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MODELING GIANT EXTRASOLAR RING SYSTEMS IN ECLIPSE AND THE CASE OF J1407B: SCULPTING BY EXOMOONS?

Open access
Kenworthy, M. A., Mamajek, E. E.·2015·The Astrophysical Journal
DOI 10.1088/0004-637x/800/2/126
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Abstract

The light curve of 1SWASP J140747.93-394542.6, a ∼16 Myr old star in the Sco-Cen OB association, underwent a complex series of deep eclipses that lasted 56 days, centered on 2007 April. This light curve is interpreted as the transit of a giant ring system that is filling up a fraction of the Hill sphere of an unseen secondary companion, J1407b. We fit the light curve with a model of an azimuthally symmetric ring system, including spatial scales down to the temporal limit set by the star's diameter and relative velocity. The best ring model has 37 rings and extends out to a radius of 0.6 AU (9 × 10 7 km), and the rings have an estimated total mass on the order of 100 M Moon . The ring system has one clearly defined gap at 0.4 AU (6.1 × 10 7 km), which, we hypothesize, is being cleared out by a <0.8 M ⊕ exosatellite orbiting around J1407b. This eclipse and model imply that we are seeing a circumplanetary disk undergoing a dynamic transition to an exosatellite-sculpted ring structure, which is one of the first seen outside our solar system.

Integrity signals

Registry

Crossref · 10.1088/0004-637x/800/2/126

Cites

48 of 48 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

40 of 48 cited sources checked · 18 supported · 0 flagged · accuracy not yet measured

  • Premisecitation

    The light curve of 1SWASP J140747.93-394542.6 underwent a complex series of deep eclipses that lasted 56 days, centered on 2007 April.

    “The light curve of 1SWASP J140747.93-394542.6,a ∼16 Myr old star in the Sco-Cen OB association, underwent a complex series of deep eclipses that lasted 56 days, centered on 2007 April.”
    • Also stated in: § 1. INTRODUCTION · hedged
      “The Super Wide Angle Search for Planets (SuperWASP) database (Butters et al. 2010) shows that the star underwent a complex series of eclipses lasting ∼56 days around 2007 May and includes a dimming of >95%.”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites Butters et al. 2010 source

      The Abstract and §4.1 describe the WASP light-curve archive, and §3 confirms that its southern data cover 2007. However, searches for the star’s identifier and for the 56-day April 2007 eclipses found no passage describing this star or event in our copy. (LLM, conf=0.76)

      Experimental — accuracy not yet measured
    • cites Mamajek et al. (2012) source

      Section 3.1 identifies 1SWASP J140747.93-394542.6 and describes a deep eclipse with complex dimming around 2007 April 29. The paper’s abstract says significant dimming occurred on and off over at least about 54 days, and Section 3.6 says the eclipse lasted about 54 days including gradual dimming. These passages support the event and timing, but not the stated 56-day duration. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
  • Premisecitation

    Only the 2007 eclipse event is seen in the time series photometry.

    “Only the 2007 eclipse event is seen in the time series photometry, and Kenworthy et al. (2015) place constraints on the possible mass and orbital period for this companion.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Kenworthy et al. 2015 source
  • Premisecitation

    For J1407, Equation (12) gives a relative velocity of 33 km s^-1 for R = 0.99 R and Lmax = 3.1 L* day^-1.

    “The minimum velocity required to cross a limb-darkened star is derived in van Werkhoven et al. (2014), and for the case of J1407, Equation (12) gives a relative velocity of 33 km s -1 for R = 0.99 R and Lmax = 3.1 L * day -1 .”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites van Werkhoven et al. 2014 source
  • Premisecitation

    Transits of giant planets with ring systems produce a distinct and detectable light curve.

    “The transits of giant planets with ring systems produce a distinct and detectable light curve (Barnes & Fortney 2004;Tusnski & Valio 2011), and searches for the transit timing variations caused by attendant exomoons are ongoing (Kipping et al. 2012(Kipping et al. , 2013)).”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites Barnes & Fortney 2004 source
    • cites Tusnski & Valio 2011 source
  • Interpretationcitation

    The eclipses of J1407 are caused by a large ring system orbiting an unseen substellar companion, J1407b.

