We investigate the possible origin of the transiting giant planet WD1856+534b, the first strong exoplanet candidate orbiting a white dwarf, through high-eccentricity migration (HEM) driven by the Lidov-Kozai (LK) effect. The host system's overall architecture is a hierarchical quadruple in the '2+2' configuration, owing to the presence of a tertiary companion system of two M-dwarfs. We show that a secular inclination resonance in 2+2 systems can significantly broaden the LK window for extreme eccentricity excitation (e > 0.999), allowing the giant planet to migrate for a wide range of initial orbital inclinations. Octupole effects can also contribute to the broadening of this 'extreme' LK window. We suggest that WD1856+534b likely migrated from a distance of ~30-60 AU, corresponding to a semi-major axis ~10-20 AU during the host's main-sequence phase. We discuss possible difficulties of all flavours of HEM affecting the occurrence rate of short-period giant planets around white dwarfs.
{"title":"Enhanced Lidov–Kozai migration and the formation of the transiting giant planet WD 1856+534 b","authors":"Christopher E. O’Connor, B. Liu, D. Lai","doi":"10.1093/mnras/staa3723","DOIUrl":"https://doi.org/10.1093/mnras/staa3723","url":null,"abstract":"We investigate the possible origin of the transiting giant planet WD1856+534b, the first strong exoplanet candidate orbiting a white dwarf, through high-eccentricity migration (HEM) driven by the Lidov-Kozai (LK) effect. The host system's overall architecture is a hierarchical quadruple in the '2+2' configuration, owing to the presence of a tertiary companion system of two M-dwarfs. We show that a secular inclination resonance in 2+2 systems can significantly broaden the LK window for extreme eccentricity excitation (e > 0.999), allowing the giant planet to migrate for a wide range of initial orbital inclinations. Octupole effects can also contribute to the broadening of this 'extreme' LK window. We suggest that WD1856+534b likely migrated from a distance of ~30-60 AU, corresponding to a semi-major axis ~10-20 AU during the host's main-sequence phase. We discuss possible difficulties of all flavours of HEM affecting the occurrence rate of short-period giant planets around white dwarfs.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85172148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-06DOI: 10.1051/0004-6361/202039579
B. Carry, W. Thuillot, F. Spoto, P. David, J. Berthier, P. Tanga, F. Mignard, S. Bouquillon, R. Mendez, J. Rivet, A. L. V. Suu, A. Dell’Oro, G. Fedorets, B. Frezouls, M. Granvik, J. Guiraud, K. Muinonen, C. Panem, T. Pauwels, W. Roux, G. Walmsley, J. Petit, L. Abe, V. Ayvazian, K. Baillié, A. Baransky, P. Bendjoya, M. Dennefeld, J. Desmars, S. Eggl, V. Godunova, D. Hestroffer, R. Inasaridze, V. Kashuba, Y. Krugly, I. Molotov, V. Robert, A. Simon, I. Sokolov, D. Souami, V. Tarady, F. Taris, V. Troianskyi, V. Vasylenko, D. Vernet
Since July 2014, the ESA Gaia mission has been surveying the entire sky down to magnitude 20.7 in the visible. In addition to the millions of stars, thousands of Solar System Objects (SSOs) are observed daily. By comparing their positions to those of known objects, a daily processing pipeline filters known objects from potential discoveries. However, owing to Gaia's specific scanning law designed for stars, potential newly discovered moving objects are characterized by very few observations, acquired over a limited time. This aspect was recognized early in the design of the Gaia data processing. A daily processing pipeline dedicated to these candidate discoveries was set up to release calls for observations to a network of ground-based telescopes. Their aim is to acquire follow-up astrometry and to characterize these objects. From the astrometry measured by Gaia, preliminary orbital solutions are determined, allowing to predict the position of these potentially new discovered objects in the sky accounting for the large parallax between Gaia and the Earth (separated by 0.01 au). A specific task within the Gaia Consortium has been responsible for the distribution of requests for follow-up observations of potential Gaia SSO discoveries. Since late 2016, these calls for observations (called alerts) are published daily via a Web interface, freely available to anyone world-wide. Between November 2016 and July 2020, over 1700 alerts have been published, leading to the successful recovery of more than 200 objects. Among those, six have provisional designation assigned with the Gaia observations, the others being previously known objects with poorly characterized orbits, precluding identification at the time of Gaia observations. There is a clear trend for objects with a high inclination to be unidentified, revealing a clear bias in the current census of SSOs against high inclination populations.
