CoChat
Sign Up
Cited by 29Stellar, planetary, and galactic studiesAstro and Planetary ScienceAstronomy and Astrophysical Research

Analysis of 1SWASP J140747.93−394542.6 eclipse fine-structure: hints of exomoons

Open access
van Werkhoven, T. I. M., Kenworthy, M. A., Mamajek, E. E.·2014·Monthly Notices of the Royal Astronomical Society
DOI 10.1093/mnras/stu725
Open this paper in CoChat — free accountOpen PDF

Abstract

A recently discovered V = 12.3 mag K5 pre-main-sequence star in the SuperWASP (Super Wide Angle Search for Planets) data base shows a peculiar light curve with a highly structured eclipse pattern covering a timespan of at least 54 d with maximum dimming of at least 3.3 mag. The central eclipse is surrounded by two 1 mag eclipses at ±12 and ±26 d. The authors speculate that the star is eclipsed by a substellar companion with an extended and highly structured ring system. To investigate the nightly light-curve structure and to confirm the multiple-ring hypothesis, we have carried out a calibrated reduction of the SuperWASP data, removing both systematic errors and periodic stellar variability. We count at least 24 inflection points on ingress and 16 on egress, consistent with the presence of at least 24 rings in this disc. By measuring the light-curve slope, we find implied speeds for the eclipsing object that are incompatible with a closed Kepler orbit with P = 2.3 yr. We propose several scenarios that could give rise to such light-curve slopes and find that azimuthal ring structure (analogous to ‘spokes’ seen in Saturn's rings) can account for the observed light curve. The highly structured ring system also implies the presence of exomoons orbiting the secondary companion.

Integrity signals

Registry

Crossref · 10.1093/mnras/stu725

Cites

38 of 38 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

23 of 30 cited sources checked · 13 supported · 0 flagged · accuracy not yet measured

  • Premisecitation

    The multiple CCDs of SuperWASP provide significantly different light curves for J1407.

    “The multiple CCDs of SuperWASP provide significantly different light curves, as observed by Mamajek et al. (2012) and Norton et al. (2011).”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites Mamajek et al. (2012) source

      The Figure 8 caption reports that J1407’s SuperWASP photometry sometimes jumps between two levels by tenths of a magnitude. It does not attribute those differences to multiple CCDs or compare light curves from individual CCDs, so the claimed explanation is unsupported. (LLM, conf=0.78)

      Experimental — accuracy not yet measured
    • cites Norton et al. (2011) source

      Section 2 (p. 2) says SuperWASP light curves were analysed separately for each camera to minimise systematic differences between cameras. That supports the general point in the citing sentence, but the passage does not report significantly different light curves for J1407 specifically. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
  • Findingnone given

    The most significant change to the adopted parameters for J1407 is that the estimated radius is about 18 per cent larger compared to Mamajek et al. (2012).

    “In summary, the most significant change to the adopted parameters for J1407 is that the estimate radius is about 18 per cent larger compared to Mamajek et al. (2012).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Mamajek et al. (2012) source
  • Interpretationreasoning

    The ratio of the variability timescale of an hour to half the 54 d eclipse duration implies a disc aspect ratio h/r ≈ 0.0015.

    “This ratio of the variability time-scale of an hour over half the eclipse duration of 54 d implies an aspect ratio of the disc of h/r ≈ 0.0015, confirming earlier findings by Mamajek et al. (2012).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Mamajek et al. (2012) source

      Section 3.7 uses the ratio of short-term eclipse variability to half the eclipse duration to estimate the disk’s aspect ratio, and gives the eclipse duration as approximately 54 days. But it uses a few hours (or a quarter day), not one hour, and estimates h/r ≈ 0.01 rather than 0.0015. The cited paper therefore supports the method, not the claimed numerical finding. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
  • Premisecitation

    The central eclipse of J1407 is surrounded by two 1 mag eclipses at ±12 and ±26 d.

    “The central eclipse is surrounded by two 1 mag eclipses at ±12 and ±26 d.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Mamajek et al. (2012) source

      Section 3.3 and the Figure 5 caption describe two pairs of dips centered around the main eclipse, separated by about 24 and 51.5 days—consistent with dips at approximately ±12 and ±26 days. Those passages do not give the peripheral dips’ depth as 1 mag, so that part of the claim is not established by the eligible passages. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
  • Interpretationreasoning

    Minimum speeds derived from light-curve slopes, stellar radius and limb darkening are incompatible with the minimum period of 2.3 yr found by Mamajek et al. (2012), despite large uncertainties on stellar properties.

