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SDSS-V's multi-epoch spectra of 5,185 DA white dwarfs yield 63 double-white-dwarf binary candidates and constrain the Galactic binary fraction to about 9% at separations under 0.4 AU.

Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →

SDSS-V radial velocity monitoring yields 63 DA double white dwarf binary candidates (43 new), with fitted binary fraction f_bin,0.4 ≈ 9% and separation power-law index α ≈ -0.62.

T0 review reviewed 2026-08-05 challenge →

load-bearing objection A valuable DWD catalog built on solid RV vetting, with population constraints that are conditional on an assumed low-mass binary fraction and should be reframed. the 2 major comments →

arxiv 2509.02906 v1 pith:WA5CBNWY submitted 2025-09-03 astro-ph.SR astro-ph.GA

Double White Dwarf Binaries in SDSS-V DR19 : A catalog of DA white dwarf binaries and constraints on the binary population

classification astro-ph.SR astro-ph.GA
keywords White dwarf starsBinary starsClose binary starsGravitational wave sourcesType Ia supernovaeLow mass starsRadial velocity
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

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

The reading

The paper reports a search for double white dwarf (DWD) binaries using the fifth-generation Sloan Digital Sky Survey (SDSS-V), which takes multiple 15-minute sub-exposures per target. The authors measure radial velocities for 5,185 hydrogen-atmosphere (DA) white dwarfs, quantify how much each star's velocity varies between exposures, and identify 63 DWD binary candidates, 43 of them new to the literature, with tentative orbital periods for 10 systems. They then build a mock SDSS-V observation of a simulated Galactic white dwarf population, assuming binaries form with a power-law separation distribution, and compare the predicted distribution of maximum velocity shifts to the observed one. The fit yields a binary fraction of 9% for white dwarfs with a companion within 0.4 AU and a power-law index alpha = -0.62 for the initial separation distribution. If these numbers hold, the sample should contain at most ten super-Chandrasekhar binaries that merge within a Hubble time, and the Milky Way should host 10,000-20,000 white dwarf binaries detectable by the LISA gravitational-wave mission. Because DWDs are candidate Type Ia supernova progenitors and the dominant millihertz gravitational-wave sources, these constraints connect a single survey to two long-standing questions: how white dwarf pairs form and merge, and what LISA will see.

Core claim

Using the radial velocities of 42,176 sub-exposures of 5,185 DA white dwarfs from SDSS-V DR19, the paper identifies 63 DWD binary candidates with eta>3 (where eta measures the significance of the observed velocity variability over spectral noise alone) and maximum velocity shifts exceeding 100 km/s. Forty-three of these are new discoveries. For ten candidates with good phase coverage, the Lomb-Scargle periodogram gives orbital periods, and three match previously published values. Comparing the observed Delta RV_max distribution with mock SDSS-V observations of simulated DWD populations, the authors constrain the fraction of white dwarfs in binaries with separation <0.4 AU to f_bin,0.4 = 9% (

What carries the argument

The analysis is carried by two linked tools. First, a radial-velocity variability statistic eta = -log(1 - P(chi^2 > chi^2_m)) built from the chi-squared scatter of each star's sub-exposure velocities about their weighted mean: a high eta means the star's velocity changed more than measurement noise can explain. Second, a forward model of the survey: masses are drawn from the SDSS DA white dwarf mass distribution, binaries are assigned separations from a power law n(a) proportional to a^alpha, gravitational-wave orbital decay reshapes the present-day separation distribution, mock observations are scheduled with the real SDSS-V cadence and error distribution, and the simulated Delta RV_max hi

Load-bearing premise

The constraints assume that nearly all very-low-mass white dwarfs (below 0.45 solar masses) live in binaries - 100% below 0.25 solar masses and 70% for 0.25-0.45 - so that 7.5% of all white dwarfs are low-mass binaries; if the true fraction is different, the inferred 9% binary fraction and alpha = -0.62 shift substantially.

What would settle it

Take the volume-limited 100 pc white dwarf sample, obtain high-precision radial velocities at multiple epochs for every DA white dwarf with Teff above 6000 K, and measure orbital periods for all systems whose velocities vary. If the fraction with separations below 0.4 AU deviates from 9%, or if the binarity fraction of low-mass (<0.45 solar masses) white dwarfs is far from the assumed 70-100%, the paper's population constraints would need to be revised.

Watch this falsifier. Get emailed when new claim-graph text bears on it.

If this is right

  • The roughly 58 real binaries expected after accounting for about five false positives would nearly double the sample of known DWDs available for orbital-solution follow-up.
  • The inferred binary fraction f_bin,0.4 = 9% and alpha = -0.62 give a DWD merger rate of about 2 x 10^-12 per year, about five times lower than earlier estimates, mainly because of the different underlying WD mass distribution used.
  • At most 10 super-Chandrasekhar DWDs that merge within a Hubble time are predicted in the SDSS-V sample, sharpening the search for Type Ia supernova progenitors.
  • Up to five systems in the catalog should be detectable by LISA in its first four years, including one already listed as a LISA verification source; the Galaxy as a whole should host 10,000-20,000 such sources.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The same RV-variability approach should transfer directly to other wide-field spectroscopic surveys that take multiple exposures per target, so the yield of DWD discoveries can be expected to grow with survey scale without dedicated binary-targeted observations.
  • Because the inferred f_bin and alpha hinge on the assumed binarity of low-mass WDs, independent campaigns measuring the binary fraction of low-mass WDs would tighten the population constraints more than merely collecting additional RV epochs.
  • If the Galaxy truly holds 10,000-20,000 LISA-detectable DWDs, LISA will provide a near-complete census of short-period DWDs, allowing a direct test of the formation model beyond the local SDSS sample.
  • The catalog already contains rare subtypes - a magnetic wide binary, a ZZ Ceti in a double-lined system, a debris-disk candidate - suggesting that follow-up of the 43 new candidates may uncover more such systems, not just more binaries.
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Editorial analysis

A structured set of objections, weighed in public.