{"title":"Potential asteroid discoveries by the ESA Gaia mission","authors":"B. Carry, W. Thuillot, F. Spoto, P. David, J. Berthier, P. Tanga, F. Mignard, S. Bouquillon, R. Mendez, J. Rivet, A. L. V. Suu, A. Dell’Oro, G. Fedorets, B. Frezouls, M. Granvik, J. Guiraud, K. Muinonen, C. Panem, T. Pauwels, W. Roux, G. Walmsley, J. Petit, L. Abe, V. Ayvazian, K. Baillié, A. Baransky, P. Bendjoya, M. Dennefeld, J. Desmars, S. Eggl, V. Godunova, D. Hestroffer, R. Inasaridze, V. Kashuba, Y. Krugly, I. Molotov, V. Robert, A. Simon, I. Sokolov, D. Souami, V. Tarady, F. Taris, V. Troianskyi, V. Vasylenko, D. Vernet","doi":"10.1051/0004-6361/202039579","DOIUrl":"https://doi.org/10.1051/0004-6361/202039579","url":null,"abstract":"Since July 2014, the ESA Gaia mission has been surveying the entire sky down to magnitude 20.7 in the visible. In addition to the millions of stars, thousands of Solar System Objects (SSOs) are observed daily. By comparing their positions to those of known objects, a daily processing pipeline filters known objects from potential discoveries. However, owing to Gaia's specific scanning law designed for stars, potential newly discovered moving objects are characterized by very few observations, acquired over a limited time. This aspect was recognized early in the design of the Gaia data processing. A daily processing pipeline dedicated to these candidate discoveries was set up to release calls for observations to a network of ground-based telescopes. Their aim is to acquire follow-up astrometry and to characterize these objects. From the astrometry measured by Gaia, preliminary orbital solutions are determined, allowing to predict the position of these potentially new discovered objects in the sky accounting for the large parallax between Gaia and the Earth (separated by 0.01 au). A specific task within the Gaia Consortium has been responsible for the distribution of requests for follow-up observations of potential Gaia SSO discoveries. Since late 2016, these calls for observations (called alerts) are published daily via a Web interface, freely available to anyone world-wide. Between November 2016 and July 2020, over 1700 alerts have been published, leading to the successful recovery of more than 200 objects. Among those, six have provisional designation assigned with the Gaia observations, the others being previously known objects with poorly characterized orbits, precluding identification at the time of Gaia observations. There is a clear trend for objects with a high inclination to be unidentified, revealing a clear bias in the current census of SSOs against high inclination populations.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81315756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-01DOI: 10.1051/0004-6361/202038512
B. Rousseau, M. C. Sanctis, A. Raponi, M. Ciarniello, E. Ammannito, A. Frigeri, M. Ferrari, S. Angelis, F. Tosi, S. E. Schroder, C. Raymond, C. T. R. IAPS-INAF, Via Fosso del Cavaliere 100, Romé, Italy, I. Agency, V. Politecnico, Deutsche Forschungsanstalt für Luft und Raumfahrt, Berlin, Germany, J. P. Laboratory, C. I. O. Technology., Pasadena, Usa, Earth Planetary, S. Sciences, U. Angeles, Los Angeles, Ca
We study the surface of Ceres at visible wavelengths, as observed by the Visible and InfraRed mapping spectrometer (VIR) onboard the Dawn spacecraft, and analyze the variations of various spectral parameters across the whole surface. We also focus on several noteworthy areas of the surface of this dwarf planet. We made use of the newly corrected VIR visible data to build global maps of a calibrated radiance factor at 550 nm, with two color composites and three spectral slopes between 400 and 950 nm. We have made these maps available for the community via the Aladin Desktop software. Ceres surface shows diverse spectral behaviors in the visible range. The color composite and the spectral slope between 480 and 800 nm highlight fresh impact craters and young geologic formations of endogenous origin, which appear bluer than the rest of the surface. The steep slope before 465 nm displays very distinct variations and may be a proxy for the absorptions caused by the $O_2^{-}$ -> $Fe^{3+}$ or the $2Fe^{3+}$ -> $Fe^{2+} + Fe^{4+}$ charge transfer, if the latter are found to be responsible for the drop in this spectral range. We notice several similarities between the spectral slopes and the abundance of phyllosilicates detected in the infrared by the VIR, whereas no correlation can be clearly established with carbonate species. The region of the Dantu impact crater presents a peculiar spectral behavior (especially through the color and the spectral slope before 465 nm) suggesting a change in composition or in the surface physical properties that is not observed elsewhere on Ceres.
