DQ Herculis

{{Short description|Nova in the constellation Hercules}} {{about|the star DQ Herculis|the type of cataclysmic variable known as DQ Herculis variables|intermediate polar}} {{Starbox begin}} {{Starbox image |image=File:DQHerNebula.png |caption=RGB composite color image of the shell surrounding the nova DQ Her, made from three narrow band images: Blue = 4800Å, green = Hα at 6563 Å and red = [NII] at 6583 Å. From Santamaria ''et al.'' 2020<ref name="sant"/> }} {{Starbox observe | epoch=J2000 | ra = {{RA|18|07|30.25108}}<ref name=GaiaDR2/> | dec = {{Dec|+45|51|32.5646}}<ref name=GaiaDR2/> | appmag_v = 1.5<ref name=Wright1935/> - 15.16<ref name=Norton2007/> | constell = Hercules }} {{Starbox character | class = DBe + M2V | b-v = | u-b = | variable = DQ Her<ref name=DaiQian2009/> }} {{Starbox astrometry | radial_v = | prop_mo_ra = −0.948<ref name=GaiaDR2/> | prop_mo_dec = +12.423<ref name=GaiaDR2/> | parallax = 1.9975 | p_error = 0.0237 | parallax_footnote = <ref name=GaiaDR2/> | absmag_v = −6.94<ref name="Harrison2013"/> }} {{Starbox orbit | reference = | period_unitless = 0.1936208977 ± 0.0000000017 d<ref name=Schaefer2020/> | axis =  | axis_unitless = 0.003 AU | eccentricity =  | inclination = {{val|86.5|1.6}}<ref name=Saito2010/> | node =  | periastron =  | periarg =  | periarg_primary =  | k1 =  | k2 =  }} {{Starbox detail | component1 = A | mass = 0.6<ref name=Zhang1995/> | radius = 0.0121<ref name=Saito2010/> | luminosity = | temperature = | component2 = B | mass2 = 0.4<ref name=Zhang1995/> | radius2 = | luminosity2 = | temperature2 = }} {{Starbox catalog | names = {{odlist | name=Nova Her 1934 | V=DQ Her | 2MASS=J18073024+4551325 }}, CDS 959, PLX 4164, AN 452.1934, GCRV 10587, CSI+45-18061, SBC7 665, AAVSO 1804+45<ref name=SIMBAD/> }} {{Starbox reference | Simbad = DQ+Her }} {{Starbox end}}

[[File:DQHerLightCurve.png|thumb|left|The light curve of DQ Herculis, from AAVSO data. The pronounced "dust dip" roughly four months after peak brightness was caused by dust forming as the ejected shell expanded and cooled.<ref>{{cite journal |last1=Rosenbush |first1=A.E. |title=On the possibility of systematizing classical novae by light curve type. I. Type criteria |journal=Astrophysics |date=January 1999 |volume=42 |issue=1 |pages=43–53 |doi=10.1007/BF02700913 |bibcode=1999Ap.....42...43R |s2cid=120593343 |url=https://ui.adsabs.harvard.edu/abs/1999Ap.....42...43R |access-date=6 December 2020}}</ref>]] '''DQ Herculis''', or '''Nova Herculis 1934''', was a slow, bright nova occurring in the northern constellation of Hercules in December 1934. This cataclysmic variable star was discovered on 13 December 1934 by J. P. M. Prentice from Stowmarket, Suffolk.<ref name=britastro/> It reached peak brightness on 22 December 1934 with an apparent magnitude of 1.5.<ref name=Wright1935/> The nova remained visible to the naked eye for several months.<ref name=crimson1935/>

This is a binary star system consisting of a white dwarf primary with an estimated 60% of the mass of the Sun and a red dwarf secondary with 40% of the Sun's mass.<ref name=Saito2010/> They orbit each other tightly with a period of {{convert|0.1936208977|days|hours|2|disp=out|abbr=off}}.<ref name=Schaefer2020/> The system shows orbital period variation, possibly due to the presence of a third body.<ref name=DaiQian2009/> The orbital plane of the pair is inclined by an angle of 86.5° to the line of sight from the Earth, causing the white dwarf to undergo a deep eclipse every orbit.<ref name=Saito2010/>

