2MASS J0523-1403

from Wikipedia, the free encyclopedia
L-dwarf
2MASS J05233822−1403022
AladinLite
Observation
dates equinox :  J2000.0 , epoch : J2000.0
Constellation Hare
Right ascension 05 h 23 m 38.22 s
declination -14 ° 03 ′ 2 ″
Apparent brightness (21.05 ± 0.11) mag
Typing
rel. Brightness
(G-band) 		(18.06 ± 0.01) mag
rel. Brightness
(J-band) 		(13.08 ± 0.02) mag
Spectral class L2.5
Astrometry
Radial velocity (12.48 ± 0.41) km / s
parallax (78.36 ± 0.19)  mas
distance (41.60 ± 0.10)  ly
(12.76 ± 0.03)  pc
Proper movement 
Rec. Share: (107.25 ± 0.29)  mas / a
Dec. portion: (160.90 ± 0.34)  mas / a
Physical Properties
Dimensions (0.07)  M ☉
radius (0.10)  R ☉
Luminosity

(1.38 ± 0.07) × 10 −4  L ☉

Effective temperature (1939 ± 68)  K.
Other names
and catalog entries
2MASS catalog 2MASS J05233822−1403022 [1]
Other names 2MASSI J0523382-140302; 2MUCD 10390

Template: Infobox Star / Maintenance / MagGTemplate: Infobox Star / Maintenance / MagJ

2MASS J05233822−1403022 , or 2MASS J0523−1403 for short , is a red dwarf in the constellation Rabbit . It was published in 2003 by Kelle L. Cruz et al. discovered and belongs to the spectral class L2.5. In 2014 it was recognized that the object was a star. At that time it was the smallest, coolest and possibly also the lowest-mass known star with continuous hydrogen fusion . If the star had only slightly less mass, a brown dwarf would have formed instead . The star will linger on the main sequence for several billion years. Because unlike sun-like stars with 10 billion years on the main sequence , the hydrogen fusion in these extremely low-mass red dwarfs takes place much more slowly. In addition, these small stars are completely convective and can therefore effectively fuse a significantly higher proportion of the hydrogen available in the star during their lifetime.

Discovery of nature as a star

In their search for the lightest star, the astronomers selected 63 objects in the immediate vicinity and examined their size and effective temperature . Interestingly, the gravitational pressure in brown dwarfs has the effect that they become smaller (and therefore denser) the more mass they have. Only the energy of the hydrogen burning creates a counter pressure, which with more mass leads to a larger radius again. So the smallest object with a higher effective temperature had to be a star, and this was 2MASS J0523-1403.

Web links

Individual evidence

  1. ↑ a b c d e f g 2MASS J05233822-1403022. In: SIMBAD . Center de Données astronomiques de Strasbourg , accessed on October 11, 2019 .
  2. ^ A b Sergio B. Dieterich, Todd J. Henry, Wei-Chun Jao, Jennifer G. Winters, Altonio D. Hosey, Adric R. Riedel, John P. Subasavage: The Solar Neighborhood XXXII. The Hydrogen Burning Limit . In: The Astronomical Journal . 147, No. 5, May 2014. arxiv : 1312.1736 . bibcode : 2014AJ .... 147 ... 94D . doi : 10.1088 / 0004-6256 / 147/5/94 .
  3. ↑ a b c d Joseph C. Filippazzo, Emily L. Rice, Jacqueline Faherty, Kelle L. Cruz, Mollie M. Van Gordon, Dagny L. Looper: Fundamental Parameters and Spectral Energy Distributions of Young and Field Age Objects with Masses Spanning the Stellar to Planetary Regime . In: The Astrophysical Journal . 810, No. 2, 2015, p. 158. arxiv : 1508.01767 . doi : 10.1088 / 0004-637X / 810/2/158 .
  4. ^ Kelle L. Cruz, I. Neill Reid, James Liebert, J. Davy Kirkpatrick, Patrick J. Lowrance: Meeting the Cool Neighbors. V. A 2MASS-Selected Sample of Ultracool Dwarfs . In: The Astronomical Journal . 126, No. 5, 2003, pp. 2421-2448. arxiv : astro-ph / 0307429 . bibcode : 2003AJ .... 126.2421C . doi : 10.1086 / 378607 .
  5. ↑ a b Phil Plait: The Smallest Star. June 11, 2014, accessed October 11, 2019 .