    “The minimum speeds derived only from the light-curve slopes, stellar radius and limb darkening are incompatible with both the minimum period of 2.3 yr found by Mamajek et al. (2012), in spite of the large uncertainties on stellar properties.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Mamajek et al. (2012) source
  • Classified as probably not a substantial claim. 10
  • May combine two claims. 29

  • Classified as probably not a substantial claim.

    Premisecitation

    The scenario proposed by Mamajek et al. (2012) involves a circumsecondary or circumplanetary disc that obscures the primary star J1407.

    “The scenario Mamajek et al. (2012) propose involves a circumsecondary or circumplanetary disc, which obscures the primary star, J1407.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Mamajek et al. (2012) source

  • May combine two claims.

    Premisecitation

    The adopted age for J1407 is the mean UCL age from Pecaut et al. (2012) of ~16 Myr, but an age in the range ~5-20 Myr is possible.

    “We continue to adopt the mean UCL age from Pecaut et al. (2012, , ∼16 Myr) as representative for J1407, but note that an age somewhere in the range of ∼5-20 Myr is possible.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Pecaut et al. (2012) source

  • May combine two claims.

    Premisecitation

    J1407's light curve shows a highly structured eclipse pattern covering at least 54 d with maximum dimming of at least 3.3 mag.

    “A recently discovered V = 12.3 mag K5 pre-main-sequence star in the SuperWASP (Super Wide Angle Search for Planets) data base shows a peculiar light curve with a highly structured eclipse pattern covering a timespan of at least 54 d with maximum dimming of at least 3.3 mag.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Mamajek et al. (2012) source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Forward scattering is seen and modelled in Fomalhaut's debris disc and in the light curve of disintegrating exoplanet KIC 12557548 b.

    “Such forward scattering is seen and modelled in Fomalhaut's debris disc (Kalas, Graham & Clampin 2005) and in the light curve produced by a disintegrating exoplanet KIC 12557548 b (Brogi et al. 2012;Rappaport et al. 2012).”
    Quote in the paperNot a substantial claim2 of 3 sources checked
    • cites Kalas, Graham & Clampin 2005 source
    • cites Brogi et al. 2012 source
    • cites Rappaport et al. 2012 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Equation 14 is equivalent to equation 10 in Mamajek et al. (2012), although the authors missed a factor π in their equation.

    “Equation ( 14) is equivalent to equation 10 in Mamajek et al. (2012), although the authors missed a factor π in their equation.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Mamajek et al. (2012) source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Mamajek et al. (2012) propose a preliminary 4-ring model with a central opaque disc and three discrete rings with opacities τ = 0.5, 0.2, 0.05.

    “They propose a preliminary 4-ring model with a central opaque disc accompanied by three discrete rings with opacities τ = 0.5, 0.2, 0.05.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Mamajek et al. (2012) source

      The Figure 12 caption and Table 5 give optical depths of 0.5 for the inner disk and 0.2 and 0.05 for two rings. Section 3.7 says a third, outer ring (τ⊥ ≈ 0.09) is needed but is not included in that preliminary model. The claim treats the 0.5 value as a ring opacity and describes the disk as opaque, neither of which matches the model as stated. (LLM, conf=0.91)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Based on the absence of a second eclipse, Mamajek et al. (2012) constrain the period P > 2.33 yr, yielding an orbital radius greater than 17 au and a circular orbital velocity less than 21.7 km/s (assuming m1 = 0.9 M_sun).

    “Based on the absence of a second eclipse, the authors constrain the period P > 2.33 yr, yielding an orbital radius greater than 17 au and a circular orbital velocity less than 21.7 km s -foot_1 (assuming m 1 = 0.9 M ).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Mamajek et al. (2012) source

      Section 3.5 finds no additional deep eclipse at periods up to 850 days, supporting the period constraint. Section 3.7 gives P > 2.33 yr and, assuming a primary mass of 0.9 solar masses, an orbital velocity <21.7 km/s. It gives the orbital-radius bound as >1.7 AU, not >17 AU. (LLM, conf=0.95)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Findingown data

    The first high-speed night is compatible with the 21.7 km/s upper limit of Mamajek et al. (2012), but the second is not.