DQ Herculis is the prototype for a category of cataclysmic variable stars called intermediate polars.<ref name=DaiQian2009/> The red dwarf has filled its Roche lobe and matter is being drawn off at the rate of {{nowrap|2.7 × 10<sup>−9</sup> {{solar mass}} yr<sup>−1</sup>}}, forming an accretion disk orbiting the primary. This disk has inferred temperatures ranging from 5,000 to {{val|13500|u=K|fmt=commas}}. A bright spot in the inner disk appears to pulsate with a 71-second period. In this class of variables, the white dwarf is magnetized, directing infalling matter onto the magnetic poles.<ref name=Saito2010/>

[[File:DQHerNebulaExpanding.png|thumb|left|Two images of the shell surrounding DQ Hercules taken 21 years apart, showing the nebula's expansion. Both were taken with Hα filters, left at the William Herschel Telescope, and right with the Nordic Optical Telescope.<ref name="sant"/>]] The shell of ejected material from the nova outburst is visible as an emission nebula, similar in appearance to a planetary nebula. This roughly elliptical nebula had a size of 32.0 × 24.2 arc seconds as of 2018, and it is expanding at a rate of about 0.16 arc seconds per year.<ref name="sant">{{cite journal |last1=Santamaria |first1=E. |last2=Guerrero |first2=M.A. |last3=Ramos-Larios |first3=G. |last4=Toala |first4=J.A. |last5=Sabin |first5=L. |last6=Rubio |first6=G. |last7=Quino-Mendoza |first7=J.A. |title=Angular Expansion of Nova Shells |journal=The Astrophysical Journal |date=March 2020 |volume=892 |issue=1 |page=60 |doi=10.3847/1538-4357/ab76c5 |arxiv=2002.06749 |bibcode=2020ApJ...892...60S |s2cid=211132830 |doi-access=free }}</ref>

==In popular culture== thumb|left|The location of nova DQ Herculis (circled in red) The nova was one of the brightest objects observable in the night sky. In addition to scientific articles, and received significant coverage in popular news publications.<ref name=Kaempffert1934/><ref name=Time1934/> Brad Ricca, an English professor at Case Western Reserve University, has suggested that Nova Herculis may have influenced the development of the origin story of the comic book superhero Superman.<ref name=space2013/>

{{clear left}} == References == <references> <ref name=SIMBAD>{{cite simbad | title=DQ Her | access-date=2020-11-14 | postscript=. }}</ref>

<ref name=Norton2007>{{cite journal | display-authors=1 | last1=Norton | first1=A. J. | last2=Wheatley | first2=P. J. | last3=West | first3=R. G. | last4=Haswell | first4=C. A. | last5=Street | first5=R. A. | last6=Collier Cameron | first6=A. | last7=Christian | first7=D. J. | last8=Clarkson | first8=W. I. | last9=Enoch | first9=B. | last10=Gallaway | first10=M.| last11=Hellier | first11=C. | last12=Horne| first12=K. | last13=Irwin | first13=J. | last14=Kane | first14=S. R. | last15=Lister| first15=T. A. | last16=Nicholas | first16=J. P. | last17=Parley | first17=N. | last18=Pollacco | first18=D. | last19=Ryans | first19=R. | last20=Skillen | first20=I. | last21=Wilson | first21=D. M. | title=New periodic variable stars coincident with ROSAT sources discovered using SuperWASP | journal=Astronomy and Astrophysics | volume=467 | issue=2 | pages=785–905 | year=2007 | bibcode=2007A&A...467..785N | s2cid=16358048 | arxiv=astro-ph/0702631 | doi=10.1051/0004-6361:20077084 }}</ref>

<ref name=Saito2010>{{cite journal | title=Spectral Mapping of the Intermediate Polar DQ Herculis | last1=Saito | first1=R. K. | last2=Baptista | first2=R. | last3=Horne | first3=K. | last4=Martell | first4=P. | display-authors=1 | journal=The Astronomical Journal | volume=139 | issue=6 | pages=2542–2556 | date=June 2010 | arxiv=1005.1612 | bibcode=2010AJ....139.2542S | doi=10.1088/0004-6256/139/6/2542 | s2cid=118447217 }}</ref>

