On the hierarchical triple nature of the former red nova precursor candidate KIC 9832227

Gaspar A. Bakos; Geza Kovacs; Joel D. Hartman

REVIEW 3 major objections 4 minor 12 references

On the hierarchical triple nature of the former red nova precursor candidate KIC 9832227

T0 review · 3 major / 4 minor · reviewed 2026-08-14 · deepseek-v4-flash

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Pith's one-line read KIC 9832227's eclipse times fit a slow period decrease plus a 13.5-year sinusoidal wobble, pointing to a third star rather than an imminent merger.

desk verdict Solidly kills the 2022 merger prediction; the tertiary interpretation is plausible but the period error is underestimated. read the letter →

arxiv 1909.00255 v1 pith:WF4UPTYL submitted 2019-08-31 astro-ph.SR

Geza Kovacs , Joel D. Hartman , Gaspar A. Bakos This is my paper · ORCID

classification astro-ph.SR

keywords KIC9832227eclipsetimingvariationO-CdiagramhierarchicaltriplerednovaprecursorWUMabinarylight-timeeffectperiodchange

verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

KIC 9832227, a W UMa-type contact binary (two stars sharing an outer envelope), was announced as a red nova precursor whose merger would produce an outburst around 2022. This paper re-examines the eclipse-timing record with 39 minima spanning about 19 years and claims that the timing variation is a steady, slow period decrease plus a sinusoidal wobble with period $4925\pm142$ days and amplitude $10.98\pm0.37$ minutes. The wobble is read as the light-time effect of a low-mass third star on a roughly 13.5-year orbit around the binary, with minimum mass $0.38\pm0.02$ solar masses. The period decrease of about $1.1\times10^{-6}$ days per year is ordinary for such binaries and orders of magnitude gentler than in V1309 Sco, the one confirmed pre-nova. If the paper is right, KIC 9832227 is a hierarchical triple, and the predicted 2022 red nova is not coming.

What carries the argument

The load-bearing tool is the O-C diagram, the difference between observed and calculated times of primary minimum plotted against time. The paper models this difference as $O-C = c_1 + c_2 t + c_3 t^2 + c_4 \sin(2\pi t/P_2) + c_5 \cos(2\pi t/P_2)$, where the quadratic encodes a steady period change and the sinusoid encodes a periodic clock wobble. The best-fit period $P_2 = 4925\pm142$ days and amplitude of about 11 minutes are then converted, through the light-travel-time geometry of a three-body system, into a minimum mass for the outer companion. The eclipse times themselves come from fourth-order Fourier fits and template fits to segmented light curves, with the extraction method chosen by minimizing the residual of this same model; the quadratic-plus-sinusoid form fits the data better than pure polynomials of comparable order.

What would settle it

Keep measuring eclipse times for the next three to four years: the model predicts the sinusoidal contribution, now near its minimum, will turn around and rise by several minutes, bending the O-C curve upward. If the curve instead continues its old exponential plunge or shows no turnaround, the hierarchical-triple interpretation is refuted; a radial-velocity search for a roughly 0.4-solar-mass companion on a 13.5-year orbit could also confirm or contradict the timing mass.

Watch

Extended reading notes

Core claim

The paper's claim, stated as a fair reader would hear it, is that the earlier red-nova prediction for KIC 9832227 rested on a mistimed early data point, and that the full eclipse-timing record tells a different story. Decomposing the observed-minus-calculated eclipse times into a quadratic plus a sinusoid leaves a residual scatter of 1.38 minutes; the sinusoid has period $4925\pm142$ days and amplitude $10.98\pm0.37$ minutes, while the quadratic term implies the orbital period is shrinking by $(1.10\pm0.05)\times10^{-6}$ days per year. The sinusoidal term is interpreted as the light-time effect of a third component on a $\sim$13.5-year orbit, giving a minimum mass of $0.38\pm0.02$ solar masses, which is consistent with the upper limit of 0.5 solar masses set by the non-detection of the star in spectroscopic line-broadening analysis. The measured period-decrease rate places the binary in the normal range of contact binaries, far from the extreme rate seen in V1309 Sco before its outburst. The conclusion: the timing data support a hierarchical triple, not an imminent merger.

