Planets with short orbital periods (roughly under 10 days) are common around stars like the Sun1,2. Stars expand as they evolve and thus we expect their close planetary companions to be engulfed, possibly powering luminous mass ejections from the host star3–5. However, this phase has never been directly observed. Here we report observations of ZTF SLRN-2020, a short-lived optical outburst in the Galactic disk accompanied by bright and long-lived infrared emission. The resulting light curve and spectra share striking similarities with those of red novae6,7—a class of eruptions now confirmed8 to arise from mergers of binary stars. Its exceptionally low optical luminosity (approximately 1035 erg s−1) and radiated energy (approximately 6.5 × 1041 erg) point to the engulfment of a planet of fewer than roughly ten Jupiter masses by its Sun-like host star. We estimate the Galactic rate of such subluminous red novae to be roughly between 0.1 and several per year. Future Galactic plane surveys should routinely identify these, showing the demographics of planetary engulfment and the ultimate fate of planets in the inner Solar System.
Pulmonary drug delivery system M.pharm -2nd sem P'ceutics
An infrared transient from a star engulfing a planet
1. Nature | Vol 617 | 4 May 2023 | 55
Article
Aninfraredtransientfromastarengulfinga
planet
Kishalay De1✉, Morgan MacLeod2
, Viraj Karambelkar3
, Jacob E. Jencson4
,
Deepto Chakrabarty1
, Charlie Conroy2
, Richard Dekany5
, Anna-Christina Eilers1
,
Matthew J. Graham3
, Lynne A. Hillenbrand3
, Erin Kara1
, Mansi M. Kasliwal3
, S. R. Kulkarni3
,
Ryan M. Lau6
, Abraham Loeb2,7
, Frank Masci8
, Michael S. Medford9,10
, Aaron M. Meisner6
,
Nimesh Patel2
, Luis Henry Quiroga-Nuñez11
, Reed L. Riddle5
, Ben Rusholme8
, Robert Simcoe1
,
Loránt O. Sjouwerman12
, Richard Teague2,13
& Andrew Vanderburg1
Planetswithshortorbitalperiods(roughlyunder10 days)arecommonaroundstars
liketheSun1,2
.Starsexpandastheyevolveandthusweexpecttheircloseplanetary
companionstobeengulfed,possiblypoweringluminousmassejectionsfromthe
hoststar3–5
.However,thisphasehasneverbeendirectlyobserved.Herewereport
observationsofZTFSLRN-2020,ashort-livedopticaloutburstintheGalacticdisk
accompaniedbybrightandlong-livedinfraredemission.Theresultinglightcurve
andspectrasharestrikingsimilaritieswiththoseofrednovae6,7
—aclassoferuptions
nowconfirmed8
toarisefrommergersofbinarystars.Itsexceptionallylowoptical
luminosity (approximately 1035
erg s−1
) and radiated energy (approximately
6.5 × 1041
erg)pointtotheengulfmentofaplanetoffewerthanroughlytenJupiter
massesbyitsSun-likehoststar.WeestimatetheGalacticrateofsuchsubluminousred
novaetoberoughlybetween 0.1andseveralperyear.FutureGalacticplanesurveys
shouldroutinelyidentifythese,showingthedemographicsofplanetaryengulfment
andtheultimatefateofplanetsintheinnerSolarSystem.
Using data from the Zwicky Transient Facility (ZTF) time domain
survey9
, we searched for slowly evolving outbursts near the Galactic
plane (Supplementary Information 1). We identified a transient opti-
cal source, named ZTF 20aazusyv, at celestial J2000 coordinates
α = 19:09:39.783, δ = +05:35:04.269 (Supplementary Information 5;
hereafter,ZTFSLRN-2020),thatexhibitedarapidrisefromquiescence
to peak outburst flux in approximately 10 days, subsequently fading
byabouttenfoldover6 months(Fig.1andExtendedDataFigs.1and2).