    “This light curve is interpreted as the transit of a giant ring system that is filling up a fraction of the Hill sphere of an unseen secondary companion, J1407b.”
    • Also stated in: § 1. INTRODUCTION · plain
      “Mamajek et al. (2012) and van Werkhoven et al. (2014) propose that these eclipses are caused by a large ring system orbiting an unseen substellar companion, dubbed J1407b.”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites Mamajek et al. (2012) source

      The Conclusion (page unavailable) models J1407’s eclipse with an orbiting companion surrounded by a disk and rings, supporting the ring-system interpretation. But it says the companion could be a low-mass star, brown dwarf, or gas giant planet; it does not establish that the companion is substellar. (LLM, conf=0.87)

      Experimental — accuracy not yet measured
    • cites van Werkhoven et al. (2014) source
    • The authors state this as an assumption: The primary star and ring system are at a similar distance from the Earth.
    • The authors state this as an assumption: The ring system is at least several times larger than the angular size of the primary star.
    • The authors state this as an assumption: The orbit of the secondary companion during the eclipse can be approximated as a straight line with constant relative velocity v.
    • The authors state this as an assumption: The rings orbit the secondary companion in Keplerian orbits that are circular.
    • The authors state this as an assumption: The ring particles in aggregate can be approximated by a smooth screen with an optical transmission τ(r) that varies as a function of radial distance r from the center of the secondary companion.
    • The authors state this as an assumption: The rings are azimuthally symmetric.
    • The authors state this as an assumption: The rings are considerably thinner than their diameter (thin ring approximation).
    • The authors state this as an assumption: All rings have well-defined edges and have a constant transmission across the width of the ring.
    • The authors state this as an assumption: The ring system lies in a plane that contains both the rings and the equatorial plane of the secondary companion (the ring plane).
  • Classified as probably not a substantial claim. 13
  • May combine two claims. 37

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

    Premisecitation

    After gas is cleared out of the planetary system, dust in the circumplanetary disk accretes into moons or remains as a ring system within the Roche limit of the planet.

    “After the gas is cleared out of the planetary system, dust in the circumplanetary disk then accretes into moons or remains as a ring system within the Roche limit of the planet (Canup & Ward 2002;Magni & Coradini 2004;Ward & Canup 2010).”
    Quote in the paperNot a substantial claim2 of 3 sources checked
    • cites Canup & Ward 2002 source

      Section 3.4 describes solids in a circumplanetary disk accumulating to form satellites. But Section 3 says satellite growth occurred while the final gas inflow was still present, not after gas was cleared. The passages do not support the alternative that solids remain as a ring within the planet’s Roche limit; page numbers were not available in our copy. (LLM, conf=0.87)

      Experimental — accuracy not yet measured
    • cites Magni & Coradini 2004 source
    • cites Ward & Canup 2010 source

      The Introduction links circumplanetary disks to satellite formation, and the Conclusion discusses solids in a disk forming satellites. Neither passage says that, after gas is cleared, dust either accretes into moons or remains as rings within the planet’s Roche limit; searches for Roche limits and rings found no such passage. The indexed copy provides section labels but no page numbers. (LLM, conf=0.84)

      Experimental — accuracy not yet measured

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

    Premisecitation

    Circumstellar gas-rich disks disperse on timescales of <10 Myr, effectively limiting the runaway growth phase for gas giant planets.

    “Circumstellar gas-rich disks disperse on timescales of <10 Myr, effectively limiting the runaway growth phase for gas giant planets (Williams & Cieza 2011).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Williams & Cieza 2011 source

      Section 5.5 (p. 23) says gaseous inner disks last less than approximately 10 Myr, but cautions that significant gas may persist longer at larger radii. Section 5 (p. 19) says disk lifetime limits the time available for planet formation; it does not specifically identify the runaway growth phase of gas giants. (LLM, conf=0.87)

      Experimental — accuracy not yet measured

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

    Premisecitation

    Kenworthy et al. (2015) conclude that J1407b is almost certainly substellar (at >3σ significance), and possibly an exoplanet.

    “They conclude that J1407b is almost certainly substellar (at >3σ significance), and possibly an exoplanet.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Kenworthy et al. 2015 source

      Section 4.1.6 (p. 14) concludes that J1407b is substellar at 3.5σ for the circular-orbit models and says a planetary mass is possible. The citing sentence omits that condition: Table 12 (p. 18) gives stellar-mass probabilities of 0.5% and 1.2% for the elliptical-orbit cases, so the >3σ figure is not established for those cases. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Interpretationcitation

    It is highly probable that this is the largest gradient in the ring system since the secondary companion velocity derived from this gradient presents a challenge to the orbital dynamics for rings.