Load-bearing premise

The load-bearing premise is that the 13.5-year sinusoidal wobble is a real, stable timing signal caused by an orbiting companion, rather than an artifact of how the eclipse times were measured or a magnetic activity cycle; if that wobble is not intrinsic, the companion and the hierarchical-triple interpretation collapse even though the curve fits well.

Editorial extensions

If this is right

The predicted red nova of 2022 should not occur; the exponential timing trend behind it came from an erroneous early epoch.
Eclipse timings over the next several years can test the model directly, because the sinusoidal component should pass its minimum and start rising by minutes.
The minimum companion mass of 0.38 solar masses fits below the spectroscopic non-detection limit, so the third star can be a normal low-mass star without having been seen.
The measured period decrease places KIC 9832227 in the normal range of contact binaries rather than in the extreme regime of the confirmed pre-nova V1309 Sco.
A white-dwarf third component remains possible but would create an ultraviolet excess that future short-wavelength observations can confirm or rule out.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

If this interpretation holds, other red-nova precursor candidates identified mainly by a steep quadratic timing trend should be checked for a cyclic component before merger predictions are made.
The 19-year baseline covers only about 1.4 cycles of the 13.5-year period, so the companion period is not tightly pinned; a second full cycle of timings would separate a true companion from a magnetic activity cycle of similar length.
The white-dwarf scenario, suggested by an ultraviolet excess, can be tested sooner than the next timing minimum: far-UV spectroscopy would reveal a hot roughly 30,000 K white dwarf while a cool main-sequence star would not.
If the companion is real, its light-time signal should appear as a slow acceleration of the binary's center of mass; combining eclipse timings with radial velocities would yield the full three-dimensional orbit and a true mass rather than a minimum mass.

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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Desk Editor's Note

read the letter

Short version: this paper settles the immediate question—KIC 9832227 is not going to merge in 2022—and that part is solid. The broader claim that the timing variations are best explained by a ~13.5-yr tertiary is plausible but not as strong as the abstract says. The reader and the stress-test note are right to push back on the quoted period error.

What the paper does well: it assembles a much larger dataset than the earlier work, including HATNet and WASP points that fill the crucial pre-2012 gap. Those points alone kill the exponential model of Molnar et al.; the merger prediction was an artifact of a bad early epoch plus an extrapolated fit. The O-C table is complete, all five measurement methods are reported, and the MCMC check is a nice sanity test. That is honest, reproducible work.

Where it gets soft: the sinusoidal part of the fit is the load-bearing evidence for the tertiary, and that part is fragile in exactly the way the stress-test note says. The quoted P2 = 4925 ± 142 d is from one template chosen by minimizing the same residual, and Table 2 shows the other equally defensible choices give periods from ~4700 to ~6000 d. The real uncertainty on P2 is hundreds of days, not 142. The Applegate rejection is also thin: one empirical activity diagram with the target as an outlier is not a direct test of magnetic-cycle modulations at 13.5 yr. So while the fit quality is good, the data do not "strongly support" a specific triple solution. They support a periodic component of some kind, and the third-body interpretation is the most economical—but alternatives are not excluded.

Also worth noting: the paper itself is honest about the ambiguity. The text flags the template dependence and the limitation statements are there. The overstatement is mainly in the abstract and conclusions.

Bottom line: for anyone working on red nova precursors or O-C methods, this is worth citing and worth a careful read. It corrects the record and provides a clean dataset. The specific companion mass and period should be treated as provisional until the predicted O-C turn-around is seen or a spectroscopic detection is made.

Recommendation: send to peer review. A good referee should ask for the abstract to be toned down and for the analysis to include the method-to-method spread in the quoted uncertainties, but the paper's central negative result is real and useful.