The long optical outburst duration, together with its faint peak flux,
distinguishesitfromcommonGalacticplanetransientsresultingfrom
whitedwarfswithclosebinarycompanions(the‘dwarf’and‘classical’
novae10
). The transient also exhibits a mid-infrared (IR) brightening
starting at around 7 months before the optical outburst, together
with bright mid-IR emission (over 50-fold brighter than the optical
r-bandat around 4 monthsafteropticalpeak),thatlastedforroughly
atleast 15 months.NoX-rayemissionwasdetectedinfollow-upobser-
vations during the outburst using the Swift telescope11
, ruling out an
unstable disk accretion episode around a neutron star or black hole12
(Supplementary Information 4).
The bright mid-IR emission during the outburst is suggestive
of emission from a warm dust shell surrounding the stellar photo-
sphere. We model the optical to mid-IR spectral energy distribution
(SED; Supplementary Information 12) at around 120 days after the
optical peak. The analysis shows a relatively hot inner photosphere
(approximately 9,000 K)surroundedbyawarmdustshellofapproxi-
mately 1,000 K, located behind a dust visual extinction column of AV
(approximately 3.6 mag; Fig. 2, Extended Data Figs. 5 and 6 and
Extended Data Table 3). Using the 90% confidence interval on the
foregroundextinction,togetherwiththree-dimensionalGalacticdust
distributionmaps(SupplementaryInformation13andExtendedData
Fig.7),weinferthesourcetobelocatedatadistanceof2–7 kpc.Ajoint
analysis of the overlap between the different dust maps suggests a
probable distance of roughly 4 kpc. Performing the same analysis at
around 320 days after peak, we find the SED to have predominantly
shifted into the IR bands caused by an increase in dust optical depth
that can be attributed to the formation of about 10−6
M⊙ of dust (for a
distance of 4 kpc).
Using the best estimate for foreground extinction, we construct
a bolometric luminosity light curve for the outburst (Fig. 2 and Sup-
plementary Information 13). The light curve is characterized by an
initialplateauataluminosityofaround 1035
× (d/4 kpc)2
erg s−1
lasting
approximately 25days(SupplementaryInformation13)beforefading
by a factor of 5 over the next (roughly) 100 days. The effective tem-
peratureofthephotosphereremainsconstantataround (6−7) × 103
K
duringtheplateauphase,presumablyregulatedbytherecombination
temperatureofhydrogen13
,beforefadingandcoolingtoabout 5 × 103
K.
https://doi.org/10.1038/s41586-023-05842-x
Received: 29 September 2022
Accepted: 14 February 2023
Published online: 3 May 2023
Check for updates
1
Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA, USA. 2
Center for Astrophysics/Harvard & Smithsonian, Cambridge, MA, USA.
3
Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA, USA. 4
Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA. 5
Caltech Optical
Observatories, California Institute of Technology, Pasadena, CA, USA. 6
NSF’s National Optical-Infrared Astronomy Research Laboratory, Tucson, AZ, USA. 7
Black Hole Initiative, Harvard University,
Cambridge, MA, USA. 8
IPAC, California Institute of Technology, Pasadena, CA, USA. 9
Department of Astronomy, University of California, Berkeley, Berkeley, CA, USA. 10
Lawrence Berkeley
National Laboratory, Berkeley, CA, USA. 11
Department of Aerospace, Physics and Space Sciences, Florida Institute of Technology, Melbourne, FL, USA. 12
National Radio Astronomy Observatory,
Array Operations Center, Socorro, NM, USA. 13
Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA. ✉e-mail: kde1@mit.edu
2. 56 | Nature | Vol 617 | 4 May 2023
Article
Thetotalradiatedenergyisapproximately 6.5 × 1041
(d/4 kpc)2
ergover
the first (roughly) 150 days.
