{{short description|Nova that occurred in 2016}} {{Starbox begin}} {{Starbox image | image= {{Location mark |image=V407LupLocation.png|alt=|width=280 }} |caption=Location of V407 Lupi (circled in red) }} {{Starbox observe | epoch = [[J2000.0]] | equinox = [[J2000.0]] ([[International Celestial Reference System|ICRS]]) | constell = [[Lupus (constellation)|Lupus]] | ra = {{RA|15|29|01.820}}<ref name="stan"/> | dec = {{DEC|−44|49|40.89}}<ref name="stan"/> | appmag_v = 5.6 – 14.8 <ref name="aav2"/> }} {{Starbox character | class = | b-v = | u-b = | variable = [[Nova]]<ref name="ate2"/> }} {{Starbox catalog | names = Nova&nbsp;Lupi&nbsp;2016, V407&nbsp;Lup, PNV&nbsp;J15290182-4449409, [[All Sky Automated Survey for SuperNovae|ASASSN]]&nbsp;-16kt<ref name=SIMBAD/> }} {{Starbox reference | Simbad=V407+Lup }} {{Starbox end}}

[[File:V407LupLightCurve.png|thumb|left|The [[light curve]] of V407 Lupi, plotted from [[AAVSO]] data]] '''V407 Lupi''', also known as '''Nova Lupi 2016''', was a bright [[nova]] in the constellation [[Lupus (constellation)| Lupus]] discovered by [[All Sky Automated Survey for SuperNovae]] (ASAS-SN) on 24 September 2016. At the time of its discovery, it had an [[apparent visual magnitude]] of 9.1. The ASAS-SN team reported that no object at the nova's location brighter than magnitude 17.5 was seen on images taken four days earlier.<ref name="atel"/> Wildly incorrect coordinates (in error by many degrees) were published in the announcement telegram,<ref name="atel"/> but corrected in a subsequent telegram.<ref name="stan"/> It reached a peak brightness of magnitude 5.6, faintly visible to the naked eye, on 25 September 2016.<ref name="aav1"/><ref name="aydi"/>

V407 Lupi declined from its peak brightness very quickly, fading by 2 magnitudes in less than three days. That is one of the most rapid declines in brightness ever seen in a nova. It is therefore classified as a "very fast" nova in the classification scheme of [[Cecilia Payne-Gaposchkin]].<ref name="aydi"/><ref name="payn"/>

All novae are binary stars, with a "donor" star orbiting a [[white dwarf]]. The two stars are so close to each other that matter is transferred from the donor to the white dwarf. Observations by the satellite [[TESS]] detected a variation in the light curve of V407 Lupi indicating an orbital period for the binary system of 3.513 days;<ref name=Schaefer/> it was previously thought to be 3.573 hours,<ref name=bear/> but this has since been disproven.<ref name= Schaefer/> A second periodicity in the light curve was also detected by the [[Chandra X-ray Observatory]]<ref name=aydi/> and has a period of {{convert|591.27465|s|min}}, which appears to be the rotation period of the white dwarf.<ref name=Schaefer/><ref name="bea2"/> The very rapid decline from peak brightness indicates that the mass of the white dwarf is ≥ 1.25 {{solar mass|link=y}}, not far below the [[Chandrasekhar limit]] for white dwarf masses. The system is probably an [[intermediate polar]] nova.<ref name="aydi"/>

==See also== [[List of novae in the Milky Way galaxy]]

==References== <references>

<ref name=SIMBAD>{{cite simbad | title=V4407 Lup | access-date=2021-01-09 }}</ref>

<ref name="aav1">{{cite web|url=https://www.aavso.org/vsx/index.php?view=detail.top&oid=474105|title=VSX : Detail for ASASSN-16kt|first=Christopher|last=Watson|publisher=}}</ref>

<ref name="atel">{{cite journal |last1=Stanek |first1=K.Z. |last2=Kochanek |first2=C.S. |last3=Brown |first3=J.S. |last4=Holoien |first4=T.W.S. |last5=Shields |first5=J. |last6=Shappee |first6=B.J. |last7=Prieto |first7=J.L. |last8=Bersier |first8=D. |last9=Dong |first9=Subo |last10=Bose |first10=S. |last11=Chen |first11=Ping |last12=Chomiuk |first12=L.|author12-link=Laura Chomiuk |last13=Strader |first13=J. |last14=Brimacombe |first14=J. |title=ASAS-SN Discovery of A Likely Galactic Nova ASASSN-16kt at V=9.1 |journal=The Astronomer's Telegram |date=September 2016 |volume=9538 |page=1 |bibcode=2016ATel.9538....1S }}</ref>