    “It is highly probable that this is the largest gradient in the ring system since the secondary companion velocity derived from this gradient presents a challenge to the orbital dynamics for rings (see van Werkhoven et al. 2014;Kenworthy et al. 2015, for a detailed discussion).”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites van Werkhoven et al. 2014 source

      Section 6.2 identifies the highest observed light-curve slope, and the Figure 10 discussion says the speed calculated from it is incompatible with stable rings under the stated secondary-mass limit. The paper does not establish that this observed slope is highly probably the largest gradient anywhere in the ring system; it also discusses ring substructure as a possible explanation for the slope. Page numbers are unavailable in our copy. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites Kenworthy et al. 2015 source

      Section 4.2.1 (p. 15) says the highest observed light-curve gradients require a transverse velocity of up to 32 ± 2 km/s, beyond what the paper's circular-orbit models can provide. The Conclusions (p. 17) say elliptical solutions that provide this velocity pose challenges for ring stability. The paper does not establish that the particular gradient referred to as “this” is probably the largest in the entire ring system. (LLM, conf=0.83)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Findingcitation

    At least 24 ring edges are required for the number of gradient changes detected in the J1407 data, but given the sparseness of the photometric coverage, this number is almost certainly higher.

    “At least 24 ring edges are required for the number of gradient changes detected in the J1407 data (van Werkhoven et al. 2014), but given the sparseness of the photometric coverage, this number is almost certainly higher.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites van Werkhoven et al. 2014 source

  • May combine two claims.

    Premisecitation

    J1407 is a pre-main-sequence, ∼16 Myr old, 0.9 M, V = 12.3 mag K5 star at 133 pc associated with the Sco-Cen OB association.

    “1SWASP J140747.93-394542.6 (hereafter J1407) is a pre-main-sequence, ∼16 Myr old, 0.9 M , V = 12.3 mag K5 star at 133 pc associated with the Sco-Cen OB association (Mamajek et al. 2012;van Werkhoven et al. 2014;Kenworthy et al. 2015).”
    Quote in the paperNot a substantial claim3 of 3 sources checked
    • cites Mamajek et al. 2012 source

      Section 3.1 (“The Star”; page unavailable) identifies J1407 as a pre-main-sequence Sco-Cen star and gives its age as ∼16 Myr, mass as 0.9 solar masses, K5 spectral type, and V magnitude as 12.31 ± 0.03. It gives a kinematic distance of 128 ± 13 pc, not the claimed 133 pc, although 133 pc falls within that uncertainty. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites van Werkhoven et al. 2014 source
    • cites Kenworthy et al. 2015 source

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

    Premisecitation

    In the first attempt to model the system using nightly averaged photometry, Mamajek et al. (2012) posited at least four large rings girding J1407b.

    “In the first attempt to model the system using nightly averaged photometry, Mamajek et al. (2012) posited at least four large rings girding J1407b.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Mamajek et al. (2012) source

      Section 3.7, “A Preliminary Model” (page not available), describes a fit to the daily averaged light curve with a thick inner disk and two rings; it says an additional outer ring is needed but is not included in that model. This supports four proposed dust structures around the companion, but not the claim that the initial model contained at least four rings. (LLM, conf=0.87)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    The orbit for β Pictoris b is close to edge-on, indicating that it might transit its parent star.

    “The orbit for β Pictoris b is close to edge-on (Nielsen et al. 2014), indicating that it might transit its parent star.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Nielsen et al. 2014 source

  • May combine two claims.

    Interpretationcitation

    A circular orbit is possible if the rings are clumpy and the clump orbital motion vectorially adds to the J1407b orbital motion, but this requires a series of coincidences to generate a large gradient at the appropriate epochs.

    “A circular orbit is possible if the rings are themselves clumpy in nature and the clump orbital motion vectorially adds to the J1407b orbital motion van Werkhoven et al. (2014), but this again requires a series of coincidences to occur to generate a large gradient at the appropriate epochs.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites van Werkhoven et al. 2014 source

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

    Premisecitation

    Fomalhaut b is a comoving companion to the nearby 400 Myr old star, moving on an eccentric orbit.

    “Fomalhaut b is a comoving companion to the nearby 400 Myr old star, moving on an eccentric orbit (Kalas et al. 2013;Mamajek 2012).”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites Kalas et al. 2013 source
    • cites Mamajek 2012 source

  • May combine two claims.

    Premisecitation

    J1407b is substellar and almost certainly of planetary mass.

    “J1407b is substellar and almost certainly of planetary mass (Kenworthy et al. 2015).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Kenworthy et al. 2015 source

      Section 4.1.6 (p. 14) concludes that J1407b is substellar, but says it is equally likely to be a brown dwarf or a planetary-mass object for disk-size values ξ > 0.3. The Conclusions (p. 17) likewise describe it as likely to be planetary- or brown-dwarf-mass, not almost certainly planetary-mass. (LLM, conf=0.90)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    Constraints suggest a minimum eccentricity of 0.7 and a minimum period of 10 yr for J1407b.