Referee Report

3 major / 4 minor

Summary. The paper revisits the eclipse-timing history of the W UMa binary KIC 9832227, the former red-nova precursor candidate, using 39 eclipse epochs assembled from Kepler, HATNet, WASP, ASAS-SN, AAVSO, WISE, and earlier surveys. The authors show that the early HATNet/WASP/NSVS points break the exponential period-decrease trend of Molnar et al. (2017) and that the O-C curve is instead well described by a quadratic plus a sinusoidal term with P2 = 4925 ± 142 d and amplitude 10.98 ± 0.37 min. They interpret this as evidence for a distant low-mass companion with minimum mass 0.38 ± 0.02 Msun, consistent with the spectroscopic upper limit of Molnar et al. (2017), and conclude that KIC 9832227 is probably a hierarchical triple rather than an imminent red nova.

Significance. If the conclusion holds, the paper settles a widely publicized question: KIC 9832227 is not on the verge of a red-nova merger, in agreement with the earlier retraction by Socia et al. (2018). The analysis is valuable because it adds substantial new data (HATNet, WASP, ASAS-SN, AAVSO, WISE) to fill a previously sparsely covered early epoch, and the rejection of the exponential model is convincing: the low-luminosity data points near HJD-2455000.0 = -2000 alone suffice to falsify the short-timescale merger hypothesis. The paper also gives honest error estimates via Monte Carlo, provides an MCMC cross-check of the least-squares solution, constructs a multi-band SED to test the tertiary hypothesis, and makes a falsifiable prediction (the O-C should turn upward within 3-4 years). These strengths are real and make the paper a useful contribution to the eclipsing-binary and red-nova literature.

major comments (3)

[Sec. 3, Table 2] The quoted period P2 = 4925 ± 142 d is derived from a single adopted method/template (OC4, Kepler-4) that was selected specifically because it minimized the residual of this same model (Sec. 2 and Sec. 3). Table 2 shows that five other equally defensible O-C constructions yield best-fit periods of 4683 ± 276, 5045 ± 492, 5206 ± 243, 5427 ± 266, and 5990 ± 747 d. The method-to-method spread of about 1300 d is an order of magnitude larger than the reported 142 d statistical error. The abstract's "~13.5 years" and the text's "P2 = (4925 ± 142) d" therefore overstate the precision. The authors should either report a systematic error that includes the Table 2 spread, or explicitly justify why the Kepler-4 template is the uniquely correct choice.
[Sec. 3, paragraph on polynomial comparison] The sinusoidal component is not strongly preferred over a non-periodic alternative by fit quality alone. The paper reports that a 5th-order polynomial reaches RMS = 1.46 min versus 1.38 min for the polynomial + sinusoid model, with the same number of free parameters. With 39 data points, this difference is not statistically compelling, and the baseline of 6900 d covers only about 1.4 cycles of the 4925 d period, leaving a partial degeneracy between the sinusoid and the quadratic term. To support the central claim that the data 'strongly support' a tertiary, the authors should apply a model-selection criterion (e.g., AIC/BIC or an F-test) and show that the sinusoid is required even when the competing polynomial of the same order is considered. As written, the fit alone does not discriminate the light-time effect from a non-periodic trend.
[Sec. 4, Fig. 8] The exclusion of the Applegate mechanism is fragile. The argument rests on the target's outlier position in an empirical activity-cycle diagram (Fig. 8), with the non-stringent assumption that the orbital period is a proxy for the rotation period, and the authors themselves note that the trend may not extend to the poorly populated parameter regime. No direct test for a ~13.5-year photometric modulation in the 19 years of light-curve data is presented, even though such a modulation would be a natural signature of the Applegate effect and is checkable with the existing ASAS-SN/AAVSO data. Until a direct test is made, stellar activity remains an unexcluded alternative to the light-time effect, and the word 'strongly' in the abstract is not justified.

minor comments (4)