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

Referee Report

2 major / 6 minor

Summary. This paper searches SDSS-V DR19 for DA white-dwarf binaries using radial-velocity variations among sub-exposures. CORV stellar-parameter fits provide RV errors calibrated with a pair-subtraction test; candidates are selected by the variability statistic η > 3, tuned against an RV-error-only simulation. The catalog contains 63 DWD candidates (43 new, about 5 expected false positives), with tentative periods for 10 systems, three of which match published orbits. The authors build a forward model of the SDSS-V observation pattern, draw binary populations with fixed binarity rules for low-mass WDs (100% below 0.25 M_sun, 70% at 0.25–0.45 M_sun), sample separations from a power law n(a) ∝ a^α with gravitational-wave orbital decay, and fit the ΔRVmax distribution of η > 3 objects to infer f_bin,0.4 = 0.09^{+0.03}_{-0.01} and α = −0.62 ± 0.10. They validate the pipeline against Badenes & Maoz (2012) and predict ≤ 10 super-Chandrasekhar merger progenitors, ≤ 5 LISA-detectable systems in the sample, and about 10,000–20,000 LISA-detectable Galactic DWDs.

Significance. If it holds, the catalog is a substantial community resource: 63 candidates with systematic RV-variability screening, calibrated errors, a reproducible methodology, and percent-level period recovery for three systems. The pair-subtraction error calibration, the η-threshold calibration, the Badenes–Maoz validation within 2σ, and the public catalog are concrete strengths. The population constraints are the paper's headline claim, and they are conditional on the assumed low-mass WD binary fraction—a dependence the authors themselves demonstrate in §6.2–6.3. The catalog claim does not depend on that assumption; the population claim does. With the conditional framing and the contamination/sampling issues addressed, this would be an important contribution to DWD population studies.

major comments (2)
  1. [Sec. 5.1–5.3, 6.2–6.3, Figs. 8–9] f_bin,0.4 = 0.09^{+0.03}_{-0.01} and α = −0.62 ± 0.10 are conditional on the hard-coded low-mass WD binarity (100% for m1 < 0.25 M_sun, 70% for 0.25–0.45 M_sun; Brown et al. 2011), which yields 7.5% of WDs as low-mass binaries. The authors' own hot-WD re-fit (T_eff > 12,000 K) gives a 2.8% low-mass binary fraction and shifts the contours to lower f_bin and α (Fig. 9); §6.3 states the volume-limited 100 pc sample implies 3.2% and 'constraints should be similar to Fig. 9'. The quoted errors are statistical only and exclude this demonstrated systematic; §5.3's 'we do not place joint constraints' acknowledges the limitation. Yet the abstract presents f_bin = 9% and α = −0.62 as the main population result, and the SNe-Ia/LISA predictions inherit the same conditioning. Please report results as conditional with a systematic bracketing the hot-WD/volume-limited cases, or fit the low-mass binary
  2. [Sec. 4.1, Table 1, Sec. 5.1] The sample used for the population fit retains six subdwarf/pre-ELM WD candidates (e.g., Gaia DR3 1017136594580182400, 3076962575704962176, 677695609668436736) that are not WDs under the model's mass–radius prescription, with companions not necessarily WDs. They enter the fitted ΔRVmax distribution, while the forward model assumes WD+WD systems. If these are not DWDs, the inferred f_bin,0.4 overestimates the DWD fraction. Exclude them or model their selection function, and quantify the effect on the contours.
minor comments (6)
  1. [Table 1] Gaia DR3 1017136594580182400 is labeled J150506.17+325959.4 with η = 79.06, duplicating the η = 12.57 row for that same name; Table 3 lists this source as J085252.86+514246.6 with η = 79.06. The J-name in Table 1 appears to be a copy-paste error; correct it before publication since the catalog is a permanent artifact.
  2. [Table 2, Sec. 4.2] The caption promises the 'best-fit RV semi-amplitude', but the table has no K column; include K and the false-alarm probability for the seven new tentative periods. Also, J085746.18+034255.3 is a WD+MS binary, so the abstract's '10 binary systems' should be qualified as 10 systems (9 DWDs).
  3. [Sec. 4.2] The three recovered periods are said to agree with published values 'within a few percent', but 1.69 h versus 1.5623 h is an 8% difference; suggest 'within ~10%' for this system.
  4. [Sec. 2] Typo: 'over 120,000 WD sub-exposures have been collected for 19,000 WDs and , and this is our parent sample'—stray 'and ,'.
  5. [Eq. (4), Fig. 9] The transformation to the < 4 AU parameter space depends on smoothing and on how f_bin > 1 points are discarded, as the authors note. The sentence 'they all overlap' should carry a caveat on how sensitive that overlap is to those choices.
  6. [Sec. 6.3, Abstract] '≤ 10 super-Chandrasekhar binaries' is the 3σ upper limit; the best-fit expectation is about 4. Distinguish expectation from upper limit in the abstract.

