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Observation data Epoch J2000.0 [1] Equinox J2000.0 [1] |
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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 |
Distance | approx. 20 ly (approx. 6 pc) |
Absolute magnitude (MV) | 19.4[4] |
Details | |
Mass | 0.15[2] M☉ |
Age | 3–10 billion[2] years |
Other designations | |
Database references | |
SIMBAD | data |
Scholz's star (WISE designation WISE 0720−0846 or fully WISE J072003.20−084651.2) is a 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] The primary is a red dwarf with a stellar classification of M±1 and has 9±2 86Jupiter masses.[2] The secondary is probably a T5 brown dwarf with ±12 Jupiter masses. 65[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.
Distance
Source | Parallax, mas | Distance, pc | Distance, ly | Distance, Pm | Ref. |
---|---|---|---|---|---|
Scholz (2014) | 142±38 | 7+2.6 −1.5 |
23+8.4 −4.8 |
217.3+79.4 −45.9 |
[7] |
Scholz (2014) | 5.0±1.2[nb 1] | 16.3±3.9 | 154.3±37 | [7] | |
Scholz (2014) | ~ 6.0[nb 2] | ~ 19.6 | ~ 185.1 | [7] | |
Scholz (2014) | ~ 6.6[nb 3] | ~ 21.5 | ~ 203.7 | [7] | |
Scholz (2014) | ~ 6.0[nb 4] | ~ 19.6 | ~ 185.1 | [7] | |
Scholz (2014) | ~ 6.5[nb 5] | ~ 21.2 | ~ 200.6 | [7] | |
Scholz (2014) | ~ 8.4[nb 6] | ~ 27.4 | ~ 259.2 | [7] | |
Scholz (2014) | 6.5±1.5[nb 7] | 21.2±4.9 | 200.6±46.3 | [7] | |
Burgasser et al. (2015) | 166±28 | 6+1.2 −0.9 |
19.6+4 −2.8 |
185.9+37.7 −26.8 |
[3][2] |
Ivanov et al. (2015) | 6.07+1.36 −0.95 |
19.8+4.4 −3.1 |
187.3+42 −29.3 |
[8] |
Non-trigonometric distance estimates are marked in italic. The most precise estimate is marked in bold.
Proper motion
Scholz's star proper motion estimates
Source | μ, mas/yr | P. A., ° | μRA, mas/yr | μDEC, mas/yr | Ref. |
---|---|---|---|---|---|
Monet et al. (2003) | 108 ± 30 | 199.4 ± 11.3 | −36 ± 13 | −102 ± 27 | [7] |
Röser et al. (2010) | 114 ± 9 | 200 ± 4.5 | −39 ± 7 | −107 ± 7 | [7] |
Scholz (2014) | 123 ± 2.6 | 199.5 ± 1.2 | −41 ± 2 | −116 ± 2 | [7] |
Burgasser et al. (2015) | 121.7 ± 0.4 | 199.34 ± 0.15 | −40.3 ± 0.2 | −114.8 ± 0.4 | [3][2] |
Ivanov et al. (2015) | 118.4 ± 2.5 | 199.3 ± 1.3 | −39.1 ± 2.1 | −111.8 ± 1.9 | [8] |
The most accurate estimates are marked in bold. Italic are computed values, not italic are values, given in the sources.
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] In a simulation, 98% of the test objects had the system pass 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 be 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
- ^ a b c d e f "2MASS J07200325-0846499 -- Brown Dwarf Candidate". SIMBAD. Retrieved 2015-02-18.
- ^ 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:1502.04655. Bibcode:2015ApJ...800L..17M. doi:10.1088/2041-8205/800/1/L17.
- ^ a b c d e 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.
- ^ a b c Mamajek, Eric. "FAQ". Retrieved 2015-02-18.
- ^ 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.
- ^ "THE ONE HUNDRED NEAREST STAR SYSTEMS". RECONS (Research Consortium On Nearby Stars). Retrieved 2015-02-18.
- ^ a b c d e f g h i j k Scholz, R.-D. (2014). "Neighbours hiding in the Galactic plane, a new M/L dwarf candidate for the 8 pc sample". Astronomy & Astrophysics 561: A113. arXiv:1311.2716. Bibcode:2014A&A...561A.113S. doi:10.1051/0004-6361/201323015.
- ^ a b Ivanov, V. D.; Vaisanen, P.; Kniazev, A. Y.; Beletsky, Y.; Mamajek, E. E.; Mužić, K.; Beamín, J. C.; Boffin, H. M. J.; Pourbaix, D.; Gandhi, P.; Gulbis, A.; Monaco, L.; Saviane, I.; Kurtev, R.; Mawet, D.; Borissova, J.; Minniti, D. (2015). "Properties of the solar neighbor WISE J072003.20-084651.2". Astronomy & Astrophysics 574: A64. arXiv:1410.6792. Bibcode:2015A&A...574A..64I. doi:10.1051/0004-6361/201424883.
Notes
- ^ Photometric distance based on comparison with absolute J and w2 magnitudes of LP 944-20.
- ^ Photometric distance applying the spectral type/absolute magnitude relations of Dupuy & Liu (2012) to spectral type L0.
- ^ Photometric distance applying the spectral type/absolute magnitude relations of Dupuy & Liu (2012) to spectral type M9.5.
- ^ Photometric distance applying the spectral type/absolute magnitude relations of Dupuy & Liu (2012) to spectral type M9.
- ^ Photometric distance applying the spectral type/absolute magnitude relations of Dupuy & Liu (2012) to spectral type M8.5.
- ^ Photometric distance applying the spectral type/absolute magnitude relations of Dupuy & Liu (2012) to spectral type M8.
- ^ Adopted distance.
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