View source for Astronomy:WD 1145+017

{{Short description|White dwarf in the constellation of Virgo}}
{{sky|11|48|33.63|+|01|28|59.4|567}}
{{Starbox begin
| name = WD 1145+017
}}
{{Starbox observe
| constell = [[Astronomy:Virgo (constellation)|Virgo]]<ref name=ScienceNews-2015-10-21>{{cite news |url= https://www.sciencenews.org/blog/science-ticker/white-dwarf-upsets-planetary-system-consumes-evidence |title= White dwarf upsets planetary system, consumes evidence |author= Christopher Crockett |date= 21 October 2015 }}</ref>
| epoch = [[Astronomy:J2000.0|J2000.0]]
| ra = {{RA|11|48|33.63}}<ref name=SIMBAD />
| dec = {{DEC|+01|28|59.4}}<ref name=SIMBAD />
| appmag_v = 17.0<ref name=EPeu>{{cite web |url= https://exoplanet.eu/catalog/wd_1145_017_b--2456/ |work= [[Astronomy:Extrasolar Planets Encyclopaedia|Extrasolar Planets Encyclopaedia]] |title= Planet WD 1145+017 b |access-date= 30 October 2015 }}</ref>
}}
{{Starbox character
| type = [[Astronomy:White dwarf|White dwarf]]
| class = [[Astronomy:Stellar classification#White dwarf classification|DB]]<ref name=SIMBAD>{{cite simbad |title= WD 1145+017 |access-date= 25 October 2015 }}</ref>
}}
{{Starbox astrometry
| dist_pc = 174.0<ref name=EPeu />
| dist_ly = 570<ref name=CfA-2015-21>{{cite web |url= https://www.cfa.harvard.edu/news/2015-21 |title= Cosmic "Death Star" is Destroying a Planet |date= 21 October 2015 |id= 2015–21 |author= Christine Pulliam |publisher= Harvard-Smithsonian Center for Astrophysics }}</ref>
}}
{{Starbox detail
| mass = 0.63 ± 0.05<ref name="august2018study"/>
| radius = 0.013<ref name="discovery">{{cite journal |title= A disintegrating minor planet transiting a white dwarf |author1=Andrew Vanderburg |author2=John Asher Johnson |author3=Saul Rappaport |author4=Allyson Bieryla |author5=Jonathan Irwin |author6=John Arban Lewis |author7=David Kipping |author8=Warren R. Brown |author9=Patrick Dufour |author10=David R. Ciardi |author11=Ruth Angus |author12=Laura Schaefer |author13=David W. Latham |author14=David Charbonneau |author15=Charles Beichman |author16=Jason Eastman |author17=Nate McCrady |author18=Robert A. Wittenmyer |author19=Jason T. Wright |arxiv= 1510.06387 |bibcode= 2015Natur.526..546V |doi= 10.1038/nature15527 |url= https://www.cfa.harvard.edu/~avanderb/wd1145_017.pdf |date= 11 June 2015 |publication-date= 22 October 2015 |journal= Nature |volume= 526 |issue=7574 |pages= 546–549 |pmid=26490620|s2cid=4451207 }}</ref>
| temperature =15,020 ± 520<ref name="august2018study">{{cite journal |last1=Izquierdo |first1=P. |last2=Rodríguez-Gil |first2=P. |last3=Gänsicke |first3=B. T. |last4=Mustill |first4=A. J. |last5=Toloza |first5=O. |last6=Tremblay |first6=P. E. |last7=Wyatt |first7=M. |last8=Chote |first8=P. |last9=Eggl |first9=S. |last10=Farihi |first10=J. |last11=Koester |first11=D. |last12=Lyra |first12=W. |last13=Manser |first13=C. J. |last14=Marsh |first14=T. R. |last15=Pallé |first15=E. |last16=Raddi |first16=R. |last17=Veras |first17=D. |last18=Villaver |first18=E. |last19=Zwart |first19=S. Portegies |title=Fast spectrophotometry of WD 1145+017 |journal=Monthly Notices of the Royal Astronomical Society |volume=481 |issue=1 |pages=703–714 |arxiv=1808.07320 |bibcode=2018MNRAS.481..703I |doi=10.1093/mnras/sty2315 |year=2018 }}</ref>
| metal_fe = ~0.1
| age_myr = 774 ± 130<ref name="august2018study"/>
}}
{{Starbox catalog
| names = [[Astronomy:White dwarf|WD]]&nbsp;1145+017,<ref name=SIMBAD /> [[Astronomy:Ecliptic Plane Input Catalog|EPIC]]<!-- Kepler K2 input catalog -->&nbsp;201563164<ref name=EPeu />
}}
{{Starbox reference
| Simbad = EPIC+201563164
}}
{{Starbox end}}
'''WD 1145+017'''<ref name=SIMBAD /> (also known as '''EPIC 201563164'''<ref name=EPeu />) is a [[Astronomy:White dwarf|white dwarf]] approximately {{convert|570|ly|pc}} from [[Astronomy:Earth|Earth]] in the [[Astronomy:Constellation|constellation]] of [[Astronomy:Virgo (constellation)|Virgo]]. It is the first white dwarf to be observed with a transiting [[Astronomy:Planetary-mass object|planetary-mass object]] orbiting it.<ref name="SA-20200328" /><ref name="ARX-20200318" />

