Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Taurus |
Right ascension | 04h 19m 01.28s |
Declination | +28° 02′ 48.14″ |
Apparent magnitude (V) | 23.228±0.023 [1] |
Characteristics | |
Evolutionary stage | low-mass brown dwarf or planetary-mass object |
Spectral type | M9.25±0.5 [2] |
Astrometry | |
Proper motion (μ) | RA: 7.09±5.60 mas/yr [3] Dec.: −28.41±5.27 mas/yr [3] |
Distance | 473 ± 49 ly (145±15 pc) [3] |
Details | |
Mass | 12.7+1.6 −1.8 [4] MJup |
Radius | 2.22+0.11 −0.17 [4] RJup |
Luminosity (bolometric) | 10−2.99±0.16 [3] L☉ |
Temperature | 2170±200 [3] K |
Rotational velocity (v sin i) | 5.0 [5] km/s |
Age | 1-10 [3] Myr |
Other designations | |
Database references | |
SIMBAD | data |
KPNO-Tau 12 (also called 2MASS J0419012+280248) is a low-mass brown dwarf or free-floating planetary-mass object that is surrounded by a protoplanetary disk, actively accreting material from it. [6]
KPNO-Tau 12 was identified in 2003 in data from a survey of the Taurus Molecular Clouds taken with a telescope at the Kitt Peak National Observatory (KPNO) and 2MASS. The object was observed with the MMT Observatory/Blue Channel spectrometer and with Keck/LRIS. KPNO-Tau 12 showed a spectral type of M9 and also showed strong Hydrogen-alpha emission. At the time its mass was estimated to be around 0.02 M☉ (or 21 MJ), which would make it a brown dwarf. [6] Since then several works found that it likely has a mass near or below the deuterium-burning limit, which makes this object a low-mass brown dwarf or planetary-mass object (e.g. 14.6 MJ, [1] 13.6 MJ, [7] 6-7 MJ, [2] 16.5 MJ, [8] 17.8+6.7
−4.6MJ, [9] 12.7+1.6
−1.8MJ [4] ).
A few other free-floating planetary-mass objects are known in the Taurus Clouds. [10] [11] These include three other objects with possible disks around them. [11]
Observations with Keck/LRIS showed several absorption features. These are titanium oxide, calcium hydride, vanadium oxide, sodium and potassium. [6] A spectrum with Keck/NIRSPEC was interpreted to be consistent with very low gravity. This is typical for young sources. [12] Several re-classifications of the spectral type were made over the years. In 2013 it was re-classified as a M9.25±0.5. [2] In 2018 it was re-classified as a L0.7±1.1, which could make this object an early L-dwarf. [3] A spectrum observed with VLT/SINFONI was published in 2022, estimating a spectral type of M9.8. [13]
KPNO-Tau 12 showed strongest H-alpha emission in both the MMT and Keck optical spectra. It also showed helium (He I) and calcium (Ca II IR triplet) emission in the Keck spectrum, which are usually seen in stars that undergo intense accretion of material from a surrounding protoplanetary disk. [6] Additionally a Keck infrared spectrum shows a prominent emission line (see figure 10 of their work), which is described as Paschen β at 1.28 μm in the appendix of the paper. [12] Paschen lines can be used as additional accretion indicators. [14] In 2010 two works used observations with the Spitzer Space Telescope. These two works first identified infrared excess around KPNO-Tau 12 and classified it as a class II disk. A class II disk is composed of both a gaseous and a dusty part and belongs to the protoplanetary disks. [15] [16] Observation with the Spitzer Infrared Spectrograph showed that the silicate emission feature is likely missing. [17] The dust mass of the disk was estimated to be 1.223 ME [8] or 0.6–1.1 ME, [18] depending on the work. The total (gas+dust) mass was estimated to be 0.66 MJ [9] or 0.095 MJ, [19] depending on the work. The dust temperature was estimated to be 7.0±13.8 Kelvin and the dust grains are smaller than 27.5 millimeters. [18]
Disks (in order from star) | Periapsis (AU) | Apoapsis (AU) | Inclination | Mass |
---|---|---|---|---|
protoplanetary disk | 0.003 | 6.4–95.5 | 25.50°–26.30° | 30 [19] –210 [9] ME |
Other free-floating planetary-mass objects with disks:
Other planetary-mass objects with disks that bound to a star:
Brown dwarfs are substellar objects that have more mass than the biggest gas giant planets, but less than the least massive main-sequence stars. Their mass is approximately 13 to 80 times that of Jupiter (MJ)—not big enough to sustain nuclear fusion of ordinary hydrogen (1H) into helium in their cores, but massive enough to emit some light and heat from the fusion of deuterium (2H). The most massive ones can fuse lithium (7Li).
A proplyd, short for ionized protoplanetary disk, is an externally illuminated photoevaporating protoplanetary disk around a young star. Nearly 180 proplyds have been discovered in the Orion Nebula. Images of proplyds in other star-forming regions are rare, while Orion is the only region with a large known sample due to its relative proximity to Earth.