Circularity Check

0 steps flagged

No significant circularity: fbin and α are fitted forward-model parameters, not definitions of the data; the low-mass binary fraction is an external assumption explicitly flagged by the authors, and the self-citations are validated internally.

full rationale

The paper's central population claim is a forward-model fit: fbin,0.4 and α are adjusted so that simulated ΔRVmax histograms match the observed SDSS-V distribution (Sec. 5.1). The fitted parameters are not definitionally tied to the data they constrain; they enter through an assumed power-law separation function and a mock-observation pipeline. The low-mass WD binary fractions (100% below 0.25 M_sun, 70% for 0.25–0.45 M_sun) are external inputs taken from Brown et al. (2011) and Maoz & Hallakoun (2017). They are not derived from the paper's own target result, so this is a modeling assumption rather than a circular step. The authors explicitly acknowledge the conditional nature of their constraints: 'we do not place joint constraints' (Sec. 5.3), and Secs. 6.2–6.3 show that changing the low-mass WD fraction shifts the contours (Fig. 9). This is a robustness limitation, not a reduction of the claim to its input. The predicted numbers of super-Chandrasekhar and LISA-detectable binaries are projections from the same fitted simulation, so they are conditional model outputs rather than independent validations, but they are not used as evidence for the fit and are not equivalent by construction to the observed catalog. Self-citations (CORV from Arseneau et al. 2024, prior SDSS-V studies) are backed by in-paper validation, including the pair-subtraction RV-error check, and do not carry the population constraint. The method is also checked externally by reproducing the Badenes & Maoz (2012) contours in Fig. 6. No equation or fitted parameter is shown to equal its own input by definition.

Axiom & Free-Parameter Ledger

6 free parameters · 6 axioms · 0 invented entities

The population constraints rest on a forward model with multiple unverified inputs: a fixed low-mass WD binarity fraction, an adopted primary mass distribution from Kepler et al. (2019), a single power-law separation distribution, and an assumed circular-orbit geometry. The catalog itself requires fewer assumptions. These modeling choices are the main source of systematic uncertainty in the central population claim.

free parameters (6)
  • f_bin,0.4 = 0.09 (+0.03, -0.01)
    Binary fraction for WDs with primary mass >0.45 M_sun and separation <0.4 AU, fitted to the observed ΔRVmax distribution.
  • alpha = -0.62 ± 0.10
    Power-law index of the initial separation distribution n(a) ∝ a^α, fitted jointly with f_bin.
  • Low-mass WD binary fraction = 7.5% of all WDs
    Adopted from 100% binarity for M<0.25 M_sun and 70% for 0.25-0.45 M_sun (Brown et al. 2011; Maoz & Hallakoun 2017). The paper notes results are presented for this fraction; changing it to hot-WD-only gives 2.8%.
  • beta (mass ratio index) = 0
    Mass ratio distribution P(q) ∝ q^β; set to 0, stated to be insensitive to small changes.
  • amax = 0.4 AU
    Maximum binary separation probed; set by the 100 km/s ΔRVmax cutoff.
  • eta threshold = 3
    Selection threshold on RV variability parameter; chosen from simulated RV-error-only distribution to reduce false positives.
axioms (6)
  • domain assumption The current separation distribution of DWDs follows Eq. (2)-(3) from Maoz et al. (2012), derived from a constant formation rate and GW decay.
    Used to sample mock binary separations in Sec. 5.1.
  • domain assumption The primary WD mass distribution is that of Kepler et al. (2019) DA WDs, assumed representative of SDSS-V.
    Used to draw primary masses in the simulation; authors note mass distribution differences change results.
  • domain assumption Low-mass WDs (<0.45 M_sun) have enhanced binarity: 100% below 0.25 and 70% between 0.25-0.45 M_sun.
    Adopted from Brown et al. (2011) and Maoz & Hallakoun (2017); the paper does not fit this jointly.
  • domain assumption Orbits are circular and the photometric primary is the lower-mass WD (or random if neither is <0.35 M_sun).
    Assumed in computing orbital periods, RV semi-amplitudes, and selection effects in Sec. 5.1.
  • domain assumption The SDSS-V observation pattern and RV error distribution in the mock are drawn from the same WDs, making the simulation representative.
    Assumed to model the selection function; validated indirectly against Badenes & Maoz (2012).
  • domain assumption For the LISA estimate, the Milky Way WD population is a thin disk with scale height 300 pc, radius 20 kpc, and space density 4.39e-3 pc^-3 (Giammichele et al. 2012).
    Used to scale simulated binaries to Galactic LISA source counts in Sec. 6.4.

reviewed 2026-08-05 · how reviews work

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Cite this review

Pith. "Pith review of Double White Dwarf Binaries in SDSS-V DR19 : A catalog of DA white dwarf binaries and constraints on the binary population." pith.science (2026). https://pith.science/paper/WA5CBNWY

@misc{pith2026250902906,
  author       = {Pith},
  title        = {Pith review of: Double White Dwarf Binaries in SDSS-V DR19 : A catalog of DA white dwarf binaries and constraints on the binary population},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/WA5CBNWY}},
  note         = {Machine review of arXiv:2509.02906}
}
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read the original abstract

