WD 1145+017

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]

WD 1145+017
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Virgo[1]
Right ascension  11h 48m 33.63s[2]
Declination +01° 28′ 59.4″[2]
Apparent magnitude (V) 17.0[3]
Characteristics
Spectral type DB[2]
Astrometry
Distance570[4] ly
(174.0[3] pc)
Details
Mass0.63±0.05[5] M☉
Radius0.02[6] R☉
Temperature15900 ± 500[3]
15020±520[5] K
Metallicity [Fe/H]~0.1 dex
Age0.224±0.030[5] Gyr
Other designations
WD 1145+017,[2] EPIC 201563164[3]
Database references
SIMBADdata

Stellar characteristics

The white dwarf has a mass of 0.6 M☉, radius of 0.02 R☉ (1.4 R⊕) and a temperature of 15,900 K, typical for white dwarf stars. It has been a white dwarf for 175 million years.[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 its mass, the star was likely an early F-type main sequence star (spectral type F0) before it became a red giant.[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]

See also

References
  1. Christopher Crockett (21 October 2015). "White dwarf upsets planetary system, consumes evidence".
  2. "WD 1145+017". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 25 October 2015.
  3. "Planet WD 1145+017 b". The Extrasolar Planet Encyclopedia. Retrieved 30 October 2015.
  4. Christine Pulliam (21 October 2015). "Cosmic "Death Star" is Destroying a Planet". Harvard-Smithsonian Center for Astrophysics. 2015–21.
  5. 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.
  6. 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 (published 22 October 2015). 526 (7574): 546–549. arXiv:1510.06387. Bibcode:2015Natur.526..546V. doi:10.1038/nature15527. PMID 26490620.
  7. Starr, Michelle (28 March 2020). "Necroplanetology: The Strangest Field of Astronomy You've Never Heard Of". ScienceAlert.com. Retrieved 30 March 2020.
  8. Duvvuri, Girish M.; Redfield, Seth; Veras, Dimitri (18 March 2020). "Necroplanetology: Simulating the Tidal Disruption of Differentiated Planetary Material Orbiting WD 1145+017". arXiv:2003.08410 [astro-ph.EP].
  9. 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.
  10. 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.
  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. Ian O'Neill (21 October 2015). "Caught in the Act: White Dwarf is Killing a Planet". Discovery Channel.
  14. Michael D. Lemonick (21 October 2015). "Zombie Star Caught Feasting On Asteroids". National Geographic.
  15. "NASA's Kepler K2 Mission Discovers Planet-Destroying White Dwarf Star". Sci-News.com. 22 October 2015.
  16. Camille M. Carlisle (26 October 2015). "White Dwarf Eats Mini Planet?". Sky and Telescope.
  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. arXiv:1709.08195. Bibcode:2018MNRAS.474..933R. doi:10.1093/mnras/stx2663.
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