Scholz's Star

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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]
Spectral type M9 ± 1[2]
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
Distance approx. 20 ly
(approx. 6 pc)
Absolute magnitude (MV) 19.4[4]
Mass 0.15[2] M
Temperature 3325.75+97.5
Age 3–10[2] Gyr
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

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. In 2015, Eric Mamajek and collaborators reported the system passed through the solar system's Oort cloud roughly 70,000 years ago,[2] and dubbed it Scholz's Star.


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] with a period of roughly 4 years.[6] 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), about 80 star systems are known to be closer to the Sun.[7] It is a late discovery, as far as nearby stars go, because past efforts concentrated on high-proper-motion objects.[citation needed]

In 2018, further research was published indicating that disturbance of the Oort Cloud had a greater effect than initial research indicated.[8][9][10]

Solar System flyby[edit]

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, and would have been best viewed from high latitudes in the northern hemisphere, in the autumn mostly.[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] In about 1.4 million years, Gliese 710 will pass somewhere between 8,800 and 13,700 AU from the Sun.


The star was first discovered to be a nearby one by astronomer Ralf-Dieter Scholz,[5] announced on arXiv in November 2013. Given the importance of the system having passed so close to the solar system in prehistorical times, Eric Mamajek and collaborators dubbed the system Scholz's star in their paper discussing the star's velocity and past trajectory.[2]

See also[edit]


  1. ^ a b c d e f "2MASS J07200325-0846499". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2015-02-18. 
  2. ^ a b c d e f g h i j k l m n o p q r s t u v w 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:1502.04655Freely accessible. Bibcode:2015ApJ...800L..17M. doi:10.1088/2041-8205/800/1/L17. 
  3. ^ a b c Burgasser, Adam J.; et al. (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:1410.4288Freely accessible. Bibcode:2015AJ....149..104B. doi:10.1088/0004-6256/149/3/104. 
  4. ^ a b c Mamajek, Eric. "FAQ". Retrieved 2015-02-18. 
  5. ^ a b c "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. ^ Burgasser, Adam J.; et al. (2015). "Radio Emission and Orbital Motion from the Close-encounter Star–Brown Dwarf Binary WISE J072003.20–084651.2". The Astronomical Journal. 150 (6). 180. arXiv:1508.06332Freely accessible. Bibcode:2015AJ....150..180B. doi:10.1088/0004-6256/150/6/180. 
  7. ^ "THE ONE HUNDRED NEAREST STAR SYSTEMS". RECONS (Research Consortium On Nearby Stars). Retrieved 2015-02-18. 
  8. ^ de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl; Aarseth, Sverre J.; (2018-05-01). Where the Solar system meets the solar neighbourhood: patterns in the distribution of radiants of observed hyperbolic minor bodies, Monthly Notices of the Royal Astronomical Society: Letters, Volume 476, Issue 1, 1 May 2018, Pages L1–L5, published on 6 February 2018. Retrieved from
  9. ^ Warren, Matt (2018-03-22). Prehistoric visit from nearby star disturbed comets in our solar system, Science, 22 March 2018. Retrieved from
  10. ^ Dvorsky, George (2018-03-21). A Visiting Star Jostled Our Solar System 70,000 Years Ago, Gizmodo, 21 March 2018. Retrieved from