The fifth-generation Sloan Digital Sky Survey (SDSS-V) includes the first large-scale spectroscopic survey of white dwarfs (WDs) in the era of Gaia parallaxes. SDSS-V collects multiple exposures per target, making it ideal for binary detection. We present a search for hydrogen atmosphere (DA) double white dwarf (DWD) binaries in this rich dataset. We quantify radial velocity variations between sub-exposures to identify binary candidates, and also measure the orbital period for a subset of DWD binary candidates. We find 63 DWD binary candidates, of which 43 are new discoveries, and we provide tentative periods for 10 binary systems. Using these measurements, we place constraints on the binary fraction of the Galactic WD population with $< 0.4$ AU separations $f_{\mathrm{bin,0.4}} = 9\%$, and the power-law index of the initial separation distribution $\alpha = -0.62$. Using the simulated binary population, we estimate that $\leq 10$ super-Chandrasekhar binaries that merge within a Hubble time are expected in our sample. We predict that $\leq 5$ systems in our sample should be detectable via gravitational waves by LISA (Laser Interferometer Space Antenna), one of which has already been identified as a LISA verification source. We also estimate a total of about 10,000 - 20,000 LISA-detectable DWD binaries in the galaxy. Our catalog of WD+WD binary candidates in SDSS-V is now public, and promises to uncover a large number of exciting DWD systems.

Figures

Figures reproduced from arXiv: 2509.02906 by Axel D. Schwope, Boris T. G\"aensicke, Carles Badenes, Dmitry Bizyaev, Gagik Tovmasian, Gautham Adamane Pallathadka, J.J. Hermes, Kaike Pan, Kareem El-Badry, Nadia L. Zakamska, Nicola Pietro Gentile Fusillo, Nicole R. Crumpler, Priyanka Chakraborty, Scott F. Anderson, Sean Morrison, Sebastian Demasi, Stefan M. Arseneau, Tim Cunningham, Vedant Chandra, Yossef Zenati.

Figure 1
Figure 1. Figure 1: Distribution of median RV error, observational baseline, number of epochs, and median SNR per exposure for each WD is shown. to spectral noise and not physical motion, χ 2 m should follow a χ 2 distribution with (n − 1) degrees of free￾dom, where n is the number of sub-exposures. Using the measured value we estimate the false-alarm probability P(χ 2 > χ2 m). RV variability parameter η is then defined as η … view at source ↗
Figure 3
Figure 3. Figure 3: For different RV variability parameters η, the dis￾tribution of the number of WDs that show variability greater than η is shown. In red we show the theoretical expectation, and in black we show the observed distribution. Our sample shows larger variability than expected, indicating the pres￾ence of binaries. even wide binaries with relatively small RV variation, but makes it sensitive to WD binaries with i… view at source ↗
Figure 2
Figure 2. Figure 2: Top: Distribution of pair difference of RVs is shown for three different RV errors. Bottom: The compar￾ison of corrected CORV RV errors and RV errors estimated by pair subtraction is shown. We find that including the correction brings CORV RV errors to within 10% agreement with the fitted errors from pair-subtraction test. α, the power law index of binary separation distribution at the formation of DWDs (a… view at source ↗
Figure 4
Figure 4. Figure 4: Left: The Gaia color-magnitude diagram of our parent sample of WDs with hydrogen lines (blue) and DWD binary candidates (orange). We also show the cooling curves of 0.3 M⊙ and 0.6 M⊙ WD (B´edard et al. 2020). Middle: The mass distribution of the parent sample and the DWD binary candidates. Right: The temperature distribution of the parent sample and the DWD binary candidates. We use the mass and temperatur… view at source ↗
Figure 5
Figure 5. Figure 5: The results from the Lomb-Scargle periodogram period search for 10 WDs with large phase coverage in the RV curve. We show the best-fitting RV curve, along with the periodogram power. The best-fit period is chosen where the power is maximum [PITH_FULL_IMAGE:figures/full_fig_p009_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: The best-fit 1-σ (darker shade) and 2-σ (lighter shade) contours produced using the validation sample (G < 19 mag and RVerr < 55 km s−1 ) is compared the con￾tours from Badenes & Maoz (2012). Both contours are 1-σ smoothed using a Gaussian filter. The red dashed lines rep￾resent the expected number of super-Chandrasekhar mass binaries that can merge within the age of the universe. to be ≈ 2×10−12yr−1 , a f… view at source ↗
Figure 8
Figure 8. Figure 8: The results are presented for low-mass WD binary fraction of 7.5%. The constraints on fbin,0.4 and α are shown. The black dotted lines represent the DWD merger rate per year. The red dashed lines represent the number of super￾Chandrasekhar mass binaries that can merge within the age of the universe. 30% of the sample has been confirmed either be con￾firmed binaries or highly likely to be RV variables. This… view at source ↗
Figure 10
Figure 10. Figure 10: Predicted period and RV semi-amplitude for the Type-Ia progenitors (red) and for all DWDs (grey) in the simulated SDSS-V WD sample. The number of Type-Ia progenitors is exaggerated in the central plot to demonstrate the distribution of the sample. The histograms in bottom and left plot show the distribution of RV semi-amplitude K and the period P for Type-Ia progenitors. We find that a Type-Ia progenitors… view at source ↗
Figure 11
Figure 11. Figure 11: We show the expected number LISA detectable binaries in the first four year of its run. In green solid lines we show the predicted number of such binaries in our sample, and in black dotted lines we show the predicted number of such binaries in the galaxy. tion can significantly alter the DWD population which might explain the over abundance of LISA detectable DWD binaries they discover. A careful handlin… view at source ↗
Figure 12
Figure 12. Figure 12: Top: Region around Hα line of SDSS spectra are shown for the three mass transferring CV candidates. Bottom: Coadded SDSS spectra and available archival photometry is shown for the same three systems. The absolute flux of the coadded spectra are adjusted to match the photometry. In two of these systems we see a clear infrared excess in either the red end of SDSS spectrum or in infrared photometry, indicati… view at source ↗
Figure 13
Figure 13. Figure 13: Left: The power spectrum from Lomb-Scargle periodogram of the ZTF lightcurve of Gaia DR3 4319799701688937600. Right: The phase folded ZTF lightcurve is shown along with the best-fit sinusoidal model showing clear periodic variability [PITH_FULL_IMAGE:figures/full_fig_p021_13.png] view at source ↗