<ref name=Zhang1995>{{cite journal | title=The 71 Second Oscillation in the Light Curve of the Old Nova DQ Herculis | last1=Zhang | first1=E. | last2=Robinson | first2=E. L. | last3=Stiening | first3=R. F. | last4=Horne | first4=Keith | display-authors=1 | journal=Astrophysical Journal | volume=454 | page=447 | date=November 1995 | bibcode=1995ApJ...454..447Z | doi=10.1086/176496 }}</ref>

<ref name=Schaefer2020>{{cite journal | title=Sudden and steady orbital period changes across the classical nova eruptions of DQ Her and BT Mon | last=Schaefer | first=Bradley E. | journal=Monthly Notices of the Royal Astronomical Society | volume=492 | issue=3 | pages=3323–3342 | date=March 2020 | arxiv=1912.06169 | bibcode=2020MNRAS.492.3323S | doi=10.1093/mnras/stz3325 | doi-access=free | s2cid=209370404 }}</ref>

<ref name="Harrison2013">{{cite journal | title=Hubble Space Telescope Fine Guidance Sensor Parallaxes for Four Classical Novae | last1=Harrison | first1=Thomas E. | last2=Bornak | first2=Jillian | last3=McArthur | first3=Barbara E. | last4=Benedict | first4=G. Fritz | display-authors=1 | journal=The Astrophysical Journal | volume=767 | issue=1 | at=7 | date=2013 | arxiv=1302.3245 | bibcode=2013ApJ...767....7H | doi=10.1088/0004-637X/767/1/7 | s2cid=118376206 }}</ref>

<ref name=britastro>{{Cite web | title=DQ Her | website=www.britastro.org | url=http://www.britastro.org/vss/00191a.html | access-date=2017-08-09 }}</ref>

<ref name=Wright1935>{{cite journal | title=Comments on Nova Herculis 1934 | last=Wright | first=W. H. | journal=Publications of the Astronomical Society of the Pacific | volume=47 | number=275 | pages=47–49 | year=1935 | jstor=40670634 | bibcode=1935PASP...47...47. | doi=10.1086/124534 }}</ref>

<ref name=DaiQian2009>{{cite journal | last1=Dai | first1=Z. B. | last2=Qian | first2=S. B. | title=Plausible explanations for the variations of orbital period in the old nova DQ Herculis | journal=Astronomy and Astrophysics | volume=503 | issue=3 | pages=883–888 | year=2009 | doi=10.1051/0004-6361/200810909 | doi-access=free | bibcode=2009A&A...503..883D }}</ref>

<ref name=Kaempffert1934>{{cite news | title=The Week In Science: STAR OF BETHLEHEM A NOVA?; Recent Brilliant Outburst Recalls the Orb the Magi Followed | first=Waldemar | last=Kaempffert | date=1934-12-23 | work=The New York Times | url=https://select.nytimes.com/gst/abstract.html?res=9E02E6D6103EE53ABC4B51DFB467838F629EDE&n=Top%2fClassifieds%2fReal%20Estate%2fColumns%2fLiving%20In | access-date=2013-08-08 }}</ref>

<ref name=Time1934>{{cite magazine | title=Science: Nova Herculis; Swaseya | date=1934-12-31 | magazine=Time | access-date=2013-08-08 | url=http://www.time.com/time/magazine/article/0,9171,754501,00.html | archive-url=https://web.archive.org/web/20101125080829/http://www.time.com/time/magazine/article/0,9171,754501,00.html | url-status=dead | archive-date=November 25, 2010 }}</ref>

<ref name=space2013>{{cite web|url=http://www.space.com/21949-superman-origin-star-explosion.html|title=Superman's Origins Possibly Born from Star Explosion|website=Space.com |date=2013-07-12|access-date=2013-08-07}}</ref>

<ref name=crimson1935>{{cite web|url=http://www.thecrimson.com/article/1935/12/7/nova-herculis-discovered-in-december-1934/|title=Nova Herculis, Discovered in December 1934, Varies From First to Thirteenth Magnitudes--Now Fading, About Sixth|date=1935-12-07|access-date=2013-08-08}}</ref> </references>

==External links== * http://www.daviddarling.info/encyclopedia/N/Nova_Herculis_1934.html

Category:Novae Category:Nova remnants Category:M-type main-sequence stars Category:Intermediate polars Category:Hypothetical planetary systems Category:Hercules (constellation) Category:1934 in science Herculis, DQ 19341213