    “Constraints presented in Kenworthy et al. (2015) suggest a minimum eccentricity of 0.7 and a minimum period of 10 yr.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Kenworthy et al. 2015 source

      Section 4.2.6 (p. 17) says the elliptical-orbit solution requires eccentricity greater than 0.7. The paper does not establish a minimum period of 10 years: Section 4.1.3 (p. 12) rules out periods below 850 days and a range around 4–7 years, while the Conclusions (p. 17) suggest a period shorter than about 15 years. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    The period of J1407b could be as short as 10 yr and the mass can be greater than 80 M_Jup, but this mass is considered highly unlikely, with a probability of less than 1.2%.

    “although we note that the period could be as short as 10 yr and the mass can be greater than 80 M Jup , but this mass is considered highly unlikely, with a probability of less than 1.2%.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Kenworthy et al. 2015 source

      Section 4.1.6 (p. 14) allows a mass above 80 M_Jup at some orbital periods, and Table 11 (p. 15) gives probable periods near 10 years. The paper finds such a mass highly unlikely, but Table 12 (p. 18) gives a probability of exactly 1.2% for one elliptical-orbit model, not less than 1.2% for every model. (LLM, conf=0.86)

      Experimental — accuracy not yet measured

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

    Premisecitation

    A large ring system around Fomalhaut b is thought to cause the anomalously bright flux seen in optical images.

    “A large ring system around the planet is thought to cause the anomalously bright flux seen in optical images.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Kalas et al. 2013 source

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

    Findingnone given

    There are 16,489 photometric data points covering the 2007 observing season of J1407 (MJD 54,131.96 to 54,306.72).

    “There are 16,489 photometric data points covering the 2007 observing season of J1407 (MJD 54,131.96 to 54,306.72).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The derived ring model is consistent with the data, yielding a diameter of 1.2 AU for the ring system.

    “Our derived ring model is consistent with the data, yielding a diameter of 1.2 AU for the ring system.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingnone given

    Gaps in the ring system are seen either directly as the photometric flux from J1407 returning to full transmission during the eclipse or indirectly as a fit of the model to intermediate transmission photometric gradients.

    “Gaps in the ring system are seen either directly as the photometric flux from J1407 returning to full transmission during the eclipse or indirectly as a fit of the model to intermediate transmission photometric gradients.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    The order-of-magnitude estimate for the total mass of the rings is ∼100 M_Moon, close to the mass of the Earth.

    “The order-of-magnitude estimate for the total mass of the rings is ∼100 M Moon , close to the mass of the Earth.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: Dust opacity κ ∼ 0.02 cm^2 g^-1 for unity optical depth.

  • May combine two claims.

    Findingown data

    There is no recorded photometry within 3 days of t, so the J1407b data cannot be examined for Δt1.

    “We cannot examine the J1407b data for Δt 1 as there is no recorded photometry within 3 days of t .”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The size of the ring system is considerably larger than the Roche radius for the secondary companion and fills a significant fraction of the Hill radius.

    “The size of the ring system is considerably larger than the Roche radius for the secondary companion and fills a significant fraction of the Hill radius.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Only one eclipse of J1407 is seen in the publicly available photometric data, so the orbital period of J1407b and whether it is bound to J1407 in a closed orbit are unknown.

    “Only one eclipse of J1407 is seen in the publically available photometric data, and so we do not know the orbital period of J1407b or even whether it is bound to J1407 in a closed orbit.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Interpretationown data

    The large size of the ring system presents a challenge to what type of orbit it must have around the primary star.

    “The large size of the ring system presents a challenge to what type of orbit it must have around the primary star, which we address in Section 5.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    The eclipse and model imply that we are seeing a circumplanetary disk undergoing a dynamic transition to an exosatellite-sculpted ring structure, one of the first seen outside our solar system.

    “This eclipse and model imply that we are seeing a circumplanetary disk undergoing a dynamic transition to an exosatellite-sculpted ring structure, which is one of the first seen outside our solar system.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The primary star and ring system are at a similar distance from the Earth.
    • The authors state this as an assumption: The ring system is at least several times larger than the angular size of the primary star.
    • The authors state this as an assumption: The orbit of the secondary companion during the eclipse can be approximated as a straight line with constant relative velocity v.
    • The authors state this as an assumption: The rings orbit the secondary companion in Keplerian orbits that are circular.
    • The authors state this as an assumption: The ring particles in aggregate can be approximated by a smooth screen with an optical transmission τ(r) that varies as a function of radial distance r from the center of the secondary companion.
    • The authors state this as an assumption: The rings are azimuthally symmetric.
    • The authors state this as an assumption: The rings are considerably thinner than their diameter (thin ring approximation).
    • The authors state this as an assumption: All rings have well-defined edges and have a constant transmission across the width of the ring.
    • The authors state this as an assumption: The ring system lies in a plane that contains both the rings and the equatorial plane of the secondary companion (the ring plane).