{"title":"The surface of (1) Ceres in visible light as seen by Dawn/VIR","authors":"B. Rousseau, M. C. Sanctis, A. Raponi, M. Ciarniello, E. Ammannito, A. Frigeri, M. Ferrari, S. Angelis, F. Tosi, S. E. Schroder, C. Raymond, C. T. R. IAPS-INAF, Via Fosso del Cavaliere 100, Romé, Italy, I. Agency, V. Politecnico, Deutsche Forschungsanstalt für Luft und Raumfahrt, Berlin, Germany, J. P. Laboratory, C. I. O. Technology., Pasadena, Usa, Earth Planetary, S. Sciences, U. Angeles, Los Angeles, Ca","doi":"10.1051/0004-6361/202038512","DOIUrl":"https://doi.org/10.1051/0004-6361/202038512","url":null,"abstract":"We study the surface of Ceres at visible wavelengths, as observed by the Visible and InfraRed mapping spectrometer (VIR) onboard the Dawn spacecraft, and analyze the variations of various spectral parameters across the whole surface. We also focus on several noteworthy areas of the surface of this dwarf planet. We made use of the newly corrected VIR visible data to build global maps of a calibrated radiance factor at 550 nm, with two color composites and three spectral slopes between 400 and 950 nm. We have made these maps available for the community via the Aladin Desktop software. Ceres surface shows diverse spectral behaviors in the visible range. The color composite and the spectral slope between 480 and 800 nm highlight fresh impact craters and young geologic formations of endogenous origin, which appear bluer than the rest of the surface. The steep slope before 465 nm displays very distinct variations and may be a proxy for the absorptions caused by the $O_2^{-}$ -> $Fe^{3+}$ or the $2Fe^{3+}$ -> $Fe^{2+} + Fe^{4+}$ charge transfer, if the latter are found to be responsible for the drop in this spectral range. We notice several similarities between the spectral slopes and the abundance of phyllosilicates detected in the infrared by the VIR, whereas no correlation can be clearly established with carbonate species. The region of the Dantu impact crater presents a peculiar spectral behavior (especially through the color and the spectral slope before 465 nm) suggesting a change in composition or in the surface physical properties that is not observed elsewhere on Ceres.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89289485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-30DOI: 10.1051/0004-6361/202039173
J. Hagelberg, N. Engler, C. Fontanive, S. Daemgen, S. Quanz, J. Kuhn, M. Reggiani, M. Meyer, R. Jayawardhana, V. B. I. F. T. Physics, Astrophysics, E. Zurich, Switzerland., G. Observatory, U. Geneva, Center for Space, Habitability, U. Bern, Bern, Institute of Astrophysics, K. Leuven, Celestijnlaan 200D, Leuven, Belgium, U. Michigan, A. Department, Usa, D. Astronomy, C. University, Ithaca, Ny, NasaGsfc
Recent surveys indicate that planets in binary systems are more abundant than previously thought, which is in agreement with theoretical work on disc dynamics and planet formation in binaries. In order to measure the abundance and physical characteristics of wide-orbit giant exoplanets in binary systems, we have designed the 'VIsual Binary Exoplanet survey with Sphere' (VIBES) to search for planets in visual binaries. It uses the SPHERE instrument at VLT to search for planets in 23 visual binary and four visual triple systems with ages of <145 Myr and distances of <150 pc. We used the IRDIS dual-band imager on SPHERE to acquire high-contrast images of the sample targets. For each binary, the two components were observed at the same time with a coronagraph masking only the primary star. For the triple star, the tight components were treated as a single star for data reduction. This enabled us to effectively search for companions around 50 individual stars in binaries and four binaries in triples. We derived upper limits of $<$13.7% for the frequency of sub-stellar companions around primaries in visual binaries, $<$26.5% for the fraction of sub-stellar companions around secondaries in visual binaries, and an occurrence rate of $<$9.0% for giant planets and brown dwarfs around either component of visual binaries. We have combined our observations with literature measurements to astrometrically confirm, for the first time, that 20 binaries and two triple systems, which were previously known, are indeed physically bound. Finally, we discovered a third component of the binary HD~121336. The upper limits we derived are compatible with planet formation through the core accretion and the gravitational instability processes in binaries. These limits are also in line with limits found for single star and circumbinary planet search surveys.
