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WD 1145+017

Coordinates: Sky map 11h 48m 33.63s, +01° 28′ 59.4″
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WD 1145+017

A light curve for WD 1145+017 showing a dimming event, adapted from Xu et al. (2019).[1] The green dots are the data points and the blue line is the best fit model from the Xu et al. paper.
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Virgo[2]
Right ascension 11h 48m 33.62972s[3]
Declination +01° 28′ 59.4204″[3]
Apparent magnitude (V) 17.24±0.02[4]
Characteristics
Evolutionary stage White dwarf
Spectral type DB[5]
Astrometry
Proper motion (μ) RA: -43.664 mas/yr[3]
Dec.: -4.027 mas/yr[3]
Parallax (π)6.8534 ± 0.0907 mas[3]
Distance476 ± 6 ly
(146 ± 2 pc)
Details
Mass0.63±0.05[6] M☉
Radius0.012±0.001[4] R☉
Luminosity0.0088±0.0021[4] L☉
Surface gravity (log g)8.07±0.07[6] cgs
Temperature15,020±520[6] K
Age774±130[6] Myr
Other designations
WD 1145+017, EPIC 201563164[5]
Database references
SIMBADdata

WD 1145+017 (also known as EPIC 201563164[5]) is a white dwarf approximately 476 light-years (146 parsecs) from Earth in the constellation of Virgo. It is the first white dwarf to be observed with a transiting minor planet orbiting it.[7][8][9]

Stellar characteristics

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The white dwarf has a mass of 0.6 M☉, radius of 0.012 R☉ (1.34 R🜨) and a temperature of 15,020 K, typical for white dwarf stars. It has been a white dwarf for 224 million years.[6][10] The star's spectrum includes strong absorption lines due to magnesium, aluminium, silicon, calcium, iron and nickel. These elements commonly found in rocky planets are polluting the surface of the star, and would normally be expected to mix through the star and disappear from view after a million years.[10]

A circumstellar dust cloud and disk (likely due to disintegrating asteroids, located at 97 to 103 R_wd, and emitting thermal IR radiation) surrounds the star. In addition, a circumstellar gas disk (located ~ 25 to 40 R_wd, and undergoing relativistic precession with a period of ~ 5 years) surrounds the star as well.[1][11]

Based on 2018 studies and calculations, it is believed that the star initially was an early A-type main sequence star with a mass of about 2.48±0.14 M☉, remaining so for an estimated 550±100 million years.[6] Afterwards, following the exhaustion of hydrogen within its core, it evolved and expanded into a red giant before eventually ejecting its layers and contracting into a white dwarf, and has gradually cooled over the last 224±30 million years. This gives the star an estimated total age of around 774 million years.[6][12]

The apparent magnitude of the star, or how bright it appears from Earth's perspective, is about 17.[4] Therefore, it is too dim to be seen with the naked eye.

Planetary system

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The WD 1145+017 planetary system[4]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b ~0.000016 M🜨 ~0.0054 0.187454(4) — ~90° ~0.03 R🜨
Dusty disk 0.5? AU — —

The supposed planetesimal, WD 1145+017 b,[13] with a 4.5 hour orbit, is being ripped apart by the star and is a remnant of the former planetary system that the star hosted before becoming a white dwarf.[8][9] It is the first observation of a planetary object being shredded by a white dwarf. Several other large pieces have been seen in orbit as well. All the various larger pieces have orbits of 4.5 to 4.9 hours. Rocky material is raining down onto the star, and showing up in the star's spectrum. The system was detected by the Kepler space telescope in its extended K2 mission. Though the system was not a target of interest, it was within the field of view of observing sessions, and analysis of the observed data revealed the system.[14][15][16][17]

An excess of infrared radiation indicates that there is a dusty disk with a temperature of 1,150 K (880 °C).[10] Supporting observational data, along with data from the Chandra X-ray Observatory, were also found related to dust debris orbiting WD 1145+017.[18]

Similar systems

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In September 2020, astronomers reported the discovery, for the first time, of a very massive Jupiter-sized planet, named WD 1856+534 b, closely orbiting, every 36 hours, a tiny white dwarf star, named WD 1856+534, a left-over remnant of an earlier much larger Sun-like star.[19][20][21] This is the first true planet observed to transit a white dwarf, as opposed to the planetesimals transiting WD 1145+017.

See also

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Other planetesimals around white dwarfs:

