Scholz's Star

Coordinates: Sky map 07h 20m 03.254s, −08° 46′ 49.90″
From Wikipedia, the free encyclopedia
WISE J072003.20−084651.2
Scholz's Star is located in the constellation Monoceros
Scholz's Star is located in the constellation Monoceros
Scholz's Star
Location of Scholz's Star in the constellation Monoceros

Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Monoceros
Right ascension 07h 20m 03.254s[1]
Declination −08° 46′ 49.90″[1]
Apparent magnitude (V) 18.3[2]
Red dwarf
Spectral type M9.5±0.5[3]
Brown dwarf
Spectral type T5.5±0.5[3]
Radial velocity (Rv)82.4±0.3[3] km/s
Proper motion (μ) RA: −40.3±0.2[2][4] mas/yr
Dec.: −114.8±0.4[2][4] mas/yr
Parallax (π)147.1 ± 1.2 mas
Distance22.2 ± 0.2 ly
(6.80 ± 0.06 pc)
Absolute magnitude (MV)19.4[5]
PrimaryScholz's Star A
CompanionScholz's Star B
Period (P)8.06+0.24
Semi-major axis (a)0.320±0.003"
Eccentricity (e)0.240+0.009
Inclination (i)106.9±0.4°
Longitude of the node (Ω)240.21±0.28°
Periastron epoch (T)2015/09/16+23−28
Argument of periastron (ω)
Red dwarf
Mass0.095±0.006[3] M
Age3–10[2] Gyr
Brown dwarf
Mass0.063±0.004[3] M
Other designations
Scholz's Star,[6] Scholz's star, WISE J072003.20−084651.2, WISE 0720−0846, 2MASS J07200325−0846499, 2MASS 0720−0846[7]
Database references

Scholz's Star /ˈʃlz(əz)/ (WISE designation WISE 0720−0846 or fully WISE J072003.20−084651.2) is a dim binary stellar system 22 light-years (6.8 parsecs) from the Sun in the 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.


Scholz's Star with ESO's VPHAS+

The primary is a red dwarf with a stellar classification of M9±1 and 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 million kilometres; 74 million miles)[2] with a period of roughly 4 years.[8] 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.[9] It is a late discovery, as far as nearby stars go, because past efforts concentrated on high-proper-motion objects.[citation needed]

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][6][10] Ninety-eight percent of mathematical simulations of the star system's trajectory indicated that 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 two 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.[5]

In 2018, research was published indicating that disturbance of the Oort cloud will have a greater effect than initial research had indicated.[11] [12][13]

In a recent estimate, WISE J0720−0846AB passed within 68.7 ± 2.0 kAU of the Sun 80.5 ± 0.7 kyr ago.[3] A later recalculation of the impact parameters using updated Solar System data showed that the perihelion distance during the encounter had a median value of 0.330 pc with a 90% probability of having come within 0.317–0.345 pc of the Sun; the associated time of perihelion passage was determined to be between 78.6–81.1 kyr ago with 90% confidence, with a most likely value of 79.9 kyr.[14]

A star is expected to pass through the Oort cloud every 100,000 years or so.[5] 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 come to a perihelion of between 8,800 and 13,700 AU.[10]


The star was first discovered to be a nearby one by astronomer Ralf-Dieter Scholz,[6] 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 Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
  2. ^ a b c d e f g h i j k l m n o p q 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): L17. arXiv:1502.04655. Bibcode:2015ApJ...800L..17M. doi:10.1088/2041-8205/800/1/L17. S2CID 40618530.
  3. ^ a b c d e f g Dupuy, Trent J.; Liu, Michael C.; Best, William M. J.; Mann, Andrew W.; Tucker, Michael A.; Zhang, Zhoujian; Baraffe, Isabelle; Chabrier, Gilles; Forveille, Thierry; Metchev, Stanimir A.; Tremblin, Pascal; Do, Aaron; Payne, Anna V.; Shappee, B. J.; Bond, Charlotte Z.; Cetre, Sylvain; Chun, Mark; Delorme, Jacques-Robert; Jovanovic, Nemanja; Lilley, Scott; Mawet, Dimitri; Ragland, Sam; Wetherell, Ed; Wizinowich, Peter (10 October 2019). "WISE J072003.20-084651.2B is a Massive T Dwarf". The Astronomical Journal. 158 (5): 174. arXiv:1908.06994. Bibcode:2019AJ....158..174D. doi:10.3847/1538-3881/ab3cd1. S2CID 201103740.
  4. ^ a b 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:1410.4288. Bibcode:2015AJ....149..104B. doi:10.1088/0004-6256/149/3/104. S2CID 45270145.
  5. ^ a b c Mamajek, Eric. "FAQ". Retrieved 2015-02-18.
  6. ^ 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 21 February 2015.
  7. ^ "2MASS J07200325-0846499". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2015-02-18.
  8. ^ 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:1508.06332. Bibcode:2015AJ....150..180B. doi:10.1088/0004-6256/150/6/180. S2CID 26828457.
  9. ^ "THE ONE HUNDRED NEAREST STAR SYSTEMS". RECONS (Research Consortium On Nearby Stars). Retrieved 2015-02-18.
  10. ^ a b de la Fuente Marcos, Raúl; de la Fuente Marcos, Carlos (10 May 2018). "An Independent Confirmation of the Future Flyby of Gliese 710 to the Solar System Using Gaia DR2". Research Notes of the AAS. 2 (2): 30. arXiv:1805.02644. Bibcode:2018RNAAS...2...30D. doi:10.3847/2515-5172/aac2d0. S2CID 119467738.
  11. ^ de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl; Aarseth, Sverre J. (6 February 2018). "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. 476 (1): L1–L5. arXiv:1802.00778. Bibcode:2018MNRAS.476L...1D. doi:10.1093/mnrasl/sly019.
  12. ^ Warren, Matt (2018-03-22). "Prehistoric visit from nearby star disturbed comets in our solar system". Science. Retrieved 2023-04-09.
  13. ^ Dvorsky, George (2018-03-21). "A Visiting Star Jostled Our Solar System 70,000 Years Ago". Gizmodo. Retrieved 2023-04-09.
  14. ^ de la Fuente Marcos, Raúl; de la Fuente Marcos, Carlos (28 July 2022). "The Closest Past Flyby of a Known Star to the Solar System: HD 7977, UCAC4 237-008148 or WISE J072003.20-084651.2?". Research Notes of the AAS. 6 (7): 152. Bibcode:2022RNAAS...6..152D. doi:10.3847/2515-5172/ac842b.