On UT 2020 November 20, we obtained an optical spectrum of the
transientusingtheKeck-Itelescope(ExtendedDataTable2).Thespec-
trum(Fig.3)exhibitsanalmostfeaturelessredcontinuumcontaining
onlyatomic(Na,Ba,HandMg)andmolecularabsorptionfeatures(VO
andTiO).Theabsenceofatomicemissionlinesduringtheoutburstis
inconsistentwithcommonGalacticplanetransientssuchasaccretion/
thermonuclearoutburstsindwarfandclassicalnovae10
,wherehotgas
produces emission lines due to atomic recombination and ions (Sup-
plementaryInformation11andExtendedDataFigs.3and4).Whereas
ZTF SLRN-2020 shows some similarities to outbursting young stars,
itexhibitsstrikingdifferencesinitsrapidcoolingtoaSEDdominated
by IR emission (suggestive of a cooling photosphere), complete lack
ofemissionlines(thatis,ubiquitousinhotgasaccretion)aswellasits
sky location away from known star-forming regions (Supplementary
Information 11). Instead, the molecular features are suggestive of a
cool outer photosphere consistent with an M4-III-type giant star and
effective temperature of around 3,600 K (Supplementary Informa-
tion11).Contemporaneousnear-IR(NIR)spectra(Fig.3)obtainedwith
the Palomar 200 inch telescope show only broad molecular absorp-
tion bands from H2O, and probably from TiO, VO and CO, consist-
ent with an M7-III-type giant possessing an extended, cool envelope
(SupplementaryInformation11).Late-timeNIRspectra(Fig.3)obtained
around 700 days after the optical peak with the Magellan Baade and
Keck-II telescopes show only a relatively featureless continuum with
broad H2O absorption.
The distinctively cool molecular spectroscopic features, together
withsubstantialreddeningoftheSEDduringtheoutburst,arereminis-
centoftheclassofrednovae8,14–17
.Directphotometricobservationsof
thebinaryorbitaldecaybeforetherednovaV1309Sco8
providestrong
evidence for the association of these events with catastrophic merg-
ers of binary stars. Because the primary star engulfs its companion, a
powerful outflow is launched from the binary system that gradually
cools and powers a ‘plateau’ in the light curve of the optical transient
via recombination of hydrogen6
. Subsequently, the expanding enve-
lopecoolsandformsdustleadingtotheemergenceofaphotosphere
dominated by molecular absorption and a luminous, long-lived IR
transient18,19
.
The photometric and spectroscopic properties of ZTF SLRN-2020
share striking similarities with both Galactic and extragalactic red
novae(SupplementaryInformation10andExtendedDataFigs.1and2).
Nevertheless, its remarkably low luminosity, even if placed on the
far side of the Galactic disk (no nore than around a few × 1036
erg s−1
),
makesitexceptionalamongthepopulationofrednovaethatreachthe
Eddingtonluminosityoftheprimarystars(around 1038
erg s−1
fora1 M⊙
20′′
N
E
2.0′′
–400 0 200 400
Time from i-band peak (MJD 58993; days)
10–3
10–2
10–1
100
101
Difference
in
flux
(mJy)
I O W
W
SED
outburst
SED
late
ZTF-r ZTF-g ZTF-i ATLAS-o ATLAS-c WISE-W1 WISE-W2
–40 0
10–2
10–1
UKIRT JHK composite
2007–2009
a unWISE W1+ W2
2020 October
b c WIRC JHK composite
2021 March
d Gemini-S/GSAOI J
2022 April
e
–20
–200
Fig.1|DiscoverylocationandmulticolourlightcurvesofZTFSLRN-2020.
a,AfaintprogenitoridentifiedinarchivalNIRimagesfromtheUKIRTGalactic
PlaneSurvey.b,Mid-IRtransientsourcedetectedinNEOWISEimagesfrom
2020.c,NIRcompositefollow-upimage(whitesquaremasksoutanearby
regionwithadetectorartefact)ofthetransientduring2021.Thespatialscales
inpanelsa–careidentical.d,Zoomed-in,high-spatial-resolutionimageofthe
IRremnantin2022.e,MulticolourlightcurvesoftheoutburstfromtheZTF9
,
ATLAS48
andNEOWISE49
surveys(asindicatedinthelegend).Errorbarsareshown
at1σconfidence,and5σupperlimitsareshownassymbolswithdownward
arrows.IandOindicatethetimesofNIRandopticalspectroscopyofthe
transient,respectively,withWshowingtheepochofP200NIRimaging.
