Scholz's star

WISE J072003.20−084651.2

Observation data
Epoch J2000.0 [1]      Equinox J2000.0 [1]
Constellation Monoceros
Right ascension 07h 20m 03.254s [1]
Declination −08° 46′ 49.90″ [1]
Apparent magnitude (V) 18.3[2]
Characteristics
Spectral type M9 ± 1[2]
T5[2]
Astrometry
Radial velocity (Rv)83.1 [2] km/s
Proper motion (μ) RA: -40.3 ± 0.2[3][2] mas/yr
Dec.: -114.8 ± 0.4[3][2] mas/yr
Parallax (π)166 ± 28[3][2] mas
Distanceapprox. 20 ly
(approx. 6 pc)
Absolute magnitude (MV)19.4[4]
Details
Mass0.15[2] M☉
Age3–10 billion[2] years
Other designations
Scholz's Star,[5] Scholz's star,[2] WISE J072003.20−084651.2,[1] WISE 0720−0846, 2MASS J07200325−0846499,[1] 2MASS 0720−0846
Database references
SIMBADdata

Scholz's Star (WISE designation WISE 0720−0846 or fully WISE J072003.20−084651.2) is a dim binary stellar system about 17–23 light-years (5.1–7.2 parsecs) from the Sun in the southern constellation Monoceros near the galactic plane.[2] It was discovered in 2013 by astronomer Ralf-Dieter Scholz. It passed through the Solar System's Oort cloud roughly 70,000 years ago.

Characteristics

The primary is a red dwarf with a stellar classification of M9±1 and has 86±2 Jupiter masses.[2] The secondary is probably a T5 brown dwarf with 65±12 Jupiter masses.[2] The system has 0.15 solar masses.[2] The pair orbit at a distance of about 0.8 astronomical units (120,000,000 kilometers; 74,000,000 miles).[2] The system has an apparent magnitude of 18.3,[2] and is estimated to be between 3 and 10 billion years old.[2] With a parallax of 166 mas (0.166 arcseconds), there are about 80 known star systems closer to the Sun.[6] It is a late discovery, as far as nearby stars go, because past efforts concentrated on high-proper-motion objects.

Solar System flyby

Estimates indicate that the WISE 0720−0846 system passed about 52,000 astronomical units (0.25 parsecs; 0.82 light-years) from the Sun about 70,000 years ago.[2][5] 98% of mathematical simulations of the star system's trajectory indicated it passed through the Solar System's Oort cloud, or within 120,000 AU (0.58 pc; 1.9 ly) of the Sun.[2] Comets perturbed from the Oort cloud would require roughly 2 million years to get to the inner Solar System.[2] At closest approach the system would have had an apparent magnitude of about 11.4.[4] A star is expected to pass through the Oort Cloud every 100,000 years or so.[4] An approach as close or closer than 52,000 AU is expected to occur about every 9 million years.[2]

Naming

The star was first discovered to have been near the Solar System by astronomer Ralf-Dieter Scholz,[5] announced on arXiv in November 2013, and has been nicknamed Scholz's star.

See also

References

  1. 1 2 3 4 5 6 "2MASS J07200325-0846499 -- Brown Dwarf Candidate". SIMBAD. Retrieved 2015-02-18.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Mamajek, Eric E.; Barenfeld, Scott A.; Ivanov, Valentin D. (2015). "The Closest Known Flyby of a Star to the Solar System". The Astrophysical Journal 800 (1). arXiv:1502.04655. Bibcode:2015ApJ...800L..17M. doi:10.1088/2041-8205/800/1/L17.
  3. 1 2 3 Burgasser, Adam J.; Gillon, Michaël; Melis, Carl; Bowler, Brendan P.; Michelsen, Eric L.; Bardalez Gagliuffi, Daniella; Gelino, Christopher R.; Jehin, E.; Delrez, L.; Manfroid, J.; Blake, Cullen H. (2015). "WISE J072003.20-084651.2: an Old and Active M9.5 + T5 Spectral Binary 6 pc from the Sun". The Astronomical Journal 149 (3): 104. arXiv:1410.4288. Bibcode:2015AJ....149..104B. doi:10.1088/0004-6256/149/3/104.
  4. 1 2 3 Mamajek, Eric. "FAQ". Retrieved 2015-02-18.
  5. 1 2 3 "Featured Research: Closest known flyby of star to our solar system: Dim star passed through Oort Cloud 70,000 years ago". Science Daily. 17 February 2015. Retrieved 2015-02-21.
  6. ↑ "THE ONE HUNDRED NEAREST STAR SYSTEMS". RECONS (Research Consortium On Nearby Stars). Retrieved 2015-02-18.
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