<ref name="ate2">{{cite journal |last1=Izzo |first1=L. |last2=Cano |first2=Z. |last3=de Ugarte Postigo |first3=A. |last4=Thoene |first4=C. |last5=Vanzi |first5=L. |last6=Zapata |first6=A. |last7=Espinoza |first7=N. |last8=Fernandez |first8=D. |last9=Prieto |first9=J.L. |last10=Bonifacio |first10=P. |last11=Della Valle |first11=M. |last12=Molaro |first12=P. |title=Spectroscopic observations of Nova Lup 2016 |journal=The Astronomer's Telegram |date=October 2016 |volume=9587 |page=1 |bibcode=2016ATel.9587....1I }}</ref>

<ref name="aav2">{{cite web |title=Download Data |url=https://www.aavso.org/data-download |website=aavso.org |publisher=AAVSO |access-date=9 January 2021}}</ref>

<ref name="stan">{{cite journal |last1=Stanek |first1=K.Z. |last2=Team |first2=ASAS-SN |title=Erratum to ATel 9538: ASAS-SN Discovery of A Likely Galactic Nova ASASSN-16kt at V=9.1 |journal=The Astronomer's Telegram |date=September 2016 |volume=9539 |page=1 |bibcode=2016ATel.9539....1S }}</ref>

<ref name="bear">{{cite journal |last1=Beardmore |first1=A.P. |last2=Page |first2=K.L. |last3=Osborne |first3=J.P. |last4=Orio |first4=M. |title=Swift observations of nova V407 Lup: detection of a UV period at 1.1 or 3.6 hours |journal=The Astronomer's Telegram |date=11 August 2021 |volume=10632 |url=http://www.astronomerstelegram.org/?read=10632 |access-date=11 January 2021}}</ref>

<ref name="bea2">{{cite journal |last1=Beardmore |first1=Andy |last2=Dobrotka |first2=Andrej |last3=Ness |first3=Jan-Uwe |last4=Orio |first4=Marina |last5=Osborne |first5=Julian |last6=Page |first6=Kim |title=Detection of a 9.4 min periodicity in the XMM-Newton and Chandra X-ray light curves of V407 Lup (Nova Lup 2016) |journal=The Astronomer's Telegram |date=September 2017 |volume=10749 |page=1 |bibcode=2017ATel10749....1B |url=https://ui.adsabs.harvard.edu/abs/2017ATel10749....1B |access-date=11 January 2021}}</ref>

<ref name="aydi">{{cite journal |last1=Aydi |first1=E. |last2=Orio |first2=M. |last3=Beardmore |first3=A.P. |last4=Ness |first4=J.U. |last5=Page |first5=K.L. |last6=Kuin |first6=N.P.M. |last7=Walter |first7=F.M. |last8=Buckley |first8=D.A.H. |last9=Mohamed |first9=S. |last10=Whitelock |first10=P. |last11=Osborne |first11=J.P. |last12=Strader |first12=J. |last13=Chomiuk |first13=L.|author13-link=Laura Chomiuk |last14=Darnley |first14=M.J. |last15=Dobrotka |first15=A. |last16=Kniazev |first16=A. |last17=Miszalski |first17=B. |last18=Myers |first18=G. |last19=Ospina |first19=N. |last20=Henze |first20=M. |last21=Starrfield |first21=S. |author21-link=Sumner Starrfield |last22=Woodward |first22=C.E. |title=Multiwavelength observations of V407 Lupi (ASASSN-16kt) - a very fast nova erupting in an intermediate polar |journal=Monthly Notices of the Royal Astronomical Society |date=October 2018 |volume=480 |issue=1 |pages=572–609 |doi=10.1093/mnras/sty1759 |doi-access=free |arxiv=1807.00706 |bibcode=2018MNRAS.480..572A }}</ref>

<ref name="payn">{{cite book |last1=Payne-Gaposchkin |first1=Cecilia |title=The galactic novae |date=1964 |publisher=Dover |location=New York |bibcode=1964gano.book.....P }}</ref>

<ref name=Schaefer>{{cite journal |doi=10.3847/2515-5172/ac0d5b|arxiv=2106.13907|bibcode=2021RNAAS...5..150S|title=Discovery of 13 New Orbital Periods for Classical Novae|year=2021|last1=Schaefer|first1=Bradley E.|journal=Research Notes of the AAS|volume=5|issue=6|page=150|s2cid=235632263 |doi-access=free }}</ref>

</references>

{{Stars of Lupus}}

[[Category:Novae]] [[Category:Lupus (constellation)]] [[Category:Astronomical objects discovered in 2016|20160924]] [[Category:Objects with variable star designations|Lupi, V407]] [[Category:Objects with ASASSN designations]]