J/A+A/653/A134 AT 2018bwo light curves (Blagorodnova+, 2021)
The luminous red nova AT 2018bwo in NGC 45 and its binary yellow
supergiant progenitor.
Blagorodnova N., Klencki J., Pejcha O., Vreeswijk P.M., Bond H.E.,
Burdge K.B., De K., Fremling C., Gehrz R.D., Jencson J.E., Kasliwal M.M.,
Kupfer T., Lau R.M., Masci F.J., Rich R.M.
<Astron. Astrophys. 653, A134 (2021)>
=2021A&A...653A.134B 2021A&A...653A.134B (SIMBAD/NED BibCode)
ADC_Keywords: Novae ; Binaries, cataclysmic ; Binaries, orbits ; Mass loss ;
Photometry, ugriz ; Photometry, infrared ; Photometry, HST ;
Spectroscopy
Keywords: binaries: general - novae, cataclysmic variables -
stars: individual: AT 2018bwo - stars: winds, outflows -
stars: evolution - stars: flare
Abstract:
Luminous red novae (LRNe) are astrophysical transients associated with
the partial ejection of a binary system's common envelope (CE) shortly
before its merger. Here we present the results of our photometric and
spectroscopic follow-up campaign of AT 2018bwo (DLT 18x), a LRN
discovered in NGC 45, and investigate its progenitor system using
binary stellar-evolution models. The transient reached a peak
magnitude of Mr=-10.97±0.11 and maintained this brightness during
its optical plateau of tp=41±5d ays. During this phase, it showed
a rather stable photospheric temperature of ∼3300K and a luminosity of
∼1040erg/s. Although the luminosity and duration of AT 2018bwo is
comparable to the LRNe V838 Mon and M31-2015LRN, its photosphere at
early times appears larger and cooler, likely due to an extended
mass-loss episode before the merger. Toward the end of the plateau,
optical spectra showed a reddened continuum with strong molecular
absorption bands. The IR spectrum at +103 days after discovery was
comparable to that of an M8.5 II type star, analogous to an extended
AGB star. The reprocessed emission by the cooling dust was also
detected in the mid-infrared bands ∼1.5 years after the outburst.
Archival Spitzer and Hubble Space Telescope data taken 10-14yrs before
the transient event suggest a progenitor star with Tprog∼6500K,
Rprog∼100R☉, and Lprog=2x104L☉, and an upper limit
for optically thin warm (1000K) dust mass of Md<10-6M☉.
Using stellar binary-evolution models, we determined the properties of
binary systems consistent with the progenitor parameter space. For AT
2018bwo, we infer a primary mass of 12-16M☉, which is 9-45%
larger than the ∼11M☉ obtained using single-star evolution
models. The system, consistent with a yellow-supergiant primary, was
likely in a stable mass-transfer regime with -2.4 ≤ log (M_dot/Msun
/yr) ≤ -1.2 a decade before the main instability occurred. During the
dynamical merger, the system would have ejected 0.15-0.5M☉ with
a velocity of ∼500km/s.
Description:
Table1 contains the broadband optical and infrared photometry of AT
2018bwo. Sloan g,r,i bands, ATLAS c,o bands, and DLT40 Clear band are
in the AB mag system. Infrared and the Gaia measurements are in the
Vega mag system. The values were not corrected for extinction.
Objects:
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RA (2000) DE Designation(s)
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00 14 01.720 -23 11 35.84 AT 2018bwo = DLT 18x
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 50 86 *Photometry of AT 2018bwo
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Note on table1.dat: Broadband Sloan g,r,i, ATLAS c,o, DLT40 Clear photometry of
AT 2018bwo (AB mag system), and Gaia G, Spitzer IRAC [3.6],[4.5],
NEOWISE W1,W2, and Johnson J,H,Ks photometry (Vega mag system)
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Tel Telescope used to acquire the data (1)
9- 13 A5 --- Filter Photometric band (2)
15- 23 F9.3 --- MJD Modified Julian Date when the data was taken (3)
25- 29 F5.3 --- e_MJD Standard deviation on the MJDs used to bin the
photometric measurements (4)
31 A1 --- l_mag [>] Limit flag on mag
33- 38 F6.3 mag mag Magnitude in Filter
40- 44 F5.3 mag e_mag Magnitude error
46- 50 I5 --- ATel Number of the ATel if the data was obtained
from an external source
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Note (1): Telescopes are ATLAS, Gaia, Keck, LCO, P200, Prompt, Prompt5, Spec,
Spitzer and WISE.
Note (2): Photometric band as follows:
c = ATLAS c band (AB mag system)
o = ATLAS o band (AB mag system)
G = Gaia G band (Vega mag system)
H = Keck or P200 Johnson H band (Vega mag system)
J = Keck or P200 Johnson J band (Vega mag system)
K = Keck or P200 Johnson K band (Vega mag system)
g = LCO or Spec Sloan g band (AB mag system)
r = LCO or Spec Sloan r band (AB mag system)
i = LCO or Spec Sloan i band (AB mag system)
Clear = Prompt or Prompt5 clear band (AB mag system)
3.6 = Spitzer 3.6um band (Vega mag system)
4.5 = Spitzer 4.5un band (Vega mag system)
W1 = NEOWISE W1 band (3.6um) (Vega mag system)
W2 = NEOWISE W2 band (4.5um) (Vega mag system)
Note (3): For 1-day binned photometry, it is the average MJD for all the
measurements.
Note (4): It is zero for non-binned measurements.
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Acknowledgements:
Nadejda Blagorodnova: n.blagorodnova (at) astro.ru.nl
(End) Patricia Vannier [CDS] 24-Jun-2021