Nebula | |
---|---|
Observation data: J2000.0 [1] epoch | |
Right ascension | 04h 41.0m [1] |
Declination | +25° 52′ [1] |
Constellation | Taurus |
Designations | HCL 2, Heiles's cloud 2, TMC-1, Taurus molecular cloud 1 [1] |
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. [2] The Taurus molecular cloud is only 140 pc (430 ly) away from Earth, making it possibly the nearest large star formation region. It has been important in star formation studies at all wavelengths. [3]
It is notable for containing many complex molecules, such as cyanopolyynes HCnN for n = 3,5,7,9, [4] and cumulene carbenes H2Cn for n = 3–6. [5]
The Taurus molecular cloud was identified in the past as a part of the Gould Belt, a large structure surrounding the solar system. More recently (January 2020) the Taurus molecular cloud was identified as being part of the much larger Radcliffe wave, a wave-shaped structure in the local arm of the Milky Way.
The newly formed stars in this cloud have an age of 1–2 million years. [6] The Taurus–Auriga association, which is the stellar association of the cloud, contains the variable star T Tauri, which is the prototype of T Tauri stars. [7] The many young stars and the close proximity to earth make it uniquely well-suited to search for protoplanetary disks and exoplanets around stars, and to identify brown dwarfs in the association. Members of this region are suited for direct imaging of young exoplanets, which glow brightly in infrared wavelengths.
Members [7] [8] of the Taurus–Auriga association with a circumstellar disk or exoplanet:
Telescopium Herschelii, also formerly known as Tubus Hershelli Major, is a former constellation in the northern celestial hemisphere. Maximilian Hell established it in 1789 to honour Sir William Herschel's discovery of the planet Uranus. It fell out of use by the end of the 19th century. Psi2 Aurigae at apparent magnitude 4.8 was the constellation's brightest star.
45 Aurigae or PLX 1468.2 is a binary star system in the northern constellation of Auriga. It has an apparent visual magnitude of 5.34, making it visible to the naked eye under suitable viewing conditions. An annual parallax shift of 16.89 mas as seen from Earth's orbit indicates the system is located about 193 light years from the Sun.
SU Aurigae is a T Tauri-type variable star in the constellation Auriga. It is located about 500 light-years away in the Taurus-Auriga Star Forming Region. Its apparent magnitude is 9.30, which is dim enough that it cannot be seen with the unaided eye.
XZ Tauri is a binary system approximately 460 light-years away in the constellation Taurus. The system consists of two T Tauri stars orbiting each other about 6 billion kilometers apart. The system made news in 2000 when a superflare was observed in the system.
AA Tauri is a young variable star in the equatorial constellation of Taurus, located in the Taurus-Auriga star-forming region. It is too faint to view with the naked eye, having an apparent visual magnitude that varies from 12.2 down to 16.1. The star is located approximately 439 light-years away from the Sun based on parallax, and is drifting further away with a radial velocity of +17 km/s.
AB Aurigae is a young Herbig Ae star in the Auriga constellation. It is located at a distance of approximately 531 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.
Sigma Herculis, Latinized from σ Her, is a binary star system in the northern constellation of Hercules. It has a combined apparent visual magnitude of 4.18, making it bright enough to be visible to the naked eye. Based upon an annual parallax shift of 10.36 mas as seen from Earth, Sigma Herculis is located about 310 light years away from the Sun.
HL Tauri is a young T Tauri star in the constellation Taurus, approximately 450 light-years (140 pc) from Earth in the Taurus Molecular Cloud. The luminosity and effective temperature of HL Tauri imply that its age is less than 100,000 years. At apparent magnitude 15.1, it is too faint to be seen with the unaided eye. It is surrounded by a protoplanetary disk marked by dark bands visible in submillimeter radiation that may indicate a number of planets in the process of formation. It is accompanied by the Herbig–Haro object HH 150, a jet of gas emitted along the rotational axis of the disk that is colliding with nearby interstellar dust and gas.
RCW 36 is an emission nebula containing an open cluster in the constellation Vela. This H II region is part of a larger-scale star-forming complex known as the Vela Molecular Ridge (VMR), a collection of molecular clouds in the Milky Way that contain multiple sites of ongoing star-formation activity. The VMR is made up of several distinct clouds, and RCW 36 is embedded in the VMR Cloud C.
MWC 480 is a single star, about 500 light-years away in the constellation of Auriga. It is located in the Taurus-Auriga Star-Forming Region. The name refers to the Mount Wilson Catalog of B and A stars with bright hydrogen lines in their spectra. With an apparent magnitude of 7.62, it is too faint to be seen with the naked eye.
Phi Fornacis is a single star in the southern constellation of Fornax. It has a white hue and is faintly visible to the naked eye with an apparent visual magnitude of 5.13. The distance to this object is approximately 154 light-years based on parallax, and it is drifting further away with a radial velocity of +19 km/s.
LkCa 15 is a T Tauri star in the Taurus Molecular Cloud. These types of stars are relatively young pre-main-sequence stars that show irregular variations in brightness. It has a mass that is about 97% of the Sun, an effective temperature of 4370 K, and is slightly cooler than the Sun. Its apparent magnitude is 11.91, meaning it is not visible to the naked eye.
GG Tauri, often abbreviated as GG Tau, is a quintuple star system in the constellation Taurus. At a distance of about 450 light years away, it is located within the Taurus-Auriga Star Forming Region. The system comprises three stars orbiting each other in a hierarchical triple system, known as GG Tauri A, and another binary star system more distant from the central system, known as GG Tauri B.
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. Around the planets, they are the reservoirs of material out of which moons may form. Such a disk can manifest itself in various ways.
V1298 Tauri is a young weakly-lined T Tauri star that is part of the Taurus-Auriga association in the Taurus Molecular Cloud. Alternatively it is part of a proposed moving group, called Group 29 that is slightly older. The system has four transiting exoplanets, discovered with the Kepler space telescope in the K2 mission. One of the planets was discovered in August 2019 and the other three were discovered in November 2019 by the same team.
FU Tauri is a brown dwarf binary system in the constellation of Taurus about 429 light years away. The secondary is very close to the lower limit for brown dwarfs and several databases list it as a distant massive exoplanet.
RY Tauri is a young T Tauri star in the constellation of Taurus about 450 light years away, belonging to the Taurus Molecular Cloud. It is more massive than typical T Tauri stars, and may be an intermediate between this class and the Herbig Ae/Be star type.
GK Tauri is a young binary system composed of T Tauri-type pre-main sequence stars in the constellation of Taurus about 466 light years away, belonging to the Taurus Molecular Cloud.
DL Tauri is a young T Tauri-type pre-main sequence stars in the constellation of Taurus about 522 light years away, belonging to the Taurus Molecular Cloud. It is partially obscured by the foreground gas cloud rich in carbon monoxide, and is still accreting mass, producing 0.14 L☉ due to release of accretion energy. The stellar spectrum shows the lines of ionized oxygen, nitrogen, sulfur and iron.
LDN 1641 or Lynds 1641 is a dark cloud in the constellation Orion. It encompasses a large part of the Orion A molecular cloud in the Orion Molecular Cloud Complex, which is the closest giant molecular cloud to earth. At its northern end it is connected to the Orion Nebula and at its southern end it is connected to the dark cloud LDN 1647. LDN 1641 contains more than a thousand Young Stellar Objects (YSOs). It is a relative low density star-forming region without any massive O- or B-type stars that could disturb the formation of young stars with their ultraviolet radiation. This means that researchers can study star formation that is happening in a very different environment when compared to the Orion Nebula.