Astronomy:WD 1145+017

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Short description: White dwarf in the constellation of Virgo

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

WD 1145+017
Observation data
Equinox J2000.0]] (ICRS)
Constellation Virgo[1]
Right ascension  11h 48m 33.63s[2]
Declination +01° 28′ 59.4″[2]
Apparent magnitude (V) 17.0[3]
Characteristics
Evolutionary stage White dwarf
Spectral type DB[2]
Astrometry
Distance570[4] ly
(174.0[3] pc)
Details
Mass0.63 ± 0.05[5] M☉
Radius0.013[6] R☉
Temperature15,020 ± 520[5] K
Metallicity [Fe/H]~0.1 dex
Age774 ± 130[5] Myr
Other designations
WD 1145+017,[2] EPIC 201563164[3]
Database references
SIMBADdata

WD 1145+017[2] (also known as EPIC 201563164[3]) is a white dwarf approximately 570 light-years (170 pc) from Earth in the constellation of Virgo. It is the first white dwarf to be observed with a transiting planetary-mass object orbiting it.[7][8]

Stellar characteristics

The white dwarf has a mass of 0.6 M☉, radius of 0.013 R☉ (1.4 R⊕) and a temperature of 15,020 K, typical for white dwarf stars. It has been a white dwarf for 224 million years.[5][9] The star included 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.[9]

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.[10][11]

Based on recent studies and calculations, it is believed that the star initially was an early A-type main sequence star with a mass of about 2.46 M☉, remaining so for an estimated 550 million years.[5] 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 million years. This gives the star an estimated total age of around 774 million years.[5][12]

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

Planetary system

The WD 1145+017 planetary system[3]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b 0.0006678 M⊕ ~0.005 0.1875 ± 0.04 — ~89° ~0.15 R⊕
Dusty disk 0.5? AU — —

The supposed planetesimal, WD 1145+017 b,[3] 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.[7][8] 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.[13][14][15][16]

An excess of infrared radiation indicates that there is a dusty disk with a temperature of 1,150 K (880 °C).[9] Supporting observational data, along with data from the Chandra X-ray Observatory, were also found related to dust debris orbiting WD 1145+017.[17]

Similar systems

In September 2020, astronomers reported the discovery, for the first time, of a very massive Jupiter-sized planet, named WD 1856 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.[18][19][20] This WD 1856 system is similar to the WD 1145+017 system.

See also

References

  1. ↑ Christopher Crockett (21 October 2015). "White dwarf upsets planetary system, consumes evidence". https://www.sciencenews.org/blog/science-ticker/white-dwarf-upsets-planetary-system-consumes-evidence. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 "WD 1145+017". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=WD+1145%2B017. 
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 "Planet WD 1145+017 b". Extrasolar Planets Encyclopaedia. https://exoplanet.eu/catalog/wd_1145_017_b--2456/. 
  4. ↑ Christine Pulliam (21 October 2015). "Cosmic "Death Star" is Destroying a Planet". Harvard-Smithsonian Center for Astrophysics. https://www.cfa.harvard.edu/news/2015-21. 
  5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 Izquierdo, P.; Rodríguez-Gil, P.; Gänsicke, B. T.; Mustill, A. J.; Toloza, O.; Tremblay, P. E.; Wyatt, M.; Chote, P. et al. (2018). "Fast spectrophotometry of WD 1145+017". Monthly Notices of the Royal Astronomical Society 481 (1): 703–714. doi:10.1093/mnras/sty2315. Bibcode: 2018MNRAS.481..703I. 
  6. ↑ Andrew Vanderburg; John Asher Johnson; Saul Rappaport; Allyson Bieryla; Jonathan Irwin; John Arban Lewis; David Kipping; Warren R. Brown et al. (11 June 2015). "A disintegrating minor planet transiting a white dwarf". Nature 526 (7574): 546–549. 22 October 2015. doi:10.1038/nature15527. PMID 26490620. Bibcode: 2015Natur.526..546V. https://www.cfa.harvard.edu/~avanderb/wd1145_017.pdf. 
  7. ↑ 7.0 7.1 Starr, Michelle (28 March 2020). "Necroplanetology: The Strangest Field of Astronomy You've Never Heard Of". ScienceAlert.com. https://www.sciencealert.com/necroplanetology-the-study-of-planets-dismembered-remains. 
  8. ↑ 8.0 8.1 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. doi:10.3847/1538-4357/ab7fa0. Bibcode: 2020ApJ...893..166D. 
  9. ↑ 9.0 9.1 9.2 Bryce Croll; Paul A. Dalba; Andrew Vanderburg; Jason Eastman; Saul Rappaport; John DeVore; Allyson Bieryla; Philip S. Muirhead et al. (8 October 2015). "Multiwavelength Transit Observations of the Candidate Disintegrating Planetesimals Orbiting WD 1145+017". The Astrophysical Journal 836 (1): 82. doi:10.3847/1538-4357/836/1/82. Bibcode: 2017ApJ...836...82C. 
  10. ↑ Xu, Siyi (24 April 2019). "Shallow Ultraviolet Transits of WD 1145+017". The Astronomical Journal 157 (6): 255. doi:10.3847/1538-3881/ab1b36. Bibcode: 2019AJ....157..255X. 
  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. http://www.brucegary.net/zombie6/. 
  12. ↑ Veras, Dimitri (2016). "Post-main-sequence planetary system evolution". Royal Society Open Science 3 (2): 150571. doi:10.1098/rsos.150571. PMID 26998326. Bibcode: 2016RSOS....350571V. 
  13. ↑ Ian O'Neill (21 October 2015). "Caught in the Act: White Dwarf is Killing a Planet". Discovery Channel. http://news.discovery.com/space/astronomy/caught-in-the-act-white-dwarf-is-killing-a-planet-151021.htm. 
  14. ↑ Michael D. Lemonick (21 October 2015). "Zombie Star Caught Feasting On Asteroids". National Geographic. http://news.nationalgeographic.com/2015/10/151021-zombie-dead-star-eats-asteroid-astronomy/. 
  15. ↑ "NASA's Kepler K2 Mission Discovers Planet-Destroying White Dwarf Star". Sci-News.com. 22 October 2015. http://www.sci-news.com/astronomy/science-kepler-wd-1145-017-white-dwarf-03366.html. 
  16. ↑ Camille M. Carlisle (26 October 2015). "White Dwarf Eats Mini Planet?". Sky and Telescope. http://www.skyandtelescope.com/astronomy-news/white-dwarf-eats-planet2610201523/. 
  17. ↑ 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. doi:10.1093/mnras/stx2663. Bibcode: 2018MNRAS.474..933R. 
  18. ↑ Vanderburg, Andrew (16 September 2020). "A giant planet candidate transiting a white dwarf". Nature 585 (7825): 363–367. doi:10.1038/s41586-020-2713-y. PMID 32939071. Bibcode: 2020Natur.585..363V. https://www.nature.com/articles/s41586-020-2713-y. Retrieved 17 September 2020. 
  19. ↑ Chou, felicia; Andreoli, Claire; Cofield, Calia (16 September 2020). "NASA Missions Spy First Possible Planet Hugging a Stellar Cinder". NASA. https://www.jpl.nasa.gov/news/news.php?feature=7746. 
  20. ↑ Gary, Bruce L. (17 September 2020). "WD 1856+534 Transit Light Curve Photometry". BruceGary.net. http://www.brucegary.net/wd1856/. 

External links



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