J/A+A/706/A154 Study of 9 LRNe with various photometric data (Reguitti+, 2026)
The fate of the progenitors of luminous red novae:
Infrared detection of LRNe years after the outburst.
Reguitti A., Pastorello A., Valerin G.
<Astron. Astrophys. 706, A154 (2026)>
=2026A&A...706A.154R 2026A&A...706A.154R (SIMBAD/NED BibCode)
ADC_Keywords: Novae ; Photometry ; Infrared
Keywords: techniques: photometric - binaries: close - binaries: general -
supernovae: general - dust, extinction
Abstract:
We present late-time optical and infrared (IR) observations of a
sample of nine extragalactic luminous red novae (LRNe) discovered in
the past three decades. In all of these cases, the LRN survivors fade
below the pre-outburst luminosity of the progenitors in the optical
region. However, they remain visible in the near-IR (NIR) and bright
in the mid-IR (MIR) domains for years. We recover AT 1997bs in Spitzer
images from 2004, and a residual source is visible in HST and JWST NIR
images 27 years after the outburst. The spectral energy distribution
(SED) of AT 1997bs is consistent with that of an orange giant star
with a photospheric temperature of 3750-4250K and a radius of
120-150R☉, without a significant circumstellar dust attenuation.
Similarly, the SED of AT 2019zhd after three years is compatible with
a red supergiant star with Tph∼3100±100K and R∼350±50R☉.
Another LRN, AT 2011kp, is detected by JWST 12.5 years after the
outburst. Its SED, with two excesses at 1.8 and 7.7µm, can be
explained by a cold (T∼450K) dusty shell composed of amorphous carbon
surrounding a cold expanded source, plus emission from the Paα
line. We constructed the [3.6]-[4.5] colour curves extending up to
more than 7 years for six LRNe, which show a similar evolution: The
MIR colour is ~-0.5mag before the optical maximum light, it becomes
bluer after around one year, and then it gradually turns to redder
colours in the following years before reaching [3.6]-[4.5]~+1.0mag 7
years after the outburst. We also estimated the masses and the
temperatures of newly formed dust years after the LRN onset. We find
that LRNe produce dust masses of the order of (1-5)*10-4 (and up to
2*10-3) M☉ between 7 and 13 years after the outbursts.
Finally, we find that the remnants of LRNe detected years or decades
after the merger tend to be expanded and cool objects, similar to red
supergiant stars.
Description:
We analyse a sample of nine extragalactic LRNe documented in the
literature (i.e the table.dat). Only objects at least five years old
(the oldest was discovered in 1997) in 2025 are considered. The fields
of our targets were observed by space telescopes, preferentially in
the IR domain. The imaging data analysed in this paper were obtained
with different space facilities, including HST, WFPC2, WFC3, ACS, SST,
IRAC, WISE, NEOWISE, JWST, NIRCam and MIRI (i.e see sections
observations and results). Magnitudes, object names, magnitude system
and instruments are presented in table.dat.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
lrne.dat 36 9 Extragalactic luminous red nova sample
table.dat 61 148 Photometry magnitudes for the nine extragalactic
luminous red novae
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See also:
J/A+A/695/A42 : Data collected for 4 ILRTs (Valerin+, 2025)
J/A+A/686/A45 : Binary mass transfer model data (Schneider+, 2024)
J/A+A/671/A158 : Three luminous red novae light curves (Pastorello+, 2023)
J/A+A/667/A4 : NGC4631 luminous red nova AT 2021biy light curves (Cai+, 2022)
J/A+A/654/A157 : 5 ILRTs light curves and spectra (Cai+, 2021)
J/A+A/653/A134 : AT 2018bwo light curves (Blagorodnova+, 2021)
J/A+A/647/A93 : AT 2020hat and AT 2020kog light curves (Pastorello+, 2021)
J/A+A/646/A119 : M31 luminous red nova AT 2019zhd photometry (Pastorello+,2021)
J/A+A/632/L6 : AT 2018hso light curves and spectra (Cai+, 2019)
J/A+A/630/A75 : Six luminous red novae photometry (Pastorello+, 2019)
J/A+A/625/L8 : SN 2017jfs optical and NIR light curves (Pastorello+, 2019)
J/A+A/418/869 : M31-RV evolution (1942-1993) (Boschi+, 2004)
J/ApJ/894/111 : Gemini/GMOS-S spectra of the type IIn SN 2010jl (Bevan+, 2020)
J/ApJ/834/107 : Follow-up photometry of M101 OT2015-1 (Blagorodnova+, 2017)
J/ApJ/792/30 : NEOWISE magnitudes for near-Earth objects (Mainzer+, 2014)
II/349 : The Pan-STARRS release 1 (PS1) Survey - DR1 (Chambers+, 2016)
Byte-by-byte Description of file: lrne.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Object names of the extragalactic luminous
red novae LRNe (Object)
11- 12 I2 h RAh Right Ascension (J2000)
14- 15 I2 min RAm Right Ascension (J2000)
17- 21 F5.2 s RAs Right Ascension (J2000)
23 A1 --- DE- Declination sign (J2000)
24- 25 I2 deg DEd Declination (J2000)
27- 28 I2 arcmin DEm Declination (J2000)
30- 33 F4.1 arcsec DEs Declination (J2000)
35- 36 I2 --- Nbr Number of occurence in table.dat
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Byte-by-byte Description of file: table.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Object names of the extragalactic luminous red
novae LRNe (Object)
11- 21 F11.5 d MJD Modified julian date (MJD)
23- 28 A6 --- Filter Photometric filter (Filter)
30- 33 A4 --- System [vega ab] Photometric system (System)
35- 40 F6.3 mag mag Apparent magnitude (Mag)
42- 46 F5.3 mag e_mag Uncertainty of the magnitude (eMag)
48 A1 --- Det [P U] Detection flag P=yes and U=no
(Detection)
50- 61 A12 --- Inst Instrument used (Instrument) (1)
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Note (1): Space instrument facilities are as follows:
Spitzer/IRAC = The Spitzer Space Telescope (SST) with the Infrared
Array Camera (IRAC), 77 occurences in our sample
WISE/WISE = The Wide Infrared Space Explorer (WISE) during the
Near-Earth Object WISE (NEOWISE) mission,
35 occurences in our sample
JWST/NIRCam = The James Webb Space Telescope (JWST) with the Near
Infrared Camera (NIRCam), 11 occurences in our sample
HST/WFC3 = The Hubble Space Telescope with the Wide Field
Camera 3 (WFC3), 9 occurences in our sample
HST/ACS = The Hubble Space Telescope with the Advanced Camera
for Surveys, 7 occurences in our sample
JWST/MIRI = The James Webb Space Telescope (JWST) with the
Mid-Infrared Instrument (MIRI), 6 occurences in our
sample
UKIRT/WFCAM = The United Kingdom Infrared Telescope (UKIRT) with
the Wide Field Camera (WFCAM), 1 occurence in our
sample
PTF/MOSAIC = The Palomar Transient Factory with the mosaic ccd
camera (MOSAIC), 1 occurence in our sample
CFHT/MegaPr = The Canada France Hawaii Telescope with the wide-field
optical imaging MegaPrime camera (MegaPrime),
1 occurence in our sample
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Acknowledgements:
Andrea Reguitti, andrea.reguitti(at)inaf.it
(End) Andrea Reguitti [INAF], Luc Trabelsi [CDS] 11-Dec-2025