WD 1145+017

The white dwarf has a mass of 0.6 {{solar mass}}, radius of 0.012 {{solar radius}} (1.34 {{Earth radius}}) and a temperature of 15,020 K, typical for white dwarf stars. It has been a white dwarf for 224 million years. 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.

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.

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 {{val|2.48|0.14|ul=solar mass}}, remaining so for an estimated {{val|550|100}} million years. 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 {{val|224|30}} million years. This gives the star an estimated total age of around 774 million years.

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.

{{OrbitboxPlanet begin

| name = WD 1145+017

| table_ref =

}}

{{OrbitboxPlanet

| exoplanet = b

| mass_earth = ~0.000016

| period = {{val|0.187454|(4)}}

| semimajor = ~0.0054

| radius_earth = ~0.03

| inclination = ~90

}}

{{OrbitboxPlanet disk

| disk = Dusty disk

| periapsis = 0.5?

| apoapsis =

| inclination =

}}

{{Orbitbox end}}

The supposed planetesimal, WD 1145+017 b, 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.{{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 }}{{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 }} 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.{{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 }}{{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 }}{{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 }}{{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 }}

An excess of infrared radiation indicates that there is a dusty disk with a temperature of {{convert|1150|K|C}}. Supporting observational data, along with data from the Chandra X-ray Observatory, were also found related to dust debris orbiting WD 1145+017.

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. This is the first true planet observed to transit a white dwarf, as opposed to the planetesimals transiting WD 1145+017.

• Disrupted planet
• List of stars that have unusual dimming periods
• List of exoplanets and planetary debris around white dwarfs

Other planetesimals around white dwarfs:

• ZTF J0139+5245
• WD 0145+234
• SDSS J1228+1040 b
• ZTF J0328-1219

{{reflist|colwidth=30em|refs=

{{cite simbad |title= WD 1145+017 |access-date= 25 October 2015 }}

{{Cite Gaia DR3|3796414192429498880}}

{{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 }}

{{cite encyclopedia |url= https://exoplanet.eu/catalog/wd_1145_017_b--2456/ |encyclopedia= Extrasolar Planets Encyclopaedia |title= Planet WD 1145+017 b |access-date= 30 October 2015 }}

{{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 }}

{{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}}

{{cite journal |last1=Rappaport |first1=S. |last2=Gary |first2=B. L. |date=June 2016 |title=Drifting asteroid fragments around WD 1145+017 |journal=Monthly Notices of the Royal Astronomical Society |volume=458 |issue=4 |pages=3904–3917 |doi=10.1093/mnras/stw612 |doi-access=free |arxiv=1602.00740 |bibcode=2016MNRAS.458.3904R}}

{{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 }}

{{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 |doi-access=free |bibcode=2018MNRAS.474..933R }}

{{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 |doi-access=free }}

{{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 }}

{{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 }}

{{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 }}

{{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=NASA |access-date=17 September 2020 }}

{{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 }}

}}

• [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, [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