{"title":"VIBES: Visual Binary Exoplanet survey with SPHERE","authors":"J. Hagelberg, N. Engler, C. Fontanive, S. Daemgen, S. Quanz, J. Kuhn, M. Reggiani, M. Meyer, R. Jayawardhana, V. B. I. F. T. Physics, Astrophysics, E. Zurich, Switzerland., G. Observatory, U. Geneva, Center for Space, Habitability, U. Bern, Bern, Institute of Astrophysics, K. Leuven, Celestijnlaan 200D, Leuven, Belgium, U. Michigan, A. Department, Usa, D. Astronomy, C. University, Ithaca, Ny, NasaGsfc","doi":"10.1051/0004-6361/202039173","DOIUrl":"https://doi.org/10.1051/0004-6361/202039173","url":null,"abstract":"Recent surveys indicate that planets in binary systems are more abundant than previously thought, which is in agreement with theoretical work on disc dynamics and planet formation in binaries. In order to measure the abundance and physical characteristics of wide-orbit giant exoplanets in binary systems, we have designed the 'VIsual Binary Exoplanet survey with Sphere' (VIBES) to search for planets in visual binaries. It uses the SPHERE instrument at VLT to search for planets in 23 visual binary and four visual triple systems with ages of <145 Myr and distances of <150 pc. We used the IRDIS dual-band imager on SPHERE to acquire high-contrast images of the sample targets. For each binary, the two components were observed at the same time with a coronagraph masking only the primary star. For the triple star, the tight components were treated as a single star for data reduction. This enabled us to effectively search for companions around 50 individual stars in binaries and four binaries in triples. We derived upper limits of $<$13.7% for the frequency of sub-stellar companions around primaries in visual binaries, $<$26.5% for the fraction of sub-stellar companions around secondaries in visual binaries, and an occurrence rate of $<$9.0% for giant planets and brown dwarfs around either component of visual binaries. We have combined our observations with literature measurements to astrometrically confirm, for the first time, that 20 binaries and two triple systems, which were previously known, are indeed physically bound. Finally, we discovered a third component of the binary HD~121336. The upper limits we derived are compatible with planet formation through the core accretion and the gravitational instability processes in binaries. These limits are also in line with limits found for single star and circumbinary planet search surveys.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"58 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74656851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-30DOI: 10.1051/0004-6361/202038779
N. Katyal, G. Ortenzi, J. Grenfell, L. Noack, F. Sohl, M. Godolt, A. G. Muñoz, F. Schreier, F. Wunderlich, H. Rauer
The magma ocean period was a critical phase determining how Earth atmosphere developed into habitability. However there are major uncertainties in the role of key processes such as outgassing from the planetary interior and escape of species to space that play a major role in determining the atmosphere of early Earth. We investigate the influence of outgassing of various species and escape of H$_2$ for different mantle redox states upon the composition and evolution of the atmosphere for the magma ocean period. We include an important new atmosphere-interior coupling mechanism namely the redox evolution of the mantle which strongly affects the outgassing of species. We simulate the volatile outgassing and chemical speciation at the surface for various redox states of the mantle by employing a C-H-O based chemical speciation model combined with an interior outgassing model. We then apply a line-by-line radiative transfer model to study the remote appearance of the planet in terms of the infrared emission and transmission. Finally, we use a parameterized diffusion-limited and XUV energy-driven atmospheric escape model to calculate the loss of H$_2$ to space. We have simulated the thermal emission and transmission spectra for reduced or oxidized atmospheres present during the magma ocean period of Earth. Reduced or thin atmospheres consisting of H$_2$ in abundance emit more radiation to space and have larger effective height as compared to oxidized or thick atmospheres which are abundant in H$_2$O and CO$_2$. We obtain the outgassing rates of H2 from the mantle into the atmosphere to be a factor of ten times larger than the rates of diffusion-limited escape to space. Our work presents useful insight into the development of Earth atmosphere during the magma ocean period as well as input to guide future studies discussing exoplanetary interior compositions.