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    The function G(t) represents the maximum flux change possible between a fully transparent and fully opaque ring.

    “The function G(t) represents the maximum flux change possible between a fully transparent and fully opaque ring.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductown data

    The photometric data are sparse (the binned data cover 11.3% of the total 2007 season), and so no unique solutions for the disk geometry and τ(r) are found.

    “The photometric data are sparse (the binned data cover 11.3% of the total 2007 season), and so no unique solutions for the disk geometry and τ (r) are found.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    The finite diameter of the star breaks this degeneracy, and so the ingress and egress light curves for a given ring edge radius are not identical.

    “The finite diameter of the star breaks this degeneracy, and so the ingress and egress light curves for a given ring edge radius are not identical.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S1 (asserted).

    Interpretationnone given

    The gap at 0.4 AU is being cleared out by a <0.8 M_Earth exosatellite orbiting around J1407b.

    “The ring system has one clearly defined gap at 0.4 AU (6.1 × 10 7 km), which, we hypothesize, is being cleared out by a <0.8 M ⊕ exosatellite orbiting around J1407b.”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: The primary star and ring system are at a similar distance from the Earth.
    • The authors state this as an assumption: The ring system is at least several times larger than the angular size of the primary star.
    • The authors state this as an assumption: The orbit of the secondary companion during the eclipse can be approximated as a straight line with constant relative velocity v.
    • The authors state this as an assumption: The rings orbit the secondary companion in Keplerian orbits that are circular.
    • The authors state this as an assumption: The ring particles in aggregate can be approximated by a smooth screen with an optical transmission τ(r) that varies as a function of radial distance r from the center of the secondary companion.
    • The authors state this as an assumption: The rings are azimuthally symmetric.
    • The authors state this as an assumption: The rings are considerably thinner than their diameter (thin ring approximation).
    • The authors state this as an assumption: All rings have well-defined edges and have a constant transmission across the width of the ring.
    • The authors state this as an assumption: The ring system lies in a plane that contains both the rings and the equatorial plane of the secondary companion (the ring plane).

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

    Interpretationreasoning

    A circular orbit for J1407b would mean that any ring system would not be subject to gravitational perturbations due to the orbit of J1407b, and so appears preferable for ring stability.

    “A circular orbit for J1407b would mean that any ring system would not be subject to gravitational perturbations due to the orbit of J1407b, and so appears preferable for ring stability.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Two processes that can clear gaps are (1) formation of exomoons gravitationally clearing gaps, and (2) Lindblad resonances caused by unseen exosatellites at larger radii.

    “Two such processes are (1) the formation of exomoons that are gravitationally clearing out these gaps, such as those sculpting the A-ring gaps in Saturn, and (2) the presence of Lindbad resonances, caused by the presence of unseen exosatellites at larger radii.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Gaps in the rings of solar system giant planets are caused either directly by the gravitational clearing of a satellite or indirectly by a Lindblad resonance due to a satellite on a larger orbit.

  • May combine two claims.

    Interpretationreasoning

    For these eccentric orbits, the ring system is within the Hill sphere for most of its orbit, but at periastron the Hill sphere shrinks below the size of the outermost rings, challenging the stability of the ring system.

    “One conclusion with these eccentric orbits is that the ring system is within the Hill sphere for most of its orbit, but at periastron the Hill sphere shrinks down below the size of the outermost rings, providing a challenge for investigations into the stability of this ring system.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    The longest period is unconstrained in this model, as very highly eccentric orbits are possible with the long axis pointing toward Earth, but the probability of such a precise alignment becomes increasingly unlikely.

    “The longest period is unconstrained in this model, as very highly eccentric orbits are possible with the long axis pointing toward Earth, but the probability of such a precise alignment becomes increasingly unlikely.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    The Phoebe ring's non-coplanarity is due to the dominance of solar perturbations over the gravitational perturbation caused by the J2 contribution of Saturn's gravitational field.

    “This is due to the dominance of solar perturbations over the gravitational perturbation caused by the J 2 contribution of Saturn's gravitational field.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Verbiscer et al. 2009 source

  • May combine two claims.

    Interpretationnone given

    The mass of the rings is dependent on the orbital parameters of J1407b, the effective dust opacity in the rings, the detailed dust size distribution, and the unknown ring structure where there is no photometric constraint.

    “The mass of the rings is dependent on the orbital parameters of J1407b, the effective dust opacity in the rings, the detailed dust size distribution, and the unknown ring structure where there is no photometric constraint.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: Dust opacity κ ∼ 0.02 cm^2 g^-1 for unity optical depth.