[Sec. 2] The choice of OC4 as the adopted column is a post-fit selection (the template is chosen to minimize the O-C model residual). Please report the best-fit parameters for at least one Fourier-based column (e.g., OC1) in Table 3 to demonstrate that the qualitative conclusions (Pdot ~ -1.1e-6 d/yr, amplitude ~ 11 min, M3 >= 0.38 Msun) are insensitive to the O-C method.
[Sec. 3, Eq. (3)] The sentence 'Although the above formula is exact, it lacks accounting for the error introduced by the period P2' is slightly awkward; to improve clarity, rephrase as 'Although exact, Eq. (3) does not account for the uncertainty in P2; we therefore also include Monte Carlo propagation of the period error.'
[Sec. 4, mass estimate] The derived value M3 ≥ 0.38 ± 0.02 Msun is a lower limit, and the paper correctly calls it this. The wording 'the conformity of the derived minimum mass ... with the limit posed by the spectroscopic non-detection' is accurate, but consider noting explicitly that the comparison is only meaningful if the tertiary is a main-sequence star, which the paper later tests via the SED.
[Appendix C, Table C.1] The error for WISE W4 is listed as 9.999 mag, which appears to be a typographical error (the typical W4 uncertainty for this source is much smaller, and a 10-mag error is implausible). Please correct the entry or explain the value.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the third-body interpretation is a fitted physical model with external consistency checks, not a definitional reduction.

full rationale

The paper's derivation chain is a standard empirical modeling exercise. It collects eclipse times from independent surveys, derives O-C values via Fourier/template fits, fits a quadratic-plus-sinusoid model (Eq. 2), and then interprets the sinusoidal term as a light-time effect to derive a minimum companion mass. The mass is not an input to the model; it is computed from the fitted amplitude and period using Kepler's third law. The consistency check against the spectroscopic upper limit of 0.5 Msun from Molnar et al. (2017) is an external constraint, not an assumption built into the fit. The authors do not rename a known result or invoke a uniqueness theorem, and the HATNet data and related self-citations are data sources and methodological references rather than load-bearing circular support. The paper explicitly labels the future O-C behavior as a prediction with quantified uncertainty, and the method-selection step (choosing the template that minimizes residual scatter) is a model-selection caveat rather than a definitional circularity: the fitted parameters are not constructed to be equal to the inputs by definition. No step in the paper reduces to its own inputs, so the circularity score is 0.

Assumptions & free parameters 4 free parameters · 4 assumptions · 1 invented entities

The central model rests on four fitted parameters (P2, amplitude, quadratic coefficient, nuisance terms) plus three main assumptions: circular outer orbit, inner binary mass from Molnar et al. (2017), and unbiased O-C errors. The third body is inferred, not detected, but is constrained by an external spectroscopic upper limit and by future timing predictions.

free parameters (4)

P2 (outer modulation period) = 4925 +/- 142 d (LS); 4941 +/- 191 d (MCMC)
Fitted by a period scan over 4000-8000 d (Fig. 5); the central parameter of the triple interpretation. The method-to-method spread (4683-5990 d) is larger than the quoted error.
Ampl (O-C sinusoidal amplitude) = 10.98 +/- 0.37 min
From fitted coefficients c4 and c5 (Table 3); used with P2 to derive the third-body minimum mass.
c3 (quadratic O-C coefficient) = (-2.1632 +/- 0.0921) x 10^-6 min/d^2
Gives Pdot = -1.097 +/- 0.047 x 10^-6 d/yr; the monotonic period change component.
c1, c2 (constant and linear O-C coefficients) = c1 = -0.7626 +/- 0.3838; c2 = -0.015618 +/- 0.000146
Nuisance parameters of the linear regression; listed for completeness.

assumptions (4)

domain assumption The outer orbit is circular (zero eccentricity).
Used in Sect. 4 to convert the sinusoidal amplitude to M3 via the light-time mass function. Justified by small e cos omega from primary/secondary O-C differences and by the circular RV fit, but not individually measured.
domain assumption The total mass of the inner W UMa binary is taken from Molnar et al. (2017).
Converting the mass function to M3 requires the inner binary mass M_AB; the paper cites Molnar et al. (2017) for this input and does not derive it. A 10% error in M_AB changes M3 by a few percent.
domain assumption The O-C values from the chosen template (OC4, Kepler-4) are unbiased, and the Monte Carlo errors are realistic.
The template was selected to minimize the residual of the same model being fitted (Sect. 2); Table 2 shows P2 depends on the method, so the quoted 1-sigma errors do not cover method-to-method systematics.
domain assumption The 13.5-yr sinusoidal term arises from period variation, not from light-curve morphology changes or a windowing artifact.
Non-stationary W UMa light curves can shift apparent eclipse times (spot-driven jitter of 1-2 min); the model attributes the 11-min wobble to a genuine period variation. The paper mitigates with template fitting but cannot fully exclude a morphological mimic.

