Astronomy:AR Scorpii
300px Artist’s representation of AR Scorpii system | |
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Scorpius |
| Right ascension | 16h 21m 47.29576s[1] |
| Declination | −22° 53′ 11.3164″[1] |
| Characteristics | |
| Apparent magnitude (G) | 13.6 - 16.9[2] |
| White dwarf | |
| Evolutionary stage | White dwarf |
| Red dwarf | |
| Evolutionary stage | Main sequence |
| Spectral type | M5[3] |
| Astrometry | |
| Proper motion (μ) | RA: +9.48+0.04 −0.07[1] mas/yr Dec.: −51.32+0.22 −0.38[1] mas/yr |
| Parallax (π) | 8.52 ± 0.07[1] mas |
| Distance | 383 ± 3 ly (117.4 ± 1.0 pc) |
| Details | |
| White dwarf | |
| Mass | 1.0±0.1[1] M☉ |
| Radius | 0.01[4] R☉ |
| Radius | 7000[4] km |
| Rotation | 1.95[3] minutes |
| Red dwarf | |
| Mass | 0.31[1][5] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
AR Scorpii (AR Sco) is a binary star system that consists of a pulsar-like white dwarf and a red dwarf star.[3] It is located close to the ecliptic plane in the constellation Scorpius. Parallax measurements made with very-long-baseline interferometry put the system at a distance of about 117.4 parsecs (383 light-years).[1]
File:Artist’s impression video of the exotic binary star system AR Scorpii (video).webm
In 1904 Henrietta Swan Leavitt and Edward Charles Pickering announced the discovery of this variable star.[6] It was given its variable star designation, AR Scorpii, in 1914.[7]
Observations
AR Scorpii is the first "white dwarf-pulsar" to be discovered.[9] Its unusual nature was first noticed by amateur astronomers.[10] The 3.56-hour period in AR Scorpii's light curve caused it to be misclassified as a Delta Scuti variable, but in 2016, this period was found to be the binary orbital period. In addition, the system shows very strong optical, ultraviolet, and radio pulsations originating from the red dwarf with a period of just 1.97 minutes, which is a beat period from the orbital rotation and the white dwarf spin.[3] These pulsations occur when a relativistic beam from the white dwarf sweeps across the red dwarf, which then reprocesses the beam into the observed electromagnetic energy. Although the white dwarf shows evidence of accretion in the past, at present it is not accreting significantly, and the system is powered by the spin-down of the white dwarf.[9][4] The white dwarf's rotation will slow down on a timescale of 107 years.[4] It has a radius of about 7×103 km,[4] about the same size as Earth.
See also
- AE Aquarii - the first discovered white dwarf pulsar.
- Pulsar-like white dwarfs
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Jiang, Pengfei; Cui, Lang; Yang, Jun; Zhang, Bo; Xu, Shuangjing; Shu, Fengchun; Jiang, Wu; Chen, Wen et al. (2023-02-07). "VLBI astrometry on the white dwarf pulsar AR Scorpii". Monthly Notices of the Royal Astronomical Society 520 (2): 2942–2951. doi:10.1093/mnras/stad327. ISSN 0035-8711.
- ↑ "AR Scorpii". AAVSO. https://www.aavso.org/vsx/index.php?view=detail.top&oid=32887.
- ↑ 3.0 3.1 3.2 3.3 Marsh, T. R. (2016). "A radio-pulsing white dwarf binary star". Nature 537 (7620): 374–377. doi:10.1038/nature18620. PMID 27462808. Bibcode: 2016Natur.537..374M.
- ↑ 4.0 4.1 4.2 4.3 4.4 Singh, K. K.; Meintjes, P. J.; Yadav, K. K. (2021). "Properties of white dwarf in the binary system AR Scorpii and its observed features". Modern Physics Letters A 36 (13). doi:10.1142/S0217732321500966. Bibcode: 2021MPLA...3650096S.
- ↑ 5.0 5.1 Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E. et al. (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. http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=II/246.
- ↑ Leavitt, Henrietta S.; Pickering, Edward C. (December 1904). "106 New Variable Stars in Scorpius". Harvard College Observatory Circular 90: 1–4. Bibcode: 1904HarCi..90....1L. https://articles.adsabs.harvard.edu/pdf/1904HarCi..90....1L. Retrieved 18 September 2025.
- ↑ Dunér, Nils Christofer; Hartwig, Ernst; Müller, G. (September 1914). "Benennung von neu entdeckten veränderlichen Sternen (in German)". Astronomische Nachrichten 199 (5): 65–88. doi:10.1002/asna.19141990502. https://articles.adsabs.harvard.edu/pdf/1914AN....199...65D.
- ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html.
- ↑ 9.0 9.1 Buckley, D. A. H.; Meintjes, P. J.; Potter, S. B.; Marsh, T. R.; Gänsicke, B. T. (2017-01-23). "Polarimetric evidence of a white dwarf pulsar in the binary system AR Scorpii". Nature Astronomy 1 (2): 0029. doi:10.1038/s41550-016-0029. Bibcode: 2017NatAs...1E..29B.
- ↑ Hambsch, Franz-Josef (15 August 2016). "Amateurs Help Discover Pulsing White Dwarf". Sky and Telescope. http://www.skyandtelescope.com/observing/stargazers-corner/amateurs-aid-discovery-pulsing-white-dwarf-ar-scorpii/.
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