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2MASS J04070752+1546457

2MASS J04070752+1546457 (abbreviated to 2MASS J0407+1546) is a rapidly-rotating brown dwarfofspectral class L3.5, located in the constellation Taurus about 119 light-years from Earth. With a photometrically measured rotation period of 1.23 hours, it is one of the fastest-rotating known brown dwarfs announced by a team of astronomers led by Megan E. Tannock in March 2021. With a rotational velocity of over 80 km/s (50 mi/s), it is approaching the predicted rotational speed limit beyond which it would break apart due to centripetal forces. As a consequence of its rapid rotation, the brown dwarf is slightly flattened at its poles to a similar degree as Saturn, the most oblate planet in the Solar System.^[3] Its rapid rotation may enable strong auroral radio emissions via particle interactions in its magnetic field, as observed in other known rapidly-rotating brown dwarfs.^[2]

Discovery[edit]

2MASS J0407+1546 was first catalogued as a point source in June 2003 by the Two Micron All-Sky Survey (2MASS) organized by the University of Massachusetts Amherst and the Infrared Processing and Analysis Center under the California Institute of Technology.^[4] It was discovered to be a brown dwarf of the spectral class L3.5 by I. Neill Reid and collaborators, based on near-infrared spectra obtained in October 2005 with the Gemini North at the Mauna Kea Observatory, Hawaii. Their discovery and spectroscopic characterization of 430 ultracool dwarfs including 2MASS J0407+1546 was published in The Astronomical Journal in September 2008.^[5]

Distance[edit]

The trigonometric parallax of 2MASS 1114−2618 was measured to be 27.4408±1.7735 milliarcseconds by the Gaia spacecraft in 2018, corresponding to a distance of 36.4 ± 2.4 parsecs (118.7 ± 7.8 ly).^[1] This is in close agreement with Reid et al.'s spectrophotometric estimate of 33.1 ± 3.3 parsecs (108 ± 11 ly) in 2008, calculated from the object's spectral type and near-infrared absolute magnitude.^[5]

Proper motion[edit]

From Gaia DR2, 2MASS J0407+1546 has a measured net proper motion of 81.0 mas/yr with position angle 139.06 degrees,^[a][b] indicating motion in south-east direction on the sky.^[1]

See also[edit]

• 2MASS J12195156+3128497 – L8 spectral class brown dwarf with a period of 1.14+0.03
  −0.01 h
• 2MASS J03480772−6022270 – T7 spectral class brown dwarf with a period of 1.080+0.004
  −0.005 h

Notes[edit]

1. ^ The net proper motion is given by: ${\displaystyle \mu ={\sqrt {{\mu _{\delta }}^{2}+{\mu _{\alpha }}^{2}\cdot \cos ^{2}\delta }}\approx 81.0}$ mas/yr, where ${\displaystyle \mu _{\alpha }}$ and ${\displaystyle \mu _{\delta }}$ are the components of proper motion in the RA and Dec, respectively.

^ The position angle of proper motion is given by ${\displaystyle \tan ^{-1}\left({\frac {\mu _{\delta }}{\mu _{\alpha }}}\right)}$

References[edit]

External links[edit]

• Trio of Fast-Spinning Brown Dwarfs May Reveal a Rotational Speed Limit, Calla Cofield, Jet Propulsion Laboratory, 7 April 2021
• Western space scientists identify fastest-spinning "failed stars" ever found, Jeff Renaud, University of Western Ontario, 7 April 2021
• Caught Speeding: Clocking the Fastest-Spinning Brown Dwarfs, NOIRLab, 7 April 2021