References

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  1. ^ a b Xu, Siyi; et al. (24 April 2019). "Shallow Ultraviolet Transits of WD 1145+017". The Astronomical Journal. 157 (6): 255. arXiv:1904.10896. Bibcode:2019AJ....157..255X. doi:10.3847/1538-3881/ab1b36. S2CID 129945470.
  2. ^ Christopher Crockett (21 October 2015). "White dwarf upsets planetary system, consumes evidence".
  3. ^ a b c d Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  4. ^ a b c d e Rappaport, S.; Gary, B. L. (June 2016). "Drifting asteroid fragments around WD 1145+017". Monthly Notices of the Royal Astronomical Society. 458 (4): 3904–3917. arXiv:1602.00740. Bibcode:2016MNRAS.458.3904R. doi:10.1093/mnras/stw612.
  5. ^ a b c "WD 1145+017". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 25 October 2015.
  6. ^ a b c d e f g Izquierdo, P.; Rodríguez-Gil, P.; Gänsicke, B. T.; Mustill, A. J.; Toloza, O.; Tremblay, P. E.; Wyatt, M.; Chote, P.; Eggl, S.; Farihi, J.; Koester, D.; Lyra, W.; Manser, C. J.; Marsh, T. R.; Pallé, E.; Raddi, R.; Veras, D.; Villaver, E.; Zwart, S. Portegies (2018). "Fast spectrophotometry of WD 1145+017". Monthly Notices of the Royal Astronomical Society. 481 (1): 703–714. arXiv:1808.07320. Bibcode:2018MNRAS.481..703I. doi:10.1093/mnras/sty2315.
  7. ^ Andrew Vanderburg; John Asher Johnson; Saul Rappaport; Allyson Bieryla; Jonathan Irwin; John Arban Lewis; David Kipping; Warren R. Brown; Patrick Dufour; David R. Ciardi; Ruth Angus; Laura Schaefer; David W. Latham; David Charbonneau; Charles Beichman; Jason Eastman; Nate McCrady; Robert A. Wittenmyer; Jason T. Wright (11 June 2015). "A disintegrating minor planet transiting a white dwarf" (PDF). Nature. 526 (7574) (published 22 October 2015): 546–549. arXiv:1510.06387. Bibcode:2015Natur.526..546V. doi:10.1038/nature15527. PMID 26490620. S2CID 4451207.
  8. ^ a b Starr, Michelle (28 March 2020). "Necroplanetology: The Strangest Field of Astronomy You've Never Heard Of". ScienceAlert.com. Retrieved 30 March 2020.
  9. ^ a b Duvvuri, Girish M.; Redfield, Seth; Veras, Dimitri (18 March 2020). "Necroplanetology: Simulating the Tidal Disruption of Differentiated Planetary Material Orbiting WD 1145+017". The Astrophysical Journal. 893 (2): 166. arXiv:2003.08410. Bibcode:2020ApJ...893..166D. doi:10.3847/1538-4357/ab7fa0. S2CID 213004256.
  10. ^ a b c Bryce Croll; Paul A. Dalba; Andrew Vanderburg; Jason Eastman; Saul Rappaport; John DeVore; Allyson Bieryla; Philip S. Muirhead; Eunkyu Han; David W. Latham; Thomas G. Beatty; Robert A. Wittenmyer; Jason T. Wright; John Asher Johnson; Nate McCrady (8 October 2015). "Multiwavelength Transit Observations of the Candidate Disintegrating Planetesimals Orbiting WD 1145+017". The Astrophysical Journal. 836 (1): 82. arXiv:1510.06434. Bibcode:2017ApJ...836...82C. doi:10.3847/1538-4357/836/1/82. hdl:1721.1/109507. S2CID 37956928.
  11. ^ Gary, Bruce L. (10 June 2019). "6. White Dwarf WD 1145+017 Photometric Monitoring Observations by Amateur Observers B. Gary & T. Kaye". Bruce L. Gary. Retrieved 13 June 2019.
  12. ^ Veras, Dimitri (2016). "Post-main-sequence planetary system evolution". Royal Society Open Science. 3 (2): 150571. arXiv:1601.05419. Bibcode:2016RSOS....350571V. doi:10.1098/rsos.150571. PMC 4785977. PMID 26998326.
  13. ^ "Planet WD 1145+017 b". Extrasolar Planets Encyclopaedia. Retrieved 30 October 2015.
  14. ^ Ian O'Neill (21 October 2015). "Caught in the Act: White Dwarf is Killing a Planet". Discovery Channel. Archived from the original on 10 March 2016. Retrieved 30 October 2015.
  15. ^ Michael D. Lemonick (21 October 2015). "Zombie Star Caught Feasting On Asteroids". National Geographic. Archived from the original on October 24, 2015.
  16. ^ "NASA's Kepler K2 Mission Discovers Planet-Destroying White Dwarf Star". Sci-News.com. 22 October 2015.
  17. ^ Camille M. Carlisle (26 October 2015). "White Dwarf Eats Mini Planet?". Sky and Telescope.
  18. ^ Rappaport, S.; Gary, B.L.; Vanderburg, A.; Xu, S.; Pooley, D.; Mukai, K. (24 September 2017). "WD 1145+017: Optical Activity During 2016-2017 and Limits on the X-Ray Flux". Monthly Notices of the Royal Astronomical Society. 474 (1): 933. arXiv:1709.08195. Bibcode:2018MNRAS.474..933R. doi:10.1093/mnras/stx2663.
  19. ^ Vanderburg, Andrew; et al. (16 September 2020). "A giant planet candidate transiting a white dwarf". Nature. 585 (7825): 363–367. arXiv:2009.07282. Bibcode:2020Natur.585..363V. doi:10.1038/s41586-020-2713-y. hdl:1721.1/129733. PMID 32939071. S2CID 221738865. Retrieved 17 September 2020.
  20. ^ Chou, felicia; Andreoli, Claire; Cofield, Calia (16 September 2020). "NASA Missions Spy First Possible Planet Hugging a Stellar Cinder". NASA. Retrieved 17 September 2020.
  21. ^ Gary, Bruce L. (17 September 2020). "WD 1856+534 Transit Light Curve Photometry". BruceGary.net. Retrieved 17 September 2020.
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