VerticaldashedlinesrepresentthetimerangesusedtoperformSEDmodelling
duringtheoutburstin2020(SEDoutburst)andaftertheopticaltransienthad
fadedawayin2021(SEDlate).Insetshowsaclose-upoftheearly-timelight
curve(shadedingreyinthemainpanel),showingfainti-bandprecursor
emissionanddetectionofmid-IRemissionbeforetheonsetoftheoptical
outburst.
3. Nature | Vol 617 | 4 May 2023 | 57
star). We show ZTF SLRN-2020 in the phase space of luminosity and
timescales (Fig. 4 and Supplementary Information 13) for red novae,
togetherwithanalyticalcontoursforthemassandvelocityofejecta,in
modelsofstellarmergers7
.Theextremelylowluminosityisreasonably
explained by around only 10−5
−10−4
M⊙ of hydrogen launched in the
outflow7
. The small ejected mass is consistent with the nondetection
of radio molecular line emission in follow-up observations with the
SubmillimeterArray(SMA)andVeryLargeArray(VLA;Supplementary
Information 8 and 9).
Usingahigh-spatial-resolutionimageobtainedwiththeGemini-South
telescope about 2 years after the outburst peak, we identified a faint
progenitor source (Supplementary Information 14) in archival NIR
imagesfromtheUnitedKingdomInfraredTelescope(UKIRT)Galactic
planesurvey20
.Althoughlimitedbyphotometricerrors,itsbrightness
andcoloursareconsistentwithastarofaround 0.8−1.5 M⊙ onthemain
sequenceorearlyinthesub-giantbranch(radius,1−4 R⊙;ExtendedData
Fig. 8 and Extended Data Table 1). The IR progenitor is thus similar to
theSun,andtotheprimarystarofV1309Sco,whichwasamergerevent
involving a low-mass q = 0.1 companion, where q is the companion to
primary mass ratio8,21–24
.
We draw constraints on the mass of the merging object from both
the light curve and pre-outburst detections. ZTF SLRN-2020’s ejecta
massandradiatedenergyarebothapproximately 103
-foldlowerthan
thoseofV1309Sco(Fig.4).Linearlyscalingthecompanionmasswith
thesepropertiesimpliesagiantplanetcompanionofaround 0.1 MJ.The
presenceofpre-outburstdustandgassuggestsanongoinginteraction
(Extended Data Fig. 9) that escalates to produce the outburst22,24,25
,
rather than a direct collision. The pre-outburst dust model that best
matchesthedatahasq = 10−2
oracompanionmassofabout 10 MJ (Fig.4
and Supplementary Information 18). Therefore, all our estimates
100
Wavelength (μm)
10–13
10–12
Flux
OF
λ
(erg
cm
–2
s
–1
)
Phase +125 days AV = 3.6 mag
L = 5.0 L
W = 1.8
Td = 1,014 K
T* = 8,970 K
rin = 1.0 AU
a
100
10–13
10–12
Phase +320 days
L = 5.5 L
W = 13.0
Td = 415 K
T* = 4,300 K
rin = 3.7 AU
1034
1035
1036
L
(erg
s
−1
)
L ∝ t−4/5
V838 Mon ×10–4
V1309 Sco ×10–3
V4332 Sgr ×10–2
M31-OT 2015 ×10–4
AT2019zhd ×10–4
AT2018bwo ×10–5
2
4
6
8
T
(10
3
K)
ZTFSLRN-2020
101 102
Time since peak (days)
1011
1012
R
(cm)
V838Mon ×10–3
V1309Sco ×10–2
V4332Sgr ×10–2
M31-OT2015 ×10–2
AT2019zhd ×10–2
AT2018bwo ×10–3
c
b
Flux
OF
λ
(erg
cm
–2
s
–1
)
Wavelength (μm)
Fig.2|Temporalevolutionofthespectralenergydistributionand
integratedluminosityofZTFSLRN-2020.a,Best-fitmodel(parametersare
shown)fortheSEDofZTFSLRN-2020(shownasblackcircles)ataround 125 days
afteroutburstpeak.Blacksolidlinesdenotetotalflux,browndot-dashedlines
denotedustemissionandgreendashedandbluedottedlinesdenotescattered
andattenuatedstellaremission,respectively.b,Asinabutroughly 320 days
afteroutburstpeak.c,Bolometricluminosity(top),temperature(middle)and
radius(bottom)evolutionofZTFSLRN-2020foranestimateddistanceof4 kpc
andaforegroundinterstellarextinctionofAV = 3.6 mag.Redsquaresinthe
toppanelrepresentluminosityestimatedfromthetwoepochsofDUSTY
modelling.Forcomparison,wealsoshowtheevolutionoftheseparametersfor
previousrednovae,thebest-fitlightcurveplateaumodel(blackdottedline)and
theL ∝ t−4/5
luminositydecayexpectedforamergerremnant(blackdashedline;
SupplementaryInformation13).Theradiusandluminosityofarchivalevents
havebeenscaledasindicated.Errorbarsareshownat1σconfidence.