== Stellar characteristics ==
The white dwarf has a mass of 0.6 {{solar mass}}, radius of 0.013 {{solar radius}} (1.4 {{Earth radius}}) and a temperature of 15,020 [[Kelvin|K]], typical for white dwarf stars. It has been a white dwarf for 224 million years.<ref name=august2018study/><ref name=croll>{{cite journal|title= Multiwavelength Transit Observations of the Candidate Disintegrating Planetesimals Orbiting WD 1145+017 |author1=Bryce Croll |author2=Paul A. Dalba |author3=Andrew Vanderburg |author4=Jason Eastman |author5=Saul Rappaport |author6=John DeVore |author7=Allyson Bieryla |author8=Philip S. Muirhead |author9=Eunkyu Han |author10=David W. Latham |author11=Thomas G. Beatty |author12=Robert A. Wittenmyer |author13=Jason T. Wright |author14=John Asher Johnson |author15=Nate McCrady |arxiv=1510.06434|date= 8 October 2015 |doi=10.3847/1538-4357/836/1/82 |volume=836 |issue=1 |journal=The Astrophysical Journal |page=82|bibcode = 2017ApJ...836...82C |hdl=1721.1/109507 |s2cid=37956928 |doi-access=free }}</ref> The star included strong absorption lines due to [[Chemistry:Magnesium|magnesium]], [[Chemistry:Aluminium|aluminium]], [[Chemistry:Silicon|silicon]], [[Chemistry:Calcium|calcium]], [[Chemistry:Iron|iron]] and [[Chemistry:Nickel|nickel]]. These elements commonly found in [[Astronomy:Terrestrial planet|rocky planets]] are polluting the surface of the star, and would normally be expected to [[Astronomy:Convection|mix through the star]] and disappear from view after a million years.<ref name=croll/>

A circumstellar dust cloud and disk (likely due to disintegrating [[Astronomy:Asteroid|asteroid]]s, 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 [[Physics:Precession|precession]] with a period of ~ 5 years) surrounds the star as well.<ref name="ARX_20190424">{{cite journal |author=Xu, Siyi |display-authors=et al |title=Shallow Ultraviolet Transits of WD 1145+017 |journal=The Astronomical Journal |date=24 April 2019 |volume=157 |issue=6 |pages=255 |doi=10.3847/1538-3881/ab1b36 |arxiv=1904.10896|bibcode=2019AJ....157..255X |s2cid=129945470 |doi-access=free }}</ref><ref name="BLG-20190613">{{cite web |last=Gary |first=Bruce L. |title=6. White Dwarf WD 1145+017 Photometric Monitoring Observations by Amateur Observers B. Gary & T. Kaye |url=http://www.brucegary.net/zombie6/ |date=10 June 2019 |work=Bruce L. Gary |access-date=13 June 2019 }}</ref>