  • May combine two claims.

    Interpretationreasoning

    Truncating the eccentricity to be between 0.7 and 0.8 gives a probable mass of 24 M_Jup and a probable period of 13.3 yr.

    “Truncating the eccentricity to be between 0.7 and 0.8 gives a probable mass of 24 M Jup and a probable period of 13.3 yr.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    The Phoebe ring around Saturn is not coplanar with the other rings but lies in the plane of Saturn's orbit.

    “In the case of the largest ring around Saturn, the Phoebe ring is not coplanar with the other rings (Verbiscer et al. 2009) but lies in the plane of Saturn's orbit.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Verbiscer et al. 2009 source

  • May combine two claims.

    Interpretationreasoning

    β Pictoris b's age of 22 Myr is similar to the J1407 system, implying that a low-mass companion could have a fast rotation period, leading to a larger oblateness and J2 contribution that could hold ring structures in the equatorial plane out to larger radii.

    “Its age of 22 Myr (Mamajek & Bell 2014) is similar to the J1407 system, implying that a low-mass companion could have a fast rotation period, leading to a larger oblateness and corresponding J 2 contribution, that could hold ring structures in the equatorial plane out to larger radii.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Mamajek & Bell 2014 source

  • May combine two claims.

    Interpretationreasoning

    For a secondary companion mass of 23.8 M_Jup, the satellite mass corresponding to the gap is 0.8 M_Earth and its orbital period is 1.7 yr.

    “For the case of 23.8 M Jup this corresponds to a satellite mass of 0.8 M ⊕ and an orbital period of 1.7 yr.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The gap is equal to the diameter of the Hill sphere of a satellite orbiting around the secondary companion and clearing out the ring.

  • May combine two claims.

    Interpretationreasoning

    The estimated size of the ring system is two orders of magnitude larger than the Roche limit for the central substellar mass, and rings outside the Roche limit are expected to accrete into satellites on timescales shorter than gigayears.

    “The estimated size of the ring system is two orders of magnitude larger than the Roche limit for the central substellar mass, and so the rings outside the Roche limit are expected to accrete into satellites on timescales shorter then gigayears.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    This structure is in a transitional state, with the rings at large radii undergoing accretion to form exosatellites orbiting the secondary companion.

    “This implies that this structure is in a transitional state, with the rings at large radii undergoing accretion to form exosatellites orbiting the secondary companion.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    β Pictoris b has a rotation period of ∼8 hr, faster than that of the other gas giants in the solar system.

    “The planet β Pictoris b was recently shown to have a rotation period of ∼8 hr (Snellen et al. 2014), faster than that of the other gas giants in the solar system.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Snellen et al. 2014 source

  • May combine two claims.

    Interpretationreasoning

    Transverse velocities derived from the light-curve gradients strongly rule out long orbital periods, but the lack of a second primary eclipse in time-series photometry rules out short orbital periods.

    “Transverse velocities derived from the light-curve gradients, however, strongly rule out long orbital periods, but the lack of a second primary eclipse in time-series photometry rules out short orbital periods.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    The satellite in J1407b has a similar mass (to an order of magnitude) as the rings, implying that further accretion into satellites is ongoing.

    “It is interesting to note that the satellite in J1407b has a similar mass (to an order of magnitude) as the rings, implying that further accretion into satellites is ongoing.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    The discrepancies between the model and light curves imply an error in the determined geometry of the ring plane and/or that the rings are not coplanar.

    “These discrepancies imply an error in the determined geometry of the ring plane and/or that the rings are not coplanar.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    When the light curve is folded at time of closest approach, the coverage approximately doubles to 20%, implying at least 120 ring edges in the J1407b system.

    “When the light curve is folded at time of closest approach, the coverage approximately doubles to 20%.This implies that there are at least 24/0.2≈ 120 ring edges in the J1407b system.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Anomalous photometry of β Pictoris in 1981 has been attributed to an extended system of material surrounding the planet, and the anomalous photometry extends over 30 days, implying material extending out to 0.1 of the Hill radius of the planet.

    “Anomalous photometry of β Pictoris in 1981 (Lecavelier Des Etangs et al. 1995) has also been attributed to an extended system of material surrounding the planet, and the anomalous photometry extends over 30 days, implying that there is material extending out to 0.1 of the Hill radius of the planet.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Lecavelier Des Etangs et al. 1995

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

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

    Interpretationnone given

    The orbital period of J1407b is on the order of a decade or possibly longer.

    “The orbital period of J1407b is on the order of a decade or possibly longer.”
    Quote in the paperNot a substantial claim
46 of 46

  • The authors state this as an assumption.

    The primary star and ring system are at a similar distance from the Earth.