    “While the first night is compatible with the 21.7 km s -1 upper limit found by Mamajek et al. (2012), the second night is not.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Mamajek et al. (2012) source

  • May combine two claims.

    Findingcitation

    Using revised intrinsic colours and BVJHKs photometry, the star is statistically consistent with being unreddened, but extinction A_J = 0.02 ± 0.02 (A_V = 0.06 ± 0.06 mag) is adopted.

    “Using the revised intrinsic colours for K5 pre-MS stars, and the BVJHK s photometry for J1407 compiled inMamajek et al. (2012), we estimate that the star is statistically consistent with being unreddened, but adopt extinction A J = 0.02 ± 0.02 (A V = 0.06 ± 0.06 mag).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Mamajek et al. (2012) source

      Section 3.1, Table 3 compiles V, J, H, and Ks photometry for J1407, but does not list a B-band measurement. The citing authors present the unreddened assessment and extinction values as their own estimates, not as results attributed to Mamajek et al. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

  • Classified as probably not a substantial claim.

    Premisecitation

    Mamajek et al. (2012) found a 21.7 km/s upper limit.

    “While the first night is compatible with the 21.7 km s -1 upper limit found by Mamajek et al. (2012), the second night is not.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Mamajek et al. (2012) source

  • Classified as probably not a substantial claim.

    Premisecitation

    Mamajek et al. (2012) found a minimum period of 2.3 yr.

    “The minimum speeds derived only from the light-curve slopes, stellar radius and limb darkening are incompatible with both the minimum period of 2.3 yr found by Mamajek et al. (2012), in spite of the large uncertainties on stellar properties.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Mamajek et al. (2012) source

  • May combine two claims.

    Findingcitation

    Adopting the spectral type K5±1 and intrinsic properties of K5 pre-MS stars, the revised stellar parameters are T_eff = 4140 +190-120 K and BC_J = 1.58 ± 0.06 mag.

    “Adopting the spectral type of K5±1 from Mamajek et al. (2012), and the intrinsic properties of K5 pre-MS stars from Pecaut & Mamajek (2013), we estimate slightly revised stellar parameters: T eff = 4140 +190-120 K and BC J 1.58 ± 0.06 mag.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites Mamajek et al. (2012) source
    • cites Pecaut & Mamajek (2013) source

  • May combine two claims.

    Findingown data

    The adopted mass of J1407 is 0.9 ± 0.1 M_sun based on its HR diagram position, with four of five sets of pre-MS evolutionary tracks bracketing ~0.9 M_sun.

    “We adopt a mass of 0.9 ± 0.1 M based on the HR diagram position of J1407, noting that four of the five sets of pre-MS evolutionary tracks lead to inferred masses closely bracketing ∼0.9 M .”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    Removing the stellar variability further improves the photometry.

    “Removing the stellar variability further improves the photometry.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Ingress and egress of the J1407 eclipse show a similar trend of linearly decreasing opacity away from the eclipse mid-point, but the nightly structure is very different from night to night.

    “Ingress and egress show a similar trend of linearly decreasing opacity away from the eclipse mid-point, but the nightly structure is very different from night to night.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingreasoning

    The cooler T_eff moved J1407 from the radiative track to the Hayashi track and produced younger isochronal ages of ~10 ± 3 Myr.

    “however, the cooler T eff has moved the star from the radiative track to the Hayashi track, and produced correspondingly younger isochronal ages (∼10 ± 3 Myr).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The de-correlated, de-trended J1407 light curve has at least 24 inflection points on ingress and 16 on egress.

    “Furthermore, we find a myriad of fine structures in the light curve, with at least 24 inflection points on ingress, and 16 on egress (see Table 4 and Fig. 8)”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Some inflection points are directly observed in the nightly data, while others are implied by a mismatch in photometric observations between consecutive observation windows, implying an unseen change in light-curve slope.

    “Some inflection points are directly observed in the nightly data, whilst others are implied by a mismatch in photometric observations between consecutive observation windows, implying an unseen change in light-curve slope.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Most nights have occultation speeds below 15 km/s, but two nights during ingress have exceptionally high speeds.

    “Most nights have <15 km s -1 occultation speeds, but two nights during ingress have exceptionally high speeds.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The two exceptionally high ingress slopes are 1.7 and 3.0 L d^-1, corresponding to 22(3) km/s and 38(5) km/s, respectively.