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 {{solar mass}}, remaining so for an estimated 550 million years.<ref name=august2018study/> Afterwards, following the exhaustion of hydrogen within its core, it evolved and expanded into a [[Astronomy:Red giant|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.<ref name=august2018study/><ref name="ppe">{{Cite journal|arxiv=1601.05419|last1=Veras|first1=Dimitri|title=Post-main-sequence planetary system evolution|journal=Royal Society Open Science|volume=3|issue=2|pages=150571|year=2016|bibcode=2016RSOS....350571V|doi=10.1098/rsos.150571|pmid=26998326|pmc=4785977}}</ref>

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 ==
{{OrbitboxPlanet begin
| name = WD 1145+017
| table_ref=<ref name=EPeu/>
}}
{{OrbitboxPlanet
| exoplanet = [[Astronomy:WD 1145+017 b|b]]
| mass_earth = 0.0006678
| period = 0.1875 ± 0.04
| semimajor = ~0.005
| radius_earth = ~0.15
| inclination = ~89
}}
{{OrbitboxPlanet disk
| disk = Dusty disk
| periapsis = 0.5? 
| apoapsis =
| inclination = 
}}
{{Orbitbox end}}
The supposed planetesimal, [[Astronomy:WD 1145+017 b|WD 1145+017 b]],<ref name=EPeu /> with a 4.5 hour orbit, is being [[Physics:Roche limit|ripped apart]] by the star and is a remnant of the former [[Astronomy:Planetary system|planetary system]] that the star hosted before becoming a white dwarf.<ref name="SA-20200328">{{cite news |last=Starr |first=Michelle |title=Necroplanetology: The Strangest Field of Astronomy You've Never Heard Of |url=https://www.sciencealert.com/necroplanetology-the-study-of-planets-dismembered-remains |date=28 March 2020 |work=ScienceAlert.com |access-date=30 March 2020 }}</ref><ref name="ARX-20200318">{{cite journal |last1=Duvvuri |first1=Girish M. |last2=Redfield |first2=Seth |last3=Veras |first3=Dimitri |title=Necroplanetology: Simulating the Tidal Disruption of Differentiated Planetary Material Orbiting WD 1145+017 |journal=The Astrophysical Journal |date=18 March 2020 |volume=893 |issue=2 |page=166 |doi=10.3847/1538-4357/ab7fa0 |arxiv=2003.08410 |bibcode=2020ApJ...893..166D |s2cid=213004256 |doi-access=free }}</ref> 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 [[Engineering:Kepler (spacecraft)|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.<ref name=Discovery-2015-10-21>{{cite news |url= http://news.discovery.com/space/astronomy/caught-in-the-act-white-dwarf-is-killing-a-planet-151021.htm |title= Caught in the Act: White Dwarf is Killing a Planet |date= 21 October 2015 |author= Ian O'Neill |publisher= Discovery Channel |access-date= 30 October 2015 |archive-date= 10 March 2016 |archive-url= https://web.archive.org/web/20160310014642/http://news.discovery.com/space/astronomy/caught-in-the-act-white-dwarf-is-killing-a-planet-151021.htm |url-status= dead }}</ref><ref name=NatGeo-2015-10-21>{{cite news |url= http://news.nationalgeographic.com/2015/10/151021-zombie-dead-star-eats-asteroid-astronomy/ |archive-url= https://web.archive.org/web/20151024081958/http://news.nationalgeographic.com/2015/10/151021-zombie-dead-star-eats-asteroid-astronomy/ |url-status= dead |archive-date= October 24, 2015 |title= Zombie Star Caught Feasting On Asteroids |author= Michael D. Lemonick |date= 21 October 2015 |publisher= National Geographic }}</ref><ref name=SciNews-2015-10-22>{{cite news |url= http://www.sci-news.com/astronomy/science-kepler-wd-1145-017-white-dwarf-03366.html |title= NASA's Kepler K2 Mission Discovers Planet-Destroying White Dwarf Star |date= 22 October 2015 |publisher= Sci-News.com }}</ref><ref name=S&T-2015-10-26>{{cite news |url= http://www.skyandtelescope.com/astronomy-news/white-dwarf-eats-planet2610201523/ |title= White Dwarf Eats Mini Planet? |author= Camille M. Carlisle |date= 26 October 2015 |publisher= Sky and Telescope }}</ref>

