Editing Lyra (section)

===Deep-sky objects===
[[File:Messier 56 HST.jpg|right|thumb|[[Messier 56]] is composed of a large number of stars, tightly bound to each other by gravity.<ref>{{cite news|title=A Collection of Ancient Stars|url=http://www.spacetelescope.org/images/potw1234a/|access-date=20 August 2012|newspaper=ESA/Hubble Picture of the Week}}</ref> In Lyra are the objects M56, M57, and Kuiper&nbsp;90. [[Messier 56|M56]] is a rather loose [[globular cluster]] at a distance of approximately 32,900 [[light-year]]s, with a diameter of about 85 light-years. Its apparent brightness is 8.3m.]]
[[Ring Nebula|M57]], also known as the "Ring Nebula" and NGC 6720,<ref>{{cite book|first=David H.|last=Levy|title=Deep Sky Objects|date=2005|publisher=Prometheus Books|isbn=1-59102-361-0|url-access=registration|url=https://archive.org/details/deepskyobjects00davi|page=123}}</ref> at a distance of 2,550 light-years from Earth is one of the best known [[planetary nebula]]e and the second to be discovered; its integrated magnitude is 8.8.<ref name="objects"/> It was discovered in 1779 by [[Antoine Darquier]], 15 years after [[Charles Messier]] discovered the [[Dumbbell Nebula]].{{sfn|Levy|2005|p=125}} Astronomers have determined that it is between 6,000 and 8,000 years old;<ref name="objects"/> it is approximately one light-year in diameter.{{sfn|Levy|2005|p=124}} The outer part of the nebula appears red in photographs because of emission from [[ionized hydrogen]]. The middle region is colored green; [[doubly ionized oxygen]] emits greenish-blue light. The hottest region, closest to the central star, appears blue because of emission from [[helium]]. The central star itself is a [[white dwarf]] with a temperature of 120,000 [[kelvin]]s. In telescopes, the nebula appears as a visible ring with a green tinge; it is slightly elliptical because its three-dimensional shape is a [[torus]] or [[cylinder (geometry)|cylinder]] seen from a slight angle.<ref name="objects">{{cite book |title=300 Astronomical Objects: A Visual Reference to the Universe |first1=Jamie |last1=Wilkins |first2=Robert |last2=Dunn |publisher=Firefly Books |date=2006 |location=Buffalo, New York |isbn=978-1-55407-175-3}}</ref> It can be found halfway between [[Gamma Lyrae]] and Beta Lyrae.{{sfn|Levy|2005|p=124}}

Another planetary nebula in Lyra is [[Abell 46]]. The central star, [[V477 Lyrae]], is an eclipsing [[Post common envelope binary|post-common-envelope binary]], consisting of a white dwarf primary and an oversized secondary component due to recent accretion. The nebula itself is of relatively low surface brightness compared to the central star,<ref name="PollaccoBell1994">{{cite journal |last1=Pollacco |first1=D. L. |last2=Bell |first2=S. A. |title=A preliminary analysis of the planetary nebula central star V477 Lyrae |journal=Monthly Notices of the Royal Astronomical Society |volume=267 |issue=2 |pages=452–464 |date=1994 |bibcode=1994MNRAS.267..452P |doi=10.1093/mnras/267.2.452|doi-access=free }}</ref> and is undersized for the primary's mass for reasons not yet fully understood.<ref name="CorradiGarcía-Rojas2015">{{cite journal |last1=Corradi |first1=Romano L. M. |last2=García-Rojas |first2=Jorge |last3=Jones |first3=David |last4=Rodríguez-Gil |first4=Pablo |title=Binarity and the Abundance Discrepancy Problem in Planetary Nebulae |journal=The Astrophysical Journal |volume=803 |issue=2 |date=2015 |pages=99 |bibcode=2015ApJ...803...99C |doi=10.1088/0004-637X/803/2/99 |arxiv=1502.05182 |s2cid=118565181 }}</ref>

NGC 6791 is a cluster of stars in Lyra. It contains three age groups of stars: 4 billion year-old white dwarfs, 6 billion year-old white dwarfs and 8 billion year-old normal stars.<ref>{{Cite web|url=https://www.nasa.gov/mission_pages/hubble/science/stellar_ages.html|title=NASA - What's My Age? Mystery Star Cluster Has 3 Different Birthdays|website=www.nasa.gov|language=en|access-date=2017-02-13|archive-date=2017-06-09|archive-url=https://web.archive.org/web/20170609104517/https://www.nasa.gov/mission_pages/hubble/science/stellar_ages.html|url-status=dead}}</ref>

[[NGC 6745]] is an irregular [[spiral galaxy]] in Lyra that is at a distance of 208 million light-years. Several million years ago, it [[galaxy merger|collided]] with a smaller galaxy, which created a region filled with young, hot, blue stars. Astronomers do not know if the collision was simply a glancing blow or a prelude to a full-on merger, which would end with the two galaxies incorporated into one larger, probably [[elliptical galaxy]].<ref name="objects"/>

