion is the astrometric measure of the observed changes in the apparent places of stars or other celestial objects in the sky, as seen from the center of mass of the Solar System, compared to the abstract background of the more dista ...

to 2M J044144 and is likely physically associated with the system. The entire system of 4 objects is then a hierarchical quadruple of two binary objects orbiting each other. The primary component Aa has a spectral type of M4.5 and a red

apparent magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's li ...

of 14.2. Both components seem to be accreting mass from their stellar disks, as shown by their

emission line A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to iden ...

s. The four objects have a total mass of only 26% of the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

, making it the quadruple star system with the lowest mass known.

Planetary system

The primary is orbited by a companion about 5–10 times the mass of

Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but ...

. The mass of the primary brown dwarf is roughly 20 times the mass of Jupiter and its age is roughly one million years. It is not clear whether this companion object is a

sub-brown dwarf A sub-brown dwarf or planetary-mass brown dwarf is an astronomical object that formed in the same manner as stars and brown dwarfs (i.e. through the collapse of a gas cloud) but that has a planetary mass, therefore by definition below the limi ...

or a planet. The companion is very large with respect to its parent and must have formed within 1 million years or so. This seems to be too big and too fast to form like a regular

planet A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a you ...

from a disk around the central object.

References

* {{DEFAULTSORT:2MASS J04414489+2301513 4 Brown dwarfs Taurus (constellation) J04414489+2301513 M-type brown dwarfs Planetary systems with one confirmed planet TIC objects T Tauri stars

Planetary system

See also

References