A rogue planet, also termed a free-floating planet (FFP) or an isolated planetary-mass object (iPMO), is an interstellar object of planetary mass which is not gravitationally bound to any star or brown dwarf.
OTS 44 is a free-floating planetary-mass object or brown dwarf located at 530 light-years (160 pc) in the constellation Chamaeleon near the reflection nebula IC 2631. It is among the lowest-mass free-floating substellar objects, with approximately 11.5 times the mass of Jupiter, or approximately 1.1% that of the Sun. Its radius is estimated to be 3.2 or 3.6 times that of Jupiter.
An object with the spectral type L can be either a low-mass star, a brown dwarf or a young free-floating planetary-mass object. If a young exoplanet or planetary-mass companion is detected via direct imaging, it can also have an L spectral type, such as Kappa Andromedae b.
The Taurus molecular cloud (TMC-1) is an interstellar molecular cloud in the constellations Taurus and Auriga. This cloud hosts a stellar nursery containing hundreds of newly formed stars. The Taurus molecular cloud is only 140 pc away from Earth, making it possibly the nearest large star formation region. It has been important in star formation studies at all wavelengths.
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, but not enough to sustain core fusion like a star.
AB Aurigae is a young Herbig Ae star in the Auriga constellation. It is located at a distance of approximately 509 light years from the Sun based on stellar parallax. This pre-main-sequence star has a stellar classification of A0Ve, matching an A-type main-sequence star with emission lines in the spectrum. It has 2.4 times the mass of the Sun and is radiating 38 times the Sun's luminosity from its photosphere at an effective temperature of 9,772 K. The radio emission from the system suggests the presence of a thermal jet originating from the star with a velocity of 300 km s−1. This is causing an estimated mass loss of 1.7×10−8 M☉ yr−1.
WISE J014656.66+423410.0 is a binary brown dwarf of spectral classes T9 and Y0 located in the constellation Andromeda. It is approximately 60 light-years from Earth.
PSO J318.5−22 is an extrasolar object of planetary mass that does not orbit a parent star, it is an analog to directly imaged young gas giants. There is no consensus yet among astronomers whether the object should be referred to as a sub-brown dwarf, as a rogue planet or as a young brown dwarf. It is approximately 80 light-years away and belongs to the Beta Pictoris moving group. The object was discovered in 2013 in images taken by the Pan-STARRS PS1 wide-field telescope. PSO J318.5-22's age is inferred to be 23 million years, the same age as the Beta Pictoris moving group. Based on its calculated temperature and age, it is classified under the brown dwarf spectral type L7.
A circumplanetary disk is a torus, pancake or ring-shaped accumulation of matter composed of gas, dust, planetesimals, asteroids or collision fragments in orbit around a planet. They are reservoirs of material out of which moons may form. Such a disk can manifest itself in various ways.
A Peter Pan disk is a circumstellar disk around a star or brown dwarf that appears to have retained enough gas to form a gas giant planet for much longer than the typically assumed gas dispersal timescale of approximately 5 million years. Several examples of such disks have been observed to orbit stars with spectral types of M or later. The presence of gas around these disks has generally been inferred from the total amount of radiation emitted from the disk at infrared wavelengths, and/or spectroscopic signatures of hydrogen accreting onto the star. To fit one specific definition of a Peter Pan disk, the source needs to have an infrared "color" of , an age of >20 Myr and spectroscopic evidence of accretion.
ROXs 12 is a binary system of pre-main-sequence stars. It belongs to the Rho Ophiuchi cloud complex. The surface temperature of the primary star is 3900±100 K. ROXs 12 is much younger than the Sun with an age of 7.6+4.1
−2.5 million years.
HK Tauri is a young binary star system in the constellation of Taurus about 434 light-years away, belonging to the Taurus Molecular Cloud.
CFHTWIR-Oph 98 B is a substellar object, either an exoplanet or a sub-brown dwarf that orbits CFHTWIR-Oph 98 A, a M-type brown dwarf. The pair form a binary system. The primary is a M9–L1 dwarf and the secondary is an L dwarf with a spectral type of L2–L6. Both spectral types are estimated from photometry. The pair is separated by 200 astronomical units and has a low gravitational binding energy. The primary Oph 98A has a spectrum taken in 2012 with VLT/ISAAC, matching a spectral type of M9.75 and from Spitzer photometry and near-infrared photometry it is surrounded by a class II disk. This disk has a mass of 0.135 MJ according to a study using SED-modelling.
HD 163296 is a young Herbig Ae star that is surrounded by a protoplanetary disk. The disk is a popular target to study disk composition and several works suggested the presence of protoplanets inside the gaps of the disk.
BD+29 5007 is a K-type star, located 77 light-years in the constellation Pegasus. It has a large-separation companion that was identified in 2016. The pair was identified to be a possible member of the 45+15
−5 million years old Argus association, though this is disputed.