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Reference graph

Works this paper leans on

113 extracted references · 20 canonical work pages · 1 internal anchor

  1. [1]

    , " * write output.state after.block = add.period write newline

    ENTRY address archivePrefix author booktitle chapter doi edition editor eprint howpublished institution journal key month number organization pages publisher school series title misctitle type volume year version url label extra.label sort.label short.list INTEGERS output.state before.all mid.sentence after.sentence after.block FUNCTION init.state.consts ...

  2. [2]

    write newline

    " write newline "" before.all 'output.state := FUNCTION format.url url empty "" new.block "" url * "" * if FUNCTION format.eprint eprint empty "" archivePrefix empty "" archivePrefix "arXiv" = new.block " " eprint * " " * new.block " " eprint * " " * if if if FUNCTION format.doi doi empty "" " " doi * " " * if FUNCTION format.pid doi empty eprint empty ur...

  3. [3]

    E )׆gtr =N

    thebibliography [1] 20pt to REFERENCES 6pt =0pt -12pt 10pt plus 3pt =0pt =0pt =1pt plus 1pt =0pt =0pt -12pt =13pt plus 1pt =20pt =13pt plus 1pt \@M =10000 =-1.0em =0pt =0pt 0pt =0pt =1.0em @enumiv\@empty 10000 10000 `\.\@m \@noitemerr \@latex@warning Empty `thebibliography' environment \@ifnextchar \@reference \@latexerr Missing key on reference command E...

  4. [4]

    2022, The Astrophysical Journal Supplement Series, 259, 35, 10.3847/1538-4365/ac4414

    Abdurro'uf , Accetta, K., Aerts, C., et al. 2022, The Astrophysical Journal Supplement Series, 259, 35, 10.3847/1538-4365/ac4414

  5. [5]

    L., et al

    Adamane Pallathadka, G., Chandra, V., Zakamska, N. L., et al. 2024, The Astrophysical Journal, 968, 42, 10.3847/1538-4357/ad3e86

  6. [6]

    Double White Dwarf Binaries in SDSS-V DR19 : The discovery of a rare DA+DQ white dwarf binary with 31 hour orbital period

    Adamane Pallathadka, G., Chandra, V., Gansicke, B. T., et al. 2025, Double White Dwarf Binaries in SDSS - V DR19 : The discovery of a rare DA + DQ white dwarf binary with 31 hour orbital period, arXiv, 10.48550/arXiv.2507.11618

  7. [7]

    F., Argudo-Fernández, M., et al

    Almeida, A., Anderson, S. F., Argudo-Fernández, M., et al. 2023, The Astrophysical Journal Supplement Series, 267, 44, 10.3847/1538-4365/acda98

  8. [8]

    2024, The Astrophysical Journal, 963, 17, 10.3847/1538-4357/ad2168

    Arseneau, S., Chandra, V., Hwang, H.-C., et al. 2024, The Astrophysical Journal, 963, 17, 10.3847/1538-4357/ad2168

  9. [9]

    P., Tollerud, E

    Astropy Collaboration , Robitaille, T. P., Tollerud, E. J., et al. 2013, Astronomy and Astrophysics, 558, A33, 10.1051/0004-6361/201322068

  10. [10]

    M., Sipőcz, B

    Astropy Collaboration , Price-Whelan, A. M., Sipőcz, B. M., et al. 2018, The Astronomical Journal, 156, 123, 10.3847/1538-3881/aabc4f

  11. [11]

    M., Lim, P

    Astropy Collaboration , Price-Whelan, A. M., Lim, P. L., et al. 2022, The Astrophysical Journal, 935, 167, 10.3847/1538-4357/ac7c74

  12. [12]

    2012, The Astrophysical Journal, 749, L11, 10.1088/2041-8205/749/1/L11

    Badenes, C., & Maoz, D. 2012, The Astrophysical Journal, 749, L11, 10.1088/2041-8205/749/1/L11

  13. [13]

    E., & Lupton, R

    Badenes, C., Mullally, F., Thompson, S. E., & Lupton, R. H. 2009, The Astrophysical Journal, 707, 971, 10.1088/0004-637X/707/2/971

  14. [14]

    C., Kulkarni, S

    Bellm, E. C., Kulkarni, S. R., Graham, M. J., et al. 2019, Publications of the Astronomical Society of the Pacific, 131, 018002, 10.1088/1538-3873/aaecbe

  15. [15]

    S., & Vaughan, A

    Bowen, I. S., & Vaughan, A. H. 1973, Applied Optics, 12, 1430, 10.1364/AO.12.001430