4. 58 | Nature | Vol 617 | 4 May 2023
Article
squarely point to a close planetary companion to the primary star,
plausibly a Neptune- or Jupiter-like planet strikingly similar to known
systems26
.
Theoveralldurationofthelightcurvesuggestsamassejectionveloc-
ity of roughly 30 km s−1
(Fig. 4), which is substantially lower than the
stellarescapevelocity.Wecanunifytheseestimateswithourtheoretical
understandingofhowplanetaryengulfmentmightaffectahoststar.In
particular, the smaller the engulfed companion the less dramatic the
disturbance to the primary star and the smaller fraction of material
thatisexpectedtobeejectedatsufficientlyhighvelocitiestobecome
unbound27–29
. The short-lived (around 25 days) plateau phase in ZTF
SLRN-2020 may be powered by the ejection and unbinding of a small
amount(lessthanabout10−4
M⊙)ofmassatvelocitiesapproachingthe
stellarescapevelocity(about100 km s−1
;Fig.4).TheradiusofZTFSLRN-
2020(Fig.2)remainsroughlyconstantatabout 3 × 1011
× (d/4 kpc) cm
duringtheplateauandrecedesduringthefadingphase,similartothat
expectedforthegravitationalcontractionofamergerremnant19
.These
features suggest that the late-time decay over the next 100 days or so
is powered by hydrodynamic and thermal readjustment of the star
following the ingestion of its planetary companion.
Our interpretation of ZTF SLRN-2020 as the engulfment event of a
planetarymassobjectbyaSun-likestarprovidesevidenceforamissing
link in our understanding of the evolution and final fates of planetary
systems.Ithaslongbeenknownthatthepopulationofplanetsinshort
orbital periods1,2,30,31
has sufficiently low orbital angular momentum
suchthattheyareunstabletotidaldissipationandareboundtomerge
withtheirhoststars32–35
.Thisisconsistentwiththelackofoldplanetary
systems with short orbital periods36,37
, as well as the dearth of close
planets around sub-giant stars38–40
. Therefore, to our knowledge, the
observationsreportedhereofferthefirstdirectinsightintotheeffectof
planetaryengulfmentontheirhoststarstointerpretcommonindirect
techniques used to infer past planetary engulfment via its effects on
long-term stellar luminosity5,41
, chemical enrichment42–44
and stellar
rotation45–47
. With empirical and theoretical rate predictions ranging
from0.1toseveralperyear(SupplementaryInformation16and20)for
similar ‘subluminous red novae’, upcoming combined optical and IR
surveys of the Galactic plane may show many similar events via their
distinctive, short-lived optical outbursts accompanied by long-lived
IR emission.