invented entities (1)

Third body around KIC 9832227 (minimum mass ~0.38 Msun) independent evidence
purpose: Explains the ~13.5-year sinusoidal O-C variation via the light-time effect; not directly detected.
The model predicts the O-C curve reaches a minimum and turns upward within 3-4 years from publication (Fig. 7), a falsifiable timing forecast; future spectroscopy could directly detect the companion, and the white-dwarf variant predicts UV excess. Hence it has a falsifiable handle outside the fitted data.

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Cite this review

Pith. "Pith review of On the hierarchical triple nature of the former red nova precursor candidate KIC 9832227." pith.science (2026). https://pith.science/paper/WF4UPTYL

@misc{pith2026190900255,
  author       = {Pith},
  title        = {Pith review of: On the hierarchical triple nature of the former red nova precursor candidate KIC 9832227},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/WF4UPTYL}},
  note         = {Machine review of arXiv:1909.00255}
}

read the original abstract

We revisit the issue of period variation of the recently claimed red nova precursor candidate KIC 9832227. By using the data gathered during the main mission of the Kepler satellite, those collected by ground-based wide-field surveys and other monitoring programs (such as ASAS-SN), we find that the currently available timing data strongly support a model consisting of the known W UMa binary and a distant low-mass companion with an orbital period of ~13.5 years. The period of the W UMa component exhibits a linear period decrease with a pace of (1.10+/-0.05)x10^{-6} days per year, within the range of many other similar systems. This rate of decrease is several orders of magnitude lower than that of V1309 Sco, the first (and so far the only) well-established binary precursor of a nova observed a few years before the outburst. The high-fidelity fit of the timing data and the conformity of the derived minimum mass of (0.38+/-0.02) Msun of the outer companion from these data with the limit posed by the spectroscopic non-detection of this component, are in agreement with the suggested hierarchical nature of this system.

Figures

Figures reproduced from arXiv: 1909.00255 by the authors.

**Figure 1.** Comparison of the folded light curves and the corresponding 4-th order Fourier fits (continuous lines) for the HATnet and Kepler observations on KIC 9832227. We use the adjacent datasets corresponding to Tmid = 875 and 878, as given in [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗

**Figure 3.** Fourier-fitted synthetic light curves of all the 37 data segments analyzed in this paper. The primary minima are shifted to zero phase. The time series are ordered on the basis of the closest neighbor as described in Sect. 2. The pre-selected templates are shown by distinct colors. Following the notation of [PITH_FULL_IMAGE:figures/full_fig_p003_3.png] view at source ↗

**Figure 5.** Period scan of the O-C data obtained by the template fit method (see column OC4 of [PITH_FULL_IMAGE:figures/full_fig_p005_5.png] view at source ↗

Figures from the paper (5 more)

**Figure 7.** Figure 7: Polynomial+sinusoidal fit (thick black line) of the observed O-C values (yellow dots, OC4 of [PITH_FULL_IMAGE:figures/full_fig_p006_7.png]

**Figure 6.** Figure 6: Result of the joint fit of a second order polynomial and a single sinusoidal to the data shown [PITH_FULL_IMAGE:figures/full_fig_p006_6.png]

**Figure 8.** Figure 8: Position of KIC 9832227 (light blue dot) on the schematic diagram relating the rotation frequency to the ratio of the period of the long-term cyclic luminosity variation due to stellar activity to the rotation period. The shaded area cover the data points shown by Alm…

**Figure 9.** Figure 9: Comparison of the observed and theoretical SEDs for KIC 9832227. Dots denote observed values, with 3σ vertical error bars, and equivalent waveband widths (horizontal bars). The inset shows the various theoretical SEDs: F1 - primary only, F2 - secondary only, F1+F2 - b…

**Figure 10.** Figure 10: Comparison of the size of the observed period changes of various groups of binaries. The verified pre-nova V1309 Sco stands out with its huge rate and its change within six years of observing time span. On the other hand, KIC 9832227 sits right in the middle of the bi…