    “We assume that the primary star and ring system are at a similar distance from the Earth, and that the ring system is at least several times larger than the angular size of the primary star.”

  • The authors state this as an assumption.

    The ring system is at least several times larger than the angular size of the primary star.

    “We assume that the primary star and ring system are at a similar distance from the Earth, and that the ring system is at least several times larger than the angular size of the primary star.”

  • The authors state this as an assumption.

    The orbit of the secondary companion during the eclipse can be approximated as a straight line with constant relative velocity v.

    “We approximate the orbit of the secondary for the duration of the eclipse as being a straight line, with constant relative velocity of v.”

  • The authors state this as an assumption.

    The rings orbit the secondary companion in Keplerian orbits that are circular.

    “The rings are composed of individual particles that orbit the secondary companion in Keplerian orbits, assumed circular.”

  • The authors state this as an assumption.

    The ring particles in aggregate can be approximated by a smooth screen with an optical transmission τ(r) that varies as a function of radial distance r from the center of the secondary companion.

    “These particles scatter light out of any incident beam and in aggregate are approximated by a smooth screen with an optical transmission of τ (r) that varies as a function of radial distance r from the center of the secondary companion.”

  • The authors state this as an assumption.

    The rings are azimuthally symmetric.

    “The rings are assumed to be azimuthally symmetric; the inclination of the ring plane as seen from the Earth is i disk (with 0 o being face-on), and the projected angle between the normal of the secondary companion's orbit and the normal of the ring plane is φ disk .”

  • The authors state this as an assumption.

    The rings are considerably thinner than their diameter (thin ring approximation).

    “The rings are assumed to be considerably thinner than their diameter, i.e., a”

  • The authors state this as an assumption.

    All rings have well-defined edges and have a constant transmission across the width of the ring.

    “We assume that all the rings have well-defined edges and have a constant transmission across the width of the ring (with some assumed constant τ ); see Figure 2.”

  • The authors state this as an assumption.

    The ring system lies in a plane that contains both the rings and the equatorial plane of the secondary companion (the ring plane).

    “Surrounding the secondary companion is a ring system in a plane that contains both the rings and the equatorial plane of the secondary companion, which we refer to as the ring plane.”

  • The paper relies on this without support.

    Gaps in the rings of solar system giant planets are caused either directly by the gravitational clearing of a satellite or indirectly by a Lindblad resonance due to a satellite on a larger orbit.

    “Gaps in the rings of solar system giant planets are caused either directly by the gravitational clearing of a satellite or indirectly by a Lindblad resonance due to a satellite on a larger orbit.”

  • The authors state this as an assumption.

    The gap is equal to the diameter of the Hill sphere of a satellite orbiting around the secondary companion and clearing out the ring.

    “If we assume that the gap is equal to the diameter of the Hill sphere of a satellite orbiting around the secondary companion and clearing out the ring”

  • The paper relies on this without support.

    The mean projected separation between stars in the field is ≈10^3 AU.

    “The mean projected separation between stars in the field is ≈10 3 AU.”

  • The authors state this as an assumption.

    Dust opacity κ ∼ 0.02 cm^2 g^-1 for unity optical depth.

    “We estimate the mass of the individual rings by assuming a dust opacity of κ ∼ 0.02 cm 2 g -1 for unity optical depth, as assumed in Mamajek et al. (2012) for their estimate.”

  • The paper relies on this without support.

    The ratio of the mass of the densest rings around Saturn (the B ring system) to that of the largest satellite, Titan, is approximately 1/4000.

    “The ratio of the mass of the densest rings around Saturn (the B ring system) to that of the largest satellite, Titan, is approximately 1/4000.”
14 of 14

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?

  • An orbital period of 11 years only permitted eccentricities up to e=0.8.

    “An orbital period of 11 year only permitted eccentricities up to e 0.8 (Von Werkhoven et al., 2014;Kenworthy and Mamajek 2015;Rieder and Kenworthy 2016), which we take as an upper limit for eccentricity in our models.”

    From A Self-Gravitating Exoring Around J1407b and Implications for In-Situ Exomoon Formation (2022) · cites this paper as Kenworthy and Mamajek 2015

    Section 5.2 gives a minimum period of 10 years and a minimum eccentricity of 0.7; it does not impose an eccentricity ceiling of 0.8 for an 11-year orbit. It describes the 0.7–0.8 range as a truncation used to estimate a probable 13.3-year period, and says very highly eccentric orbits remain possible. Table 3 also considers eccentricities up to 0.9. The copy provides no specific eccentricity limit at 11 years. (LLM, conf=0.86)

    Checked by a reasoning model — may be wrong.