    “These slopes are 1.7 and 3.0 L d -1 , which correspond to 22(3) km s -1 to 38(5) km s -1 , respectively.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The data show a periodicity of approximately 3.2 d for the different observation seasons, with significant differences between seasons.

    “We find a periodicity of approximately 3.2 d for the different observation seasons, with significant differences between the seasons.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The eclipse lasts at least 54 d with roughly symmetrical ingress and egress but asymmetry in the nightly variation.

    “The eclipse mid-point is at approximately MHJD 54 222 and lasts at least 54 d with roughly symmetrical ingress and egress but asymmetry in the nightly variation.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    An ellipsoidal orbit would allow larger periastron speeds and explain the anomalous velocities, but these are not fast enough to explain the observations.

    “An ellipsoidal orbit would allow for larger periastron speeds and explain the anomalous velocities implied in the data; however, these are not fast enough to explain the observations.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductown data

    The SuperWASP photometric flux data for J1407 were reduced using an ensemble of photometrically quiet nearby reference stars to remove systematic effects and de-trended for stellar variability, showing improvement over raw flux and pipeline outputs.

    “We have reduced the SuperWASP extracted photometric flux data for J1407 using an ensemble of photometrically quiet nearby reference stars to remove systematic effect in the data, and de-trended for stellar variability, showing an improvement over the raw flux as well as the automatically reduced flux pipeline outputs.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    The fine structure in the J1407 light curve is not due to randomly occurring systematic effects but is due to J1407.

    “By de-correlating against reference stars, we ensure these are not randomly occurring systematic effects, but are due to J1407.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    For a disc alone, the structure would be radially smeared out by internal disc interactions on short dynamical timescales; therefore the structure is indicative of shepherding exomoons.

    “Given that for a disc alone, this structure would be radially smeared out by internal disc interactions on short dynamical time-scales, this is indicative of the presence of shepherding exomoons.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Assuming m2 = 50 M_J and P = 3.5 yr, the planet's orbital speed is 19 km/s and the ring distance is 0.15 au.

    “Assuming m 2 = 50 M J and P = 3.5 yr, this would give an orbital speed of the planet of v ring = 19 km s -1 such that the ring distance would be at 19 km s -1 × 14 d = 0.15 au.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    A disc orbiting J1407 obscuring the star light due to relative motion would yield a one-time eclipsing event, but is disregarded because it requires a very thin disc and does not explain the symmetric dimming around the central minimum.

    “A disc orbiting J1407 obscuring the star light due to the relative motion between us and J1407 would yield a one-time eclipsing event, but is disregarded because it requires a very thin disc (aspect ratio height over radius ∼10 -8 ) and it does not explain the symmetric dimming around the central minimum.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    For that radius, the ring rotates at 17 km/s, and the total occulting speed of 36 km/s is compatible with the observations.

    “For this radius, the ring would rotate at a speed of v clump = 17 km s -1 , which in total would yield a occulting speed of 36 km s -1 , compatible with the observations.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    The observed slope could be a combination of the slope from a ring eclipsing edge plus an additional slope due to forward scattering from particles in the ring wall.

    “A third option is that the observed slope is a combination of the slope from a ring eclipsing edge added with an additional slope due to forward scattering from the particles making up the ring wall.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Radial structures ('spokes') have been observed in the B-rings of Saturn.

    “Such radial structures ('spokes') have been observed in the B-rings of Saturn (Smith et al. 1982).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Smith et al. 1982 source

  • May combine two claims.

    Interpretationnone given

    Each inflection point in the J1407 light curve indicates a change in slope, which implies a change in opacity, and thus a new ring beginning to eclipse the star.

    “Each inflection point indicates a change in slope, which in turn implies change in opacity, and thus a new ring beginning to eclipse the star.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductown data

    The raw flux shows an offset between CCDs and significant scatter (ρ = 0.49), while automatically reduced flux is more consistent but still shows large spread (ρ = 0.54).

    “The raw flux (FLUX) shows an offset between the CCDs as well as a significant scatter (Pearson's correlation coefficient ρ = 0.49), while the automatically reduced flux (TAMFLUX) is more consistent between different CCDs but still shows a large spread between the data (ρ = 0.54).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductown data

    The manually de-correlated flux shows no offset and significantly reduced scatter between the three CCDs (ρ = 0.81).