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

12 extracted references · 11 canonical work pages

[1]

P ., Abbott, R., Abbott, T

Abbott, B. P ., Abbott, R., Abbott, T. D. et al. 2016, Phys. Rev. Lett., 116, 061102 Almeida, L. A.,de Almeida, L., Damineli, A. et al. 2019 AJ, 15 7, 150 Apellaniz, J. M. & Gonzalez, M. P . 2018, A&A, 616, L7 Applegate, J. H. 1992, ApJ, 385, 621 Bakos, G.; Noyes, R. W.; Kov´ acs, G., et al. 2004, PASP , 116, 266 Bakos, G. ´A., Torres, G., P´ al, A., et a...

arXiv 2016
[2]

(2018) (as a result, all OC values are the same for these items)

First we note that the values for the Vulcan and MLO data have been taken from Socia et al. (2018) (as a result, all OC values are the same for these items). In the case of the AA VSO data, we used only V and I observations, because other colors did not have proper phase coverage. The web sites and the appropriat e journal references for the data sources ...

work page 2018
[3]

By performin g these campaign- and ﬁlter-dependent shifts, we ended up wit h a time series containing 116 items

01 mag, that depends also on which of the above two campaigns is considered. By performin g these campaign- and ﬁlter-dependent shifts, we ended up wit h a time series containing 116 items. In spite of the above adju st- ments, the data still show signiﬁcant scatter of 0 . 028 mag around a 4-th order Fourier ﬁt. Nevertheless, the accuracy of the O- C valu...

work page 2006
[5]

Best-ﬁt parameters of the polynomial +sinusoidal model by MCMC

To derive dereddened magni- tudes, we accepted the reddening given by the map of Schlaﬂy & Finkbeiner (2011) and accessible at the NASA /IP AC Infrared 4 https://vizier.u-strasbg.fr/viz-bin/VizieR 5 http://svo2.cab.inta-csic.es/theory/fps/ 10 Kovacs, Hartman & Bakos: The hierarchical system KIC 983222 7 T able B.1. Best-ﬁt parameters of the polynomial +si...

work page 2011
[6]

(2014) were used

Extinction in any given waveband has been computed by Aλ = RλE(B − V), where the extinction coe ﬃcients Rλgiven by Y uan, Liu & Xiang (2013), Sanders & Das (2018), Liu & Janes (1990) and Davenport et al. (2014) were used. For the XMM-Newton UVW1 band, we employed the Y ork Extinction Solver 7 (see McCall 2004). All these input data to construct the observ...

work page 2013
[7]

(2016) yields E(B − V) =

The MWDust tool by Bovy et al. (2016) yields E(B − V) =

work page 2016
[9]

We note that the reddening value for KIC 9832227 is far from accurate – in spite of the small formal error bar of the value we used

are listed in Table C.1. We note that the reddening value for KIC 9832227 is far from accurate – in spite of the small formal error bar of the value we used. Molnar et al. (2017) compare the spectroscopi c and color-calibrated Teﬀ values to derive a considerably lower value of E(B − V) =

work page 2017
[10]

The Gaia and the WISE magnitudes are deﬁned on the V ega system 8, so their observed and trans- formed values are the same

5 log(ZP/ 3631), where the zero point ZP for the given waveband was taken from the Spanish Visual Observatory site. The Gaia and the WISE magnitudes are deﬁned on the V ega system 8, so their observed and trans- formed values are the same. The AP ASS magnitudes are in the Johnson system, that can be transformed to the AB system base d on Frei & Gunn (1994)

work page 1994

Show all 12 references

[11]

Then, these magnitudes were trans- formed to the V ega system as already mentioned above. The 2MASS magnitudes are nearly on the V ega system, but, ac- cording to Apellaniz & Gonzalez (2018), there might be some systematic diﬀerences, yielding the following shifts to the pub- ...

2018
[12]

These models are without con- vective overshooting (see Castelli, Gratton & Kurucz 1997)

25 and 2 km /s, respectively. These models are without con- vective overshooting (see Castelli, Gratton & Kurucz 1997). The current Gaia distance of 585 ± 10 pc and the radii of Molnar et al. (2017) (1.58 R ⊙ and 0.83 R ⊙ for the primary and secondary component, respectively) ...