    Experimental — accuracy not yet measured

  • Modelling by Kenworthy & Mamajek (2015) found the most significant gap at 0.4 AU, with other small gaps, most notably a ~0.00668 AU wide gap at ~0.34 AU.

    “Modelling of a planetary ring transit by Kenworthy &amp; Mamajek (2015) found that the most significant gap was located at 0.4𝐴𝑈 , yet other small gaps appear on the ring model. Most notable is a ~0.00668𝐴𝑈 wide gap at ~0.34𝐴𝑈 .”

    From Mean motion resonances with nearby moons: an unlikely origin for the gaps observed in the ring around the exoplanet J1407b (2019) · cites this paper as Kenworthy & Mamajek 2015

    Section 4 and the Conclusions identify a prominent gap near 6.1 × 10^7 km (about 0.4 AU), and the paper reports other gaps in its ring models. Table 2 lists ring boundaries near 0.34 AU, but it does not establish a gap there with the claimed width of ~0.00668 AU; the Conclusions instead give the prominent 0.4-AU gap a width of 4 × 10^6 km. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

  • The ring around J1407b extends 0.6 AU radially from the planet.

    “A possible solution to the unusual transit of J1407b across the primary was shown to be a large planetary ring that extends 0.6𝐴𝑈 radially from the planet.”

    From Mean motion resonances with nearby moons: an unlikely origin for the gaps observed in the ring around the exoplanet J1407b (2019) · cites this paper as Kenworthy & Mamajek 2015

  • The 2007 transit was likely caused by a secondary companion with mass 5-20 MJup and a ring system filling a significant fraction of its Hill sphere.

    “Subsequent work analysing the single transit suggests the cause was by a secondary companion with a mass 5 -20 M Jup (Mentel et al., 2018) and a ring system filling a significant fraction of its Hill sphere (Van Werkhoven et al., 2014;Kenworthy and Mamajek 2015;Rieder and Kenworthy 2016).”

    From A Self-Gravitating Exoring Around J1407b and Implications for In-Situ Exomoon Formation (2022) · cites this paper as Kenworthy and Mamajek 2015

  • The original transit suggested a gap in the ring could be indirect evidence of an exomoon.

    “A key observation of the original transit suggested a gap in the ring could be indirect evidence of an exomoon.”

    From A Self-Gravitating Exoring Around J1407b and Implications for In-Situ Exomoon Formation (2022) · cites this paper as Kenworthy and Mamajek 2015

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.

  • The concluding satellite-mass limit does not follow the stated mass scaling

    Major

    The paper's formula gives 0.8 Earth masses at a companion mass of 23.8 Jupiter masses and scales the satellite mass proportionally with companion mass. At the 28 Jupiter masses used in the conclusion, it gives approximately 0.94 Earth masses, not less than 0.8.

1 of 1

Cites

Flagged first, then by citations

2 of the 50 references couldn’t be matched to a known paper.

Research works printed but not linked: 4

  1. 10.1051/0004-6361:20030430 · DOI
  2. Graczyk, 2011, AcA, 61, 103
  3. Lecavelier Des Etangs, 1995, A&A, 299, 557
  4. White, 1987, VA, 30, 13

Cited by

Sorted by citations

Related

Authors
Kenworthy, M. A., & Mamajek, E. E.
Affiliations
  • Leiden University (NL)
  • University of Rochester (US)
ORCID
Venue
The Astrophysical Journal
Publisher
American Astronomical Society
Published
2015-02-18
Volume
800
Issue
2
Pages
126
ISSN
  • 0004-637X (ISSN-L)
  • 1538-4357
DOI
10.1088/0004-637x/800/2/126
OpenAlex
W2156132705
Semantic Scholar
700a0cad85744653bc2a30139860bae499ec0b5f
Cited by
123
References
50
Citations by year
2026: 3 · 2025: 5 · 2024: 14 · 2023: 5 · 2022: 5 · 2021: 12 · 2020: 12 · 2019: 13 · 2018: 8 · 2017: 19 · 2016: 17 · 2015: 10
FWCI
10.23
Type
journal article
Language
en
Open access
Licence
Locations
  • The Astrophysical Journal (publishedVersion)
  • arXiv (Cornell University) (submittedVersion)
  • Leiden Repository (Leiden University) (submittedVersion)
  • Data Archiving and Networked Services (DANS) (submittedVersion, other-oa)
  • arXiv (Cornell University)
Funders
  • National Science Foundation (1313029)
  • University of Leicester
  • Queen's University Belfast
  • Queen's University
  • Keele University
  • Science and Technology Facilities Council
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 › Astronomy and Astrophysics › Astrophysics and Star Formation Studies
Keywords
exomoons, circumplanetary disks, ring gaps, Hill sphere, light curve modeling

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.

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