HE 0437-5439: Difference between revisions

| image = [[Image:HE_0437HE 0437-5439_HST5439 HST.jpg|250px]]

| appmag_v=16.342

| class=BV or sdB+F

'''HE 0437-5439''' is a massive, unbound [[hypervelocity star]] (HVS), also called '''HVS3'''.<ref name=Brown/> It is a [[main sequence]] [[Stellar classification|B-type]] [[star]] located in the [[Dorado constellation]]. It was discovered in [[2005 in astronomy|2005]] with the Kueyen {{convert|8.2|m|inch|adj=on}} telescope, which is part of the [[European Southern Observatory]]'s [[Very Large Telescope]] array. HE 0437-5439 is a young star, with an age of around 30 million years.<ref name = "ESO051109"/> The mass of the star is almost nine times greater than the mass of the [[Sun]]<ref name="Sciencedaily"/> and the star is located 200,000 light years away in the direction of the [[Dorado]] constellation, 16 degrees northwest of the [[Large Magellanic Cloud]] (LMC) and furtherfarther away than the LMC.<ref name = "ESO051109"/> The star appears to be receding at an extremely high velocity of {{Convert|723|km/s}}, or {{Convert|2600000|km/h}}. At this speed, the star is no longer [[gravity|gravitationally]] bound and will leave the [[Milky Way]] galaxy system and escape into [[intergalactic space]]. It was thought to have originated in the LMC and been ejected from it soon after birth. This could happen if it originally was one of a pair of stars and if there is a [[supermassive black hole]] in the LMC.<ref name="Sciencedaily"/>

Studies say that a triple-star system was traveling through the center of the [[Milky Way]] when it made a misstep by wanderingcame too close to the galactic[[Galactic centerCenter]] (which is thought to have a giant [[black hole]]). One of the stars was captured by the black hole and thuscausing the other two wereto pushedbe outejected offrom the [[Milky Way]], where they merged to form a hot blue star. The baby star is blazing across spacemoving at a speed of {{Convert|1600000|mi/h}}, about three times faster than ourthe [[Sun]]'s orbital velocity around the [[galaxy]]'s center., Thisand isalso enoughfaster speed to escapethan the galaxy's gravitational[[escape forcevelocity]].

The stellar outcaststar is about 200,000 [[light years]] from the centergalaxy's nowcenter. Some doubt has surrounded the previous studies based on the speed and position of HE 0437-54390437–5439. The star would have to be at least 100 million years old to have traveled that distance from the galactic core, yet its mass and blue color indicate that it had burned only for 20 million years,. whichThese observations led to the explanation that it was part of a triple-star system consisting of two closely bound stars and one outer star. The black hole pulled the outer star away, which granted the star's momentum to the tight binary system, boostingand boosted both stars to escape velocity from the galaxy. AndAs asthe theystars traveled away, they went into normal stellar evolution, with one of them becoming a red giant and engulfing the other, and forming one superstargiant -star &mdash; a blue straggler.

In 2008, a team of astronomers found a match between the star's chemical composition and the characteristics of stars in the [[Large Magellanic Cloud]]. Support that the star originated in the LMC iswas strengthened sincebecause the star is only 65,000 light- years away from the nearby galaxy.<ref>{{cite journal| doi =10.1111/j.1745-3933.2007.00280.x| title =A hypervelocity star from the Large Magellanic Cloud| date =2007| last1 =Gualandris| first1 =A.| last2 =Portegies Zwart| first2 =S.| journal =[[Monthly Notices of the Royal Astronomical Society: Letters]]| volume =376| issue =1| pages =L29–L33| doi-access =free|arxiv = astro-ph/0612673 |bibcode = 2007MNRAS.376L..29G | s2cid =2992585}}</ref><ref>{{cite journal| doi =10.1051/0004-6361:200809391| title =LMC origin of the hyper-velocity star HE 0437-5439| date =2008| last1 =Przybilla| first1 =N.| last2 =Nieva| first2 =M. F.| last3 =Heber| first3 =U.| last4 =Firnstein| first4 =M.| last5 =Butler| first5 =K.| last6 =Napiwotzki| first6 =R.| last7 =Edelmann| first7 =H.| journal =Astronomy and Astrophysics| volume =480| issue =3| pages =L37|arxiv = 0801.4456 |bibcode = 2008A&A...480L..37P | s2cid =17157851}}</ref> Later observations using the [[Hubble Space Telescope]] showed that the star originated from the Milky Way's galactic center.<ref name=Brown/>

*[[Intergalactic starsstar]]

<ref name="Sciencedaily">{{cite news|title = Hyperfast Star Proven To Be Alien|work = Space & Time|publisher = [[Science Daily]]|date = January 28, 2008|url = httphttps://www.sciencedaily.com/releases/2008/01/080128113256.htm|accessdate = January 28, 2008}}</ref>

<ref name=Brown>{{Cite journal|url=http://iopscience.iop.org/2041-8205/719/1/L23/|title=A Galactic Origin For HE 0437–5439, The Hypervelocity Star Near The Large Magellanic Cloud|first1=Warren R.|last1=Brown|first2=Jay|last2=Anderson|first3=Oleg Y.|last3=Gnedin|first4=Howard E.|last4=Bond|first5=Margaret J.|last5=Geller|first6=Scott J.|last6=Kenyon|first7=Mario|last7=Livio|journal=[[The Astrophysical Journal Letters]]|date=July 19, 2010|doi=10.1088/2041-8205/719/1/L23|volume=719|issue=1|pages=L23–L27|arxiv = 1007.3493 |bibcode = 2010ApJ...719L..23B |s2cid=55832434}}</ref>