2017
[13]

The parameters for the white dwarf model are broadly consistent with the model valu es of Romero et al

downloaded from the site cited above. The parameters for the white dwarf model are broadly consistent with the model valu es of Romero et al. (2019) at the temperature chosen, and assumi ng a mass of M ∼

2019
[21]

Exceeding all these val- ues, by using the extinction coeﬃcients of Wang & Chen (2019), the Gaia catalog yields E(B − V) =

2019

Pith tools

Reviewed August 14, 2026 · model on record in the stance chip above.

[1] [1]

P ., Abbott, R., Abbott, T

Abbott, B. P ., Abbott, R., Abbott, T. D. et al. 2016, Phys. Rev. Lett., 116, 061102 Almeida, L. A.,de Almeida, L., Damineli, A. et al. 2019 AJ, 15 7, 150 Apellaniz, J. M. & Gonzalez, M. P . 2018, A&A, 616, L7 Applegate, J. H. 1992, ApJ, 385, 621 Bakos, G.; Noyes, R. W.; Kov´ acs, G., et al. 2004, PASP , 116, 266 Bakos, G. ´A., Torres, G., P´ al, A., et a...

arXiv 2016

[2] [2]

(2018) (as a result, all OC values are the same for these items)

First we note that the values for the Vulcan and MLO data have been taken from Socia et al. (2018) (as a result, all OC values are the same for these items). In the case of the AA VSO data, we used only V and I observations, because other colors did not have proper phase coverage. The web sites and the appropriat e journal references for the data sources ...

work page 2018

[3] [3]

By performin g these campaign- and ﬁlter-dependent shifts, we ended up wit h a time series containing 116 items

01 mag, that depends also on which of the above two campaigns is considered. By performin g these campaign- and ﬁlter-dependent shifts, we ended up wit h a time series containing 116 items. In spite of the above adju st- ments, the data still show signiﬁcant scatter of 0 . 028 mag around a 4-th order Fourier ﬁt. Nevertheless, the accuracy of the O- C valu...

work page 2006

[4] [5]

Best-ﬁt parameters of the polynomial +sinusoidal model by MCMC

To derive dereddened magni- tudes, we accepted the reddening given by the map of Schlaﬂy & Finkbeiner (2011) and accessible at the NASA /IP AC Infrared 4 https://vizier.u-strasbg.fr/viz-bin/VizieR 5 http://svo2.cab.inta-csic.es/theory/fps/ 10 Kovacs, Hartman & Bakos: The hierarchical system KIC 983222 7 T able B.1. Best-ﬁt parameters of the polynomial +si...

work page 2011

[5] [6]

(2014) were used

Extinction in any given waveband has been computed by Aλ = RλE(B − V), where the extinction coe ﬃcients Rλgiven by Y uan, Liu & Xiang (2013), Sanders & Das (2018), Liu & Janes (1990) and Davenport et al. (2014) were used. For the XMM-Newton UVW1 band, we employed the Y ork Extinction Solver 7 (see McCall 2004). All these input data to construct the observ...

work page 2013

[6] [7]

(2016) yields E(B − V) =

The MWDust tool by Bovy et al. (2016) yields E(B − V) =

work page 2016

[7] [9]

We note that the reddening value for KIC 9832227 is far from accurate – in spite of the small formal error bar of the value we used

are listed in Table C.1. We note that the reddening value for KIC 9832227 is far from accurate – in spite of the small formal error bar of the value we used. Molnar et al. (2017) compare the spectroscopi c and color-calibrated Teﬀ values to derive a considerably lower value of E(B − V) =

work page 2017

[8] [10]

The Gaia and the WISE magnitudes are deﬁned on the V ega system 8, so their observed and trans- formed values are the same

5 log(ZP/ 3631), where the zero point ZP for the given waveband was taken from the Spanish Visual Observatory site. The Gaia and the WISE magnitudes are deﬁned on the V ega system 8, so their observed and trans- formed values are the same. The AP ASS magnitudes are in the Johnson system, that can be transformed to the AB system base d on Frei & Gunn (1994)

work page 1994