  16. [16]

    R., et al

    Breedt, E., Steeghs, D., Marsh, T. R., et al. 2017, Monthly Notices of the Royal Astronomical Society, 468, 2910, 10.1093/mnras/stx430

  17. [17]

    M., Kilic, M., Brown, W

    Brown, J. M., Kilic, M., Brown, W. R., & Kenyon, S. J. 2011, The Astrophysical Journal, 730, 67, 10.1088/0004-637X/730/2/67

  18. [18]

    R., Kilic, M., Allende Prieto, C., Gianninas, A., & Kenyon, S

    Brown, W. R., Kilic, M., Allende Prieto, C., Gianninas, A., & Kenyon, S. J. 2013, The Astrophysical Journal, 769, 66, 10.1088/0004-637X/769/1/66

  19. [19]

    R., Kilic, M., Kenyon, S

    Brown, W. R., Kilic, M., Kenyon, S. J., & Gianninas, A. 2016, The Astrophysical Journal, 824, 46, 10.3847/0004-637X/824/1/46

  20. [20]

    R., Kilic, M., Prieto, C

    Brown, W. R., Kilic, M., Prieto, C. A., & Kenyon, S. J. 2010, The Astrophysical Journal, 723, 1072, 10.1088/0004-637X/723/2/1072

  21. [21]

    R., Kilic, M., Kosakowski, A., et al

    Brown, W. R., Kilic, M., Kosakowski, A., et al. 2020, The Astrophysical Journal, 889, 49, 10.3847/1538-4357/ab63cd

  22. [22]

    B., Coughlin, M

    Burdge, K. B., Coughlin, M. W., Fuller, J., et al. 2020, The Astrophysical Journal Letters, 905, L7, 10.3847/2041-8213/abca91

  23. [23]

    2020, The Astrophysical Journal, 901, 93, 10.3847/1538-4357/abafbe

    Bédard, A., Bergeron, P., Brassard, P., & Fontaine, G. 2020, The Astrophysical Journal, 901, 93, 10.3847/1538-4357/abafbe

  24. [24]

    C., Magnier, E

    Chambers, K. C., Magnier, E. A., Metcalfe, N., et al. 2016, The Pan - STARRS1 Surveys , arXiv, 10.48550/arXiv.1612.05560

  25. [25]

    L., & Budavári, T

    Chandra, V., Hwang, H.-C., Zakamska, N. L., & Budavári, T. 2020, Monthly Notices of the Royal Astronomical Society, 497, 2688, 10.1093/mnras/staa2165

  26. [26]

    L., et al

    Chandra, V., Hwang, H.-C., Zakamska, N. L., et al. 2021, The Astrophysical Journal, 921, 160, 10.3847/1538-4357/ac2145

  27. [27]

    1931, The Astrophysical Journal, 74, 81, 10.1086/143324

    Chandrasekhar, S. 1931, The Astrophysical Journal, 74, 81, 10.1086/143324

  28. [28]

    T., Burdge, K

    Chickles, E. T., Burdge, K. B., Chakraborty, J., et al. 2025, The Astrophysical Journal, 987, 206, 10.3847/1538-4357/add34c

  29. [29]

    R., Chandra, V., Zakamska, N

    Crumpler, N. R., Chandra, V., Zakamska, N. L., et al. 2024, The Astrophysical Journal, 977, 237, 10.3847/1538-4357/ad8ddc

  30. [30]

    2025, The Astrophysical Journal, 989, 24, 10.3847/1538-4357/ade9a9

    ---. 2025, The Astrophysical Journal, 989, 24, 10.3847/1538-4357/ade9a9

  31. [31]

    2022, Astronomy & Astrophysics, 662, A40, 10.1051/0004-6361/202243337

    Culpan, R., Geier, S., Reindl, N., et al. 2022, Astronomy & Astrophysics, 662, A40, 10.1051/0004-6361/202243337

  32. [32]

    D., Baxter, R., Külebi, B., et al

    Dobbie, P. D., Baxter, R., Külebi, B., et al. 2012, Monthly Notices of the Royal Astronomical Society, 421, 202, 10.1111/j.1365-2966.2012.20291.x

  33. [33]

    P., & Marsh, T

    Geier, S., Raddi, R., Gentile Fusillo, N. P., & Marsh, T. R. 2019, Astronomy & Astrophysics, 621, A38, 10.1051/0004-6361/201834236

  34. [34]

    H., Nemeth, P., et al

    Geier, S., Østensen, R. H., Nemeth, P., et al. 2017, Astronomy and Astrophysics, 600, A50, 10.1051/0004-6361/201630135

  35. [35]

    P., Tremblay, P

    Gentile Fusillo, N. P., Tremblay, P. E., Cukanovaite, E., et al. 2021, Monthly Notices of the Royal Astronomical Society, 508, 3877, 10.1093/mnras/stab2672

  36. [36]

    P., Tremblay, P.-E., Gänsicke, B

    Gentile Fusillo, N. P., Tremblay, P.-E., Gänsicke, B. T., et al. 2019, Monthly Notices of the Royal Astronomical Society, 482, 4570, 10.1093/mnras/sty3016

  37. [37]

    2012, The Astrophysical Journal Supplement Series, 199, 29, 10.1088/0067-0049/199/2/29

    Giammichele, N., Bergeron, P., & Dufour, P. 2012, The Astrophysical Journal Supplement Series, 199, 29, 10.1088/0067-0049/199/2/29