Onlinecontent
Anymethods,additionalreferences,NaturePortfolioreportingsum-
maries, source data, extended data, supplementary information,
0.4 0.5 0.6 0.7 0.8 0.9 1.0
Wavelength (μm)
Scaled
F
λ
+
constant
TiO 8859
TiO 9209
Hα
TiO 9728
Na ID
Ba II
Mg II
TiO 7589
VO 7912 VO 8624
ZTFSLRN-2020
Keck/LRIS +180 days
HV2255 M4-III
V838Mon +61 days
AT2018bwo +51 days
a
0.58 0.60 0.62 0.64 0.66
Ba II Hα
Na D
1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4
P200/TSpec
P200/TSpec
+160 days
+160 days
AT2018bwo
+103 days
HD108849
M7-III
Magellan/Keck
Magellan/Keck
+690 days
+690 days
H2O
TiO
VO
TiO
VO
12CO
b
Scaled
F
λ
+
constant
Wavelength (μm)
H2O
Fig.3|OpticalandIRspectraofZTFSLRN-2020.a,Opticalspectrumofthe
outburst(black)obtainedabout 180 daysafterpeak.Thespectrumshows
clearatomicandmolecularabsorptionfeatures,similartotheM4-III-type
giantHV 2255.Forcomparison,late-timeopticalspectraofapreviousGalactic
rednova(V838 Mon,inorange)andanextragalacticluminousrednova
(AT 2018bwo,inmagenta)areshownafterapplyingtheinferredforeground
extinction50
.Theinsetshowsaclose-upofthespectraaroundtheregionof
atomiclinesNa D,HαandBa II.b,NIRspectrumofZTFSLRN-2020(black)at
around +160 daysandaround +690 daysafteropticalpeak,showingclear
broadmolecularabsorptionfeaturesofH2O,TiO,VOandprobablyCO,similar
totheM7-IIIgiantHD 108849(showninred).Similarfeaturesarealsoseenin
NIRspectraofthepreviouslyknownextragalacticrednovaAT 2018bwo(shown
inmagenta).
5. Nature | Vol 617 | 4 May 2023 | 59
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101 102
Outburst duration (days)
1035
1036
1037
1038
1039
1040
1041
Luminosity
L
90
(erg
s
−1
)
V4332 Sgr
V838 Mon
V1309 Sco
NGC 4490-OT2011
M31-OT2015
M101-OT2015
SNHunt 248
AT 2014ej AT 2017jfs
AT 2018bwo
AT2018hso
AT 2019zhd
AT 2020kog
AT2020hat
ZTFSLRN-2020
ZTFSLRN-2020
10−5 M(
10−4 M(
10−1 MJ
10–3 M(
100 MJ
10−2 M(
101
MJ
10−1 M(
102 MJ
100 M(
103 MJ
101 M(
104 MJ
102 M(
1,000 km s−1
a
−2.0 −1.5 −1.0 −0.5 0
Time from merger (years)
10−8
10−7
10−6
Dust
mass
(M
(
)
q = 10−1
q = 10−2
q = 10−3
100 km s−1
10 km s−1
b
10–2
MJ
Fig.4|ComparisonofZTFSLRN-2020outburstwiththephasespaceof
luminosity(L90)andtimescales(t90)forpreviouslyknownrednovae.
a, Contoursshowinferredejectaphysicalparameters7
—ejectamassinunitsof
solarandJupitermassontheleft-handside,andoutflowvelocityinunitsof
km s−1
(inmagenta)ontheright-handside.SolidandhollowstarsdenoteZTF
SLRN-2020viaitslightcurveplateaudurationandtimetakentorelease90%of
thetotalradiatedenergy,respectively(SupplementaryInformation13).The
inferredejectamassofZTFSLRN-2020is100-foldlowerthananyotherknown
rednova,andthecharacteristicvelocitiesarealsonearlyanorderofmagnitude
lower.b,Comparisonofpre-outburstdustmassestimatedfromprecursor
mid-IR emission of ZTF SLRN-2020 (denoted by stars) with models of
precoalescencemasslossfora1 M⊙ starevolvingoffthemainsequencewith
binarymassratioq = 10−3
−10−1
.Solidlinescorrespondtoaninitialradiusof2 R⊙,
andtheshadedregionshowsvariationsforradiiof1−4 R⊙.Errorbarsinpanelsa
andbareshownat1σconfidence.
7. Dataavailability
All the data used in this work are provided in Extended data.
Codeavailability
K.D. will provide python code used to analyse the observations, and
any data used to generate figures, on request. The RLOF code used to
model the pre-outburst light curve is publicly available.