An excess of [[Physics:Infrared radiation|infrared radiation]] indicates that there is a dusty disk with a temperature of {{convert|1150|K|C}}.<ref name=croll/> Supporting observational data, along with data from the [[Astronomy:Chandra X-ray Observatory|Chandra X-ray Observatory]], were also found related to dust debris orbiting WD 1145+017.<ref name="arXiv-20170924">{{Cite journal|last1=Rappaport |first1=S. |last2=Gary |first2=B.L. |last3=Vanderburg |first3=A. |last4=Xu |first4=S. |last5=Pooley |first5=D. |last6=Mukai |first6=K. |title=WD 1145+017: Optical Activity During 2016-2017 and Limits on the X-Ray Flux |journal=Monthly Notices of the Royal Astronomical Society |volume=474 |issue=1 |pages=933 |date=24 September 2017 |arxiv=1709.08195 |doi=10.1093/mnras/stx2663 |bibcode=2018MNRAS.474..933R }}</ref>

== Similar systems ==
In September 2020, astronomers reported the discovery, for the first time, of a very massive [[Astronomy:Jupiter|Jupiter-sized planet]], named WD 1856 b, closely orbiting, every 36 hours, a tiny [[Astronomy:White dwarf|white dwarf star]], named [[Astronomy:WD 1856+534|WD 1856+534]], a left-over remnant of an earlier much larger [[Astronomy:Sun|sun-like star]].<ref name="NAT-20200916">{{cite journal |author=Vanderburg, Andrew |display-authors=et al. |title=A giant planet candidate transiting a white dwarf |url=https://www.nature.com/articles/s41586-020-2713-y |date=16 September 2020 |journal=Nature |volume=585 |issue=7825 |pages=363–367 |doi=10.1038/s41586-020-2713-y |arxiv=2009.07282  |pmid=32939071 |bibcode=2020Natur.585..363V |access-date=17 September 2020 |hdl=1721.1/129733 |s2cid=221738865 |hdl-access=free }}</ref><ref name="NASA-20200916">{{cite news |last1=Chou |first1=felicia |last2=Andreoli |first2=Claire |last3=Cofield |first3=Calia |title=NASA Missions Spy First Possible Planet Hugging a Stellar Cinder |url=https://www.jpl.nasa.gov/news/news.php?feature=7746 |date=16 September 2020 |work=[[Organization:NASA|NASA]] |access-date=17 September 2020 }}</ref><ref name="BG-20200917">{{cite web |last=Gary |first=Bruce L. |title=WD 1856+534 Transit Light Curve Photometry |url=http://www.brucegary.net/wd1856/ |date=17 September 2020 |work=BruceGary.net |access-date=17 September 2020 }}</ref> This WD 1856 system is similar to the WD 1145+017 system.

== See also ==
* [[Astronomy:Disrupted planet|Disrupted planet]]
* [[Astronomy:List of stars that dim oddly|List of stars that dim oddly]]
* [[Astronomy:ZTF J0139+5245|ZTF J0139+5245]]

== References ==
{{reflist|colwidth=30em}}

== External links ==
* [http://archive.stsci.edu/k2/epic/search.php EPIC Catalog at MAST]
* Harvard ''Center for Astrophysics'', [https://www.cfa.harvard.edu/~avanderb/k2c1/ep201563164.html  EPIC 201563164]
* AstronomyNow<!-- British magazine -->, [https://astronomynow.com/tag/wd-1145017/ WD 1145+017]
* AmericaSpace, [http://www.americaspace.com/?tag=wd-1145017 WD 1145+017]
{{Virgo}}

{{DEFAULTSORT:WD 1145+017}}
[[Category:White dwarfs]]
[[Category:Virgo (constellation)]]
[[Category:Hypothetical planetary systems]]

{{Sourceattribution|WD 1145+017}}