  38. [38]

    M., Brasseur, C

    Ginsburg, A., Sipőcz, B. M., Brasseur, C. E., et al. 2019, The Astronomical Journal, 157, 98, 10.3847/1538-3881/aafc33

  39. [39]

    E., Siegmund, W

    Gunn, J. E., Siegmund, W. A., Mannery, E. J., et al. 2006, The Astronomical Journal, 131, 2332, 10.1086/500975

  40. [40]

    T., Marsh, T

    Gänsicke, B. T., Marsh, T. R., & Southworth, J. 2007, Monthly Notices of the Royal Astronomical Society, 380, L35, 10.1111/j.1745-3933.2007.00343.x

  41. [41]

    R., Millman, K

    Harris, C. R., Millman, K. J., Van Der Walt, S. J., et al. 2020, Nature, 585, 357, 10.1038/s41586-020-2649-2

  42. [42]

    2016, Publications of the Astronomical Society of the Pacific, 128, 082001, 10.1088/1538-3873/128/966/082001

    Heber, U. 2016, Publications of the Astronomical Society of the Pacific, 128, 082001, 10.1088/1538-3873/128/966/082001

  43. [43]

    M., Hermes, J

    Heintz, T. M., Hermes, J. J., El-Badry, K., et al. 2022, The Astrophysical Journal, 934, 148, 10.3847/1538-4357/ac78d9

  44. [44]

    Hunter, J. D. 2007, Computing in Science & Engineering, 9, 90, 10.1109/MCSE.2007.55

  45. [45]

    T., Breedt, E., et al

    Inight, K., Gänsicke, B. T., Breedt, E., et al. 2021, Monthly Notices of the Royal Astronomical Society, 504, 2420, 10.1093/mnras/stab753

  46. [46]

    2020, Common envelope evolution, version: 20201201 edn., AAS - IOP astronomy

    Ivanova, N., Justham, S., & Ricker, P. 2020, Common envelope evolution, version: 20201201 edn., AAS - IOP astronomy. [2021 collection] (Bristol, UK: IOP Publishing), 10.1088/2514-3433/abb6f0

  47. [47]

    O., Pelisoli, I., Jordan, S., et al

    Kepler, S. O., Pelisoli, I., Jordan, S., et al. 2013, Monthly Notices of the Royal Astronomical Society, 429, 2934, 10.1093/mnras/sts522

  48. [48]

    O., Pelisoli, I., Koester, D., et al

    Kepler, S. O., Pelisoli, I., Koester, D., et al. 2019, Monthly Notices of the Royal Astronomical Society, 486, 2169, 10.1093/mnras/stz960

  49. [49]

    2020, The Astrophysical Journal, 898, 84, 10.3847/1538-4357/ab9b8d

    Kilic, M., Bergeron, P., Kosakowski, A., et al. 2020, The Astrophysical Journal, 898, 84, 10.3847/1538-4357/ab9b8d

  50. [50]

    R., Allende Prieto, C., et al

    Kilic, M., Brown, W. R., Allende Prieto, C., et al. 2012, The Astrophysical Journal, 751, 141, 10.1088/0004-637X/751/2/141

  51. [51]

    R., Heinke, C

    Kilic, M., Brown, W. R., Heinke, C. O., et al. 2016, Monthly Notices of the Royal Astronomical Society, 460, 4176, 10.1093/mnras/stw1277

  52. [52]

    2021, Monthly Notices of the Royal Astronomical Society, 502, 4972, 10.1093/mnras/stab439

    Kilic, M., Bédard, A., & Bergeron, P. 2021, Monthly Notices of the Royal Astronomical Society, 502, 4972, 10.1093/mnras/stab439

  53. [53]

    J., Gianninas, A., et al

    Kilic, M., Hermes, J. J., Gianninas, A., et al. 2013, Monthly Notices of the Royal Astronomical Society: Letters, 438, L26, 10.1093/mnrasl/slt151

  54. [54]

    A., Rix, H.-W., Aerts, C., et al

    Kollmeier, J. A., Rix, H.-W., Aerts, C., et al. 2025, Sloan Digital Sky Survey - V : Pioneering Panoptic Spectroscopy , arXiv, 10.48550/arXiv.2507.06989

  55. [55]

    2022, Monthly Notices of the Royal Astronomical Society, 511, 5936, 10.1093/mnras/stac415

    Korol, V., Hallakoun, N., Toonen, S., & Karnesis, N. 2022, Monthly Notices of the Royal Astronomical Society, 511, 5936, 10.1093/mnras/stac415

  56. [56]

    R., et al

    Kosakowski, A., Dorsch, M., Brown, W. R., et al. 2025, The Astrophysical Journal, 987, 205, 10.3847/1538-4357/add1cf

  57. [57]

    2018, Monthly Notices of the Royal Astronomical Society, 480, 302, 10.1093/mnras/sty1545

    Kupfer, T., Korol, V., Shah, S., et al. 2018, Monthly Notices of the Royal Astronomical Society, 480, 302, 10.1093/mnras/sty1545

  58. [58]

    B., et al

    Lamberts, A., Blunt, S., Littenberg, T. B., et al. 2019, Monthly Notices of the Royal Astronomical Society, 490, 5888, 10.1093/mnras/stz2834

  59. [59]