    “The manually de-correlated flux shows no offset and significantly reduced scatter, indicating consistency between the three different CCDs (ρ = 0.81).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    The second highest speed could be explained by ellipticity with a <3 yr orbit, or with a secondary mass of 25 M_J above that.

    “The second highest speed could be explained by ellipticity with a <3 yr orbit, or with a secondary mass of 25 M J above that.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductown data

    The de-correlation vectors for different CCDs differ significantly and indicate different behaviour for each CCD.

    “The de-correlation vectors for different CCDs differ significantly and indicate the different behaviour for each CCD.”
    Quote in the paperSubstantial claim
36 of 36

  • The authors state this as an assumption.

    The ring is optically thick.

    “We model the eclipse geometry by assuming that an optically thick ring moves in front of the stellar disc.”

  • The authors state this as an assumption.

    The ring is circular and azimuthally symmetric around J1407b.

    “We assume that the ring is circular and azimuthally symmetric around J1407b”

  • The authors state this as an assumption.

    The diameter of the ring is much larger than the diameter of the star so that the edge of the ring can be approximated as a straight line.

    “that the diameter of the ring is much larger than the diameter of the star so that the edge of the ring can be approximated as a straight line”

  • The authors state this as an assumption.

    The edge of the ring is perpendicular to its direction of motion.

    “and that the edge of the ring is perpendicular to its direction of motion, as seen in Fig. 7.”

  • The authors state this as an assumption.

    J1407b is in a circular Kepler orbit around the central star.

    “We now assume that J1407b is in a circular Kepler orbit around the central star with velocity v and semimajor axis a:”

  • The authors state this as an assumption.

    The stellar disc is approximated with a limb-darkening model from Claret & Bloemen (2011).

    “The stellar disc is approximated with a limb darkening model from Claret & Bloemen (2011).”
6 of 6

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • The distance to J1407 is 133 ± 13 pc.

    “the distance is taken to be 133 ± 13 pc with an age of 16 Myr.”

    From Mass and period limits on the ringed companion transiting the young star J1407 (2015) · cites this paper as van Werkhoven et al. 2014

    Section 3 (page unavailable) estimates J1407’s kinematic distance as 133 ± 12 pc, not 133 ± 13 pc. It also adopts an age of approximately 16 Myr, so only the quoted distance uncertainty differs. (LLM, conf=0.90)

    Experimental — accuracy not yet measured

  • Observations of rapid changes in the light curve over the course of a few hours strongly suggest that the orbital period must be short (P < ~15 yr).

    “Stability arguments favour longer periods where ξ &lt; 0 . 4 , whilst observations of rapid changes in the light curve over the course of a few hours (van Werkhoven et al. 2014) strongly suggest that the orbital period must be short ( P &lt; ∼ 15 yr).”

    From Mass and period limits on the ringed companion transiting the young star J1407 (2015) · cites this paper as van Werkhoven et al. 2014

    The Results report significant light-curve slope changes on the timescale of hours. But the Conclusions say further observations are needed to constrain the orbital period; they do not establish an upper limit of about 15 years or conclude that the period must be short. (LLM, conf=0.88)

    Experimental — accuracy not yet measured

  • The largest gradients in the J1407 light curve imply a transverse velocity of 32 ± 2 km/s for the occulting material.

    “the largest gradients in the light curve imply a transverse velocity of 32 km.s -1 for the occulting material.”

    From Mass and period limits on the ringed companion transiting the young star J1407 (2015) · cites this paper as van Werkhoven et al. 2014

    The Ring Model section derives a minimum speed from light-curve slopes, supporting the claimed relationship. But the Results section and Table 5 give 38 ± 5 km/s for the steepest measured slope, not 32 ± 2 km/s. Page numbers were not available in our copy. (LLM, conf=0.88)

    Experimental — accuracy not yet measured

  • A more detailed analysis of the SuperWASP raw data by van Werkhoven et al. (2014) and removal of a 0.1 mag amplitude, 3.2 day periodic variability due to rotational modulation by star spots show temporal structure down to a limit of 10 minutes.