A remarkable long-duration [[gamma-ray burst]] was [[GRB 050525A]], which flared in 2005. The [[afterglow (gamma ray burst)|afterglow]] re-brightened at 33 minutes after the original burst, only the third found to exhibit such an effect in the timeframe,<ref name="KlotzBoër2005">{{cite journal |last1=Klotz |first1=A. |last2=Boër |first2=M. |last3=Atteia |first3=J. L. |last4=Stratta |first4=G. |last5=Behrend |first5=R. |last6=Malacrino |first6=F. |last7=Damerdji |first7=Y. |title=Early re-brightening of the afterglow of GRB 050525a |journal=Astronomy and Astrophysics |volume=439 |issue=3 |date=2005 |pages=L35–L38 |bibcode=2005A&A...439L..35K |doi=10.1051/0004-6361:200500153 |arxiv=astro-ph/0506259 |s2cid=18532205 }}</ref> and unable to be completely explained by known phenomena.<ref name="ResmiMisra2012">{{cite journal |last1=Resmi |first1=L. |last2=Misra |first2=K. |last3=Jóhannesson |first3=G. |last4=Castro-Tirado |first4=A. J. |last5=Gorosabel |first5=J. |last6=Jelínek |first6=M. |last7=Bhattacharya |first7=D. |last8=Kubánek |first8=P. |last9=Anupama |first9=G. C. |last10=Sota |first10=A. |last11=Sahu |first11=D. K. |last12=de Ugarte Postigo |first12=A. |last13=Pandey |first13=S. B. |last14=Sánchez-Ramírez |first14=R. |last15=Bremer |first15=M. |last16=Sagar |first16=R. |title=Comprehensive multiwavelength modelling of the afterglow of GRB 050525A |journal=Monthly Notices of the Royal Astronomical Society |volume=427 |issue=1 |date=2012 |pages=288–297 |bibcode=2012MNRAS.427..288R |doi=10.1111/j.1365-2966.2012.21713.x |doi-access=free |arxiv=1207.3003 |s2cid=117826705 }}</ref> The light curve observed over the next 100&nbsp;days was consistent with that of a [[supernova]] or even a [[hypernova]], dubbed [[SN 2005nc]].<ref name="Della ValleMalesani2006">{{cite journal |last1=Della Valle |first1=M. |last2=Malesani |first2=D. |last3=Bloom |first3=J. S. |last4=Benetti |first4=S. |last5=Chincarini |first5=G. |last6=D'Avanzo |first6=P. |last7=Foley |first7=R. J. |last8=Covino |first8=S. |last9=Melandri |first9=A. |last10=Piranomonte |first10=S. |last11=Tagliaferri |first11=G. |last12=Stella |first12=L. |last13=Gilmozzi |first13=R. |last14=Antonelli |first14=L. A. |last15=Campana |first15=S. |last16=Chen |first16=H.-W. |last17=Filliatre |first17=P. |last18=Fiore |first18=F. |last19=Fugazza |first19=D. |last20=Gehrels |first20=N. |last21=Hurley |first21=K. |last22=Mirabel |first22=I. F. |last23=Pellizza |first23=L. J. |last24=Piro |first24=L. |last25=Prochaska |first25=J. X. |title=Hypernova Signatures in the Late Rebrightening of GRB 050525A |journal=The Astrophysical Journal |volume=642 |issue=2 |date=2006 |pages=L103–L106 |bibcode=2006ApJ...642L.103D |doi=10.1086/504636 |arxiv=astro-ph/0604109 |s2cid=15900738 }}</ref> The host galaxy proved elusive to find at first,<ref name="ZinnGrunden2011">{{cite journal |last1=Zinn |first1=P.-C. |last2=Grunden |first2=P. |last3=Bomans |first3=D. J. |title=Supernovae without host galaxies? |journal=Astronomy & Astrophysics |volume=536 |date=2011 |pages=A103 |bibcode=2011A&A...536A.103Z |doi=10.1051/0004-6361/201117631 |arxiv=1109.4717 |s2cid=119212572 }}</ref> although it was subsequently identified.<ref name="HengLazzati2008">{{cite journal |last1=Heng |first1=Kevin |last2=Lazzati |first2=Davide |last3=Perna |first3=Rosalba|author3-link=Rosalba Perna |last4=Garnavich |first4=Peter |last5=Noriega-Crespo |first5=Alberto |last6=Bersier |first6=David |last7=Matheson |first7=Thomas |last8=Pahre |first8=Michael |title=A Direct Measurement of the Dust Extinction Curve in an Intermediate-Redshift Galaxy |journal=The Astrophysical Journal |volume=681 |issue=2 |date=2008 |pages=1116–1122 |bibcode=2008ApJ...681.1116H |doi=10.1086/588279 |arxiv=0803.2879 |s2cid=1953694 }}</ref>