    2019, The Astrophysical Journal, 871, 148, 10.3847/1538-4357/aaf9a1

    Li, Z., Chen, X., Chen, H.-L., & Han, Z. 2019, The Astrophysical Journal, 871, 148, 10.3847/1538-4357/aaf9a1

  60. [60]

    2020, The Astrophysical Journal, 893, 2, 10.3847/1538-4357/ab7dc2

    Li, Z., Chen, X., Chen, H.-L., et al. 2020, The Astrophysical Journal, 893, 2, 10.3847/1538-4357/ab7dc2

  61. [61]

    L., & Thorstensen, J

    Liu, Y., Hwang, H.-C., Zakamska, N. L., & Thorstensen, J. R. 2023, Monthly Notices of the Royal Astronomical Society, 522, 2719, 10.1093/mnras/stad1156

  62. [62]

    Lomb, N. R. 1976, Astrophysics and Space Science, 39, 447, 10.1007/BF00648343

  63. [63]

    Maoz, D., Badenes, C., & Bickerton, S. J. 2012, The Astrophysical Journal, 751, 143, 10.1088/0004-637X/751/2/143

  64. [64]

    2017, Monthly Notices of the Royal Astronomical Society, 467, 1414, 10.1093/mnras/stx102

    Maoz, D., & Hallakoun, N. 2017, Monthly Notices of the Royal Astronomical Society, 467, 1414, 10.1093/mnras/stx102

  65. [65]

    2018, Monthly Notices of the Royal Astronomical Society, 476, 2584, 10.1093/mnras/sty339

    Maoz, D., Hallakoun, N., & Badenes, C. 2018, Monthly Notices of the Royal Astronomical Society, 476, 2584, 10.1093/mnras/sty339

  66. [66]

    2012, Publications of the Astronomical Society of Australia, 29, 447, 10.1071/AS11052

    Maoz, D., & Mannucci, F. 2012, Publications of the Astronomical Society of Australia, 29, 447, 10.1071/AS11052

  67. [67]

    2014, Annual Review of Astronomy and Astrophysics, 52, 107, 10.1146/annurev-astro-082812-141031

    Maoz, D., Mannucci, F., & Nelemans, G. 2014, Annual Review of Astronomy and Astrophysics, 52, 107, 10.1146/annurev-astro-082812-141031

  68. [68]

    Marocco, F., Eisenhardt, P. R. M., Fowler, J. W., et al. 2020, CatWISE2020 Catalog , IPAC, 10.26131/IRSA551

  69. [69]

    2021, The Astrophysical Journal Supplement Series, 253, 8, 10.3847/1538-4365/abd805

    ---. 2021, The Astrophysical Journal Supplement Series, 253, 8, 10.3847/1538-4365/abd805

  70. [70]

    Marsh, T. R. 2011, Classical and Quantum Gravity, 28, 094019, 10.1088/0264-9381/28/9/094019

  71. [71]

    R., Nelemans, G., & Steeghs, D

    Marsh, T. R., Nelemans, G., & Steeghs, D. 2004, Monthly Notices of the Royal Astronomical Society, 350, 113, 10.1111/j.1365-2966.2004.07564.x

  72. [72]

    C., Fanson, J., Schiminovich, D., et al

    Martin, D. C., Fanson, J., Schiminovich, D., et al. 2005, The Astrophysical Journal, 619, L1, 10.1086/426387

  73. [73]

    Maxted, P. F. L., Marsh, T. R., & Moran, C. K. J. 2002 a , Monthly Notices of the Royal Astronomical Society, 332, 745, 10.1046/j.1365-8711.2002.05368.x

  74. [74]

    2002 b , Monthly Notices of the Royal Astronomical Society, 319, 305, 10.1046/j.1365-8711.2000.03840.x

    ---. 2002 b , Monthly Notices of the Royal Astronomical Society, 319, 305, 10.1046/j.1365-8711.2000.03840.x

  75. [75]

    E., et al

    Munday, J., Pelisoli, I., Tremblay, P. E., et al. 2024, Monthly Notices of the Royal Astronomical Society, 532, 2534, 10.1093/mnras/stae1645

  76. [76]

    2025, Nature Astronomy, 9, 872, 10.1038/s41550-025-02528-4

    Munday, J., Pakmor, R., Pelisoli, I., et al. 2025, Nature Astronomy, 9, 872, 10.1038/s41550-025-02528-4

  77. [77]

    2002, Astronomy & Astrophysics, 386, 957, 10.1051/0004-6361:20020361

    Napiwotzki, R., Koester, D., Nelemans, G., et al. 2002, Astronomy & Astrophysics, 386, 957, 10.1051/0004-6361:20020361

  78. [78]

    A., Lisker, T., et al

    Napiwotzki, R., Karl, C. A., Lisker, T., et al. 2020, Astronomy & Astrophysics, 638, A131, 10.1051/0004-6361/201629648

  79. [79]

    F., Verbunt, F., & Yungelson, L

    Nelemans, G., Portegies Zwart, S. F., Verbunt, F., & Yungelson, L. R. 2001 a , Astronomy and Astrophysics, 368, 939, 10.1051/0004-6361:20010049

  80. [80]

    R., & Portegies Zwart, S

    Nelemans, G., Verbunt, F., Yungelson, L. R., & Portegies Zwart, S. F. 2000, Astronomy and Astrophysics, 360, 1011, 10.48550/arXiv.astro-ph/0006216

Showing first 80 references.

This paper was first reviewed by deepseek-v4-flash on August 5, 2026.