    “A more detailed analysis of the Super-WASP raw data by van Werkhoven et al. (2014) and removal of a 0.1 mag amplitude, 3.2 day periodic variability due to rotational modulation by star spots show temporal structure down to a limit of 10 minutes (van Werkhoven et al. 2014).”

    From MODELING GIANT EXTRASOLAR RING SYSTEMS IN ECLIPSE AND THE CASE OF J1407B: SCULPTING BY EXOMOONS? (2015) · cites this paper as van Werkhoven et al. 2014

    Split into 2 atoms — 0 confirmed, 2 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

    Experimental — accuracy not yet measured

  • The angular diameter of the star is 65.2 ± 9.3 μas, based on a distance d = 133 ± 12 pc and radius of 0.99 ± 0.11 R.

    “The angular diameter of the star is 65.2 ± 9.3 μas, based on a distance d = 133 ± 12 pc and radius of 0.99 ± 0.11 R (van Werkhoven et al. 2014;Kenworthy et al. 2015).”

    From MODELING GIANT EXTRASOLAR RING SYSTEMS IN ECLIPSE AND THE CASE OF J1407B: SCULPTING BY EXOMOONS? (2015) · cites this paper as van Werkhoven et al. 2014

    Section 3, “Revised Stellar Parameters” (page unavailable), gives the cited distance of 133 ± 12 pc. It instead estimates the stellar radius as 1.13 ± 0.14 solar radii, not 0.99 ± 0.11, and the passages found do not give an angular diameter of 65.2 ± 9.3 μas. (LLM, conf=0.90)

    Experimental — accuracy not yet measured

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Reference-star formula does not enforce temporal overlap

    Minor

    The stated criterion requires at least 25 percent of observations to be contemporaneous. Equation (1) instead counts the union of exposure times, which always contains all target exposures and therefore passes the 25 percent threshold even for a star with no overlapping observations.

  • Stated radius uncertainty does not match the adopted radius

    Minor

    The adopted radius is 1.13 ± 0.14 solar radii, giving a fractional uncertainty of about 12.4 percent rather than 16 percent.

    Reported 16 · recomputed 12.389381

  • Orbital-radius lower bound is ten times too large

    Minor

    Using the paper's own circular-orbit relation, a speed of 21.7 km/s for a 0.9-solar-mass star gives a radius of about 1.7 au, not 17 au. Thus the stated period limit does not yield the claimed 17 au lower bound.

3 of 3

Cites

Flagged first, then by citations

2 of the 40 references couldn’t be matched to a known paper.

Research works printed but not linked: 3

  1. Baraffe, 1998, A&A, 337, 403
  2. Fraquelli, 2012, Technical Report, Kepler Archive Manual (KDMC-10008-004)
  3. Siess, 2000, A&A, 358, 593

Cited by

Sorted by citations

Related

Authors
van Werkhoven, T. I. M., Kenworthy, M. A., & Mamajek, E. E.
Affiliations
  • Leiden University (NL)
  • University of Rochester (US)
ORCID
Venue
Monthly Notices of the Royal Astronomical Society
Publisher
Oxford University Press (OUP)
Published
2014-05-24
Volume
441
Issue
4
Pages
2845-2854
ISSN
  • 0035-8711 (ISSN-L)
  • 1365-2966
DOI
10.1093/mnras/stu725
OpenAlex
W2120546577
Semantic Scholar
1aca604537a38834851176da4f518a355abe669d
Cited by
29
References
40
Citations by year
2025: 3 · 2024: 3 · 2022: 3 · 2021: 2 · 2020: 3 · 2019: 4 · 2018: 2 · 2017: 1 · 2016: 5 · 2015: 2 · 2014: 1
FWCI
1.62
Type
journal article
Language
en
Open access
Locations
Monthly Notices of the Royal Astronomical Society (publishedVersion)
Funders
  • National Science Foundation (1313029, 1008908)
  • European Commission (277116)
  • Queen's University Belfast
  • Queen's University
  • Instituto de Astrofísica de Canarias
  • Science and Technology Facilities Council
  • FP7 People: Marie-Curie Actions (FP7-PEOPLE-2010-RG)
Topics
  • Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Stellar, planetary, and galactic studies
  • Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Astro and Planetary Science
  • Physical Sciences › Physics and Astronomy › Instrumentation › Astronomy and Astrophysical Research
Keywords
eclipsing binaries, exomoons, pre-main-sequence stars, orbital eccentricity

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-11.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-11.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review