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Acknowledgements K.D.’s work was supported by NASA through NASA Hubble Fellowship
grant no. HST-HF2-51477.001 awarded by the Space Telescope Science Institute, which is
operated by the Association of Universities for Research in Astronomy, Inc., for NASA under
contract no. NAS5-26555. M.M.’s contributions were supported by the National Science
Foundation under grant no. 1909203. A.-C.E. acknowledges support by NASA through NASA
Hubble Fellowship grant no. HF2-51434 awarded by the Space Telescope Science Institute,
which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA
under contract no. NAS5-26555. S.R.K. thanks the Heising-Simons Foundation for supporting
his research. We thank B. Metzger, T. Matsumoto, M. Soares-Furtado and J. van Roestel for
discussions. The discovery of the optical transient was based on observations obtained with
the Samuel Oschin Telescope 48-inch and the 60-inch Telescope at the Palomar Observatory
as part of the Zwicky Transient Facility (ZTF) project. ZTF is supported by the National Science
Foundation under grant nos. AST-1440341 and AST-2034437, and by a collaboration including
Caltech, IPAC, the Weizmann Institute of Science, the Oskar Klein Center at Stockholm
University, the University of Maryland, the University of Washington, Deutsches Elektronen-
Synchrotron and Humboldt University, Los Alamos National Laboratories, the TANGO
Consortium of Taiwan, Trinity College Dublin, the University of Wisconsin at Milwaukee, IN2P3
France, Lawrence Livermore National Laboratories and Lawrence Berkeley National Laboratories.
Operations are conducted by COO, IPAC and UW. The ZTF forced-photometry service was
funded under Heising-Simons Foundation grant no. 12540303 (PI: Graham). Some of the data
presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific
partnership including the California Institute of Technology, the University of California and the
National Aeronautics and Space Administration. The Observatory was made possible by the
generous financial support of the W.M. Keck Foundation. The Submillimeter Array is a joint
project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute
of Astronomy and Astrophysics, and is funded by the Smithsonian Institution and Academia
Sinica. The authors wish to recognize and acknowledge the very significant cultural role and
reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian
community; we are most fortunate to have had the opportunity to conduct observations from
this mountain. The National Radio Astronomy Observatory is a facility of the National Science
Foundation operated under cooperative agreement by Associated Universities, Inc.
Author contributions K.D. identified the object, initiated follow-up observations, carried out
the analysis and wrote the manuscript. M.M. and A.L. led the theoretical interpretation of the
transient, created the models presented in this work and wrote the manuscript. V.K., J.E.J.,
A.-C.E., L.A.H., M.M.K. and R.M.L. assisted with optical/IR follow-up observations, data
interpretation and analysis. D.C., C.C., E.K., S.R.K., R.S. and A.V. assisted with interpretation of
the data. R.D., M.J.G., F.M., M.S.M., R.L.R. and B.R. are builders of the ZTF observing system and
contributed to survey operations during the observations presented here. A.M.M. assisted with
analysis of NEOWISE data. N.P. and R.T. assisted with acquisition of SMA data and carried out
SMA data analysis. L.H.Q.-N. and L.O.S. assisted with acquistion of VLA data and carried out
VLA data analysis. All authors contributed to scientific interpretation.
Competing interests The authors declare no competing interests.
Additional information
Supplementary information The online version contains supplementary material available at
https://doi.org/10.1038/s41586-023-05842-x.
Correspondence and requests for materials should be addressed to Kishalay De.
Peer review information Nature thanks Smadar Naoz and the other, anonymous, reviewer(s)
for their contribution to the peer review of this work.
Reprints and permissions information is available at http://www.nature.com/reprints.
17. Extended Data Table 1 | Archival photometry of the
progenitor of ZTF SLRN-2020 along with the time of
observation
Upper limits are reported at 5σ confidence.
18. Article
Extended Data Table 2 | Spectroscopic follow-up of ZTF SLRN-2020
The spectra denoted by †
were stacked together to obtain the final binned late-time NIR spectrum.
19. Extended Data Table 3 | Derived dust parameters from the multi-epoch DUSTY modeling of ZTF SLRN-2020
The inner shell radius and ejecta mass are for an estimated distance of 4 kpc.