{"title":"Effect of mantle oxidation state and escape upon the evolution of Earth’s magma ocean atmosphere","authors":"N. Katyal, G. Ortenzi, J. Grenfell, L. Noack, F. Sohl, M. Godolt, A. G. Muñoz, F. Schreier, F. Wunderlich, H. Rauer","doi":"10.1051/0004-6361/202038779","DOIUrl":"https://doi.org/10.1051/0004-6361/202038779","url":null,"abstract":"The magma ocean period was a critical phase determining how Earth atmosphere developed into habitability. However there are major uncertainties in the role of key processes such as outgassing from the planetary interior and escape of species to space that play a major role in determining the atmosphere of early Earth. We investigate the influence of outgassing of various species and escape of H$_2$ for different mantle redox states upon the composition and evolution of the atmosphere for the magma ocean period. We include an important new atmosphere-interior coupling mechanism namely the redox evolution of the mantle which strongly affects the outgassing of species. We simulate the volatile outgassing and chemical speciation at the surface for various redox states of the mantle by employing a C-H-O based chemical speciation model combined with an interior outgassing model. We then apply a line-by-line radiative transfer model to study the remote appearance of the planet in terms of the infrared emission and transmission. Finally, we use a parameterized diffusion-limited and XUV energy-driven atmospheric escape model to calculate the loss of H$_2$ to space. We have simulated the thermal emission and transmission spectra for reduced or oxidized atmospheres present during the magma ocean period of Earth. Reduced or thin atmospheres consisting of H$_2$ in abundance emit more radiation to space and have larger effective height as compared to oxidized or thick atmospheres which are abundant in H$_2$O and CO$_2$. We obtain the outgassing rates of H2 from the mantle into the atmosphere to be a factor of ten times larger than the rates of diffusion-limited escape to space. Our work presents useful insight into the development of Earth atmosphere during the magma ocean period as well as input to guide future studies discussing exoplanetary interior compositions.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86028094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Many discovered multiplanet systems are tightly packed. This implies that wide parameter ranges in masses and orbital elements can be dynamically unstable and ruled out. We present a case study of Kepler-23, a compact three-planet system where constraints from stability, transit timing variations (TTVs), and transit durations can be directly compared. We find that in this tightly packed system, stability can place upper limits on the masses and orbital eccentricities of the bodies that are comparable to or tighter than current state of the art methods. Specifically, stability places 68% upper limits on the orbital eccentricities of 0.09, 0.04, and 0.05 for planets $b$, $c$ and $d$, respectively. These constraints correspond to radial velocity signals $lesssim 20$ cm/s, are significantly tighter to those from transit durations, and comparable to those from TTVs. Stability also yields 68% upper limits on the masses of planets $b$, $c$ and $d$ of 2.2, 16.1, and 5.8 $M_oplus$, respectively, which were competitive with TTV constraints for the inner and outer planets. Performing this stability constrained characterization is computationally expensive with N-body integrations. We show that SPOCK, the Stability of Planetary Orbital Configurations Klassifier (Tamayo et al., 2020) is able to faithfully approximate the N-body results over 4000 times faster. We argue that such stability constrained characterization of compact systems is a challenging "needle-in-a-haystack" problem (requiring removal of 2500 unstable configurations for every stable one for our adopted priors) and we offer several practical recommendations for such stability analyses.
许多被发现的多行星系统都是紧密相连的。这意味着质量和轨道元素的大范围参数可能是动态不稳定的，并被排除在外。我们提出了一个开普勒-23的案例研究，这是一个紧凑的三行星系统，可以直接比较稳定性，凌日时间变化(TTVs)和凌日持续时间的限制。我们发现，在这个紧凑的系统中，稳定性可以为物体的质量和轨道偏心率设定上限，这些上限与当前最先进的方法相当或更严格。具体来说，稳定性排在68位% upper limits on the orbital eccentricities of 0.09, 0.04, and 0.05 for planets $b$, $c$ and $d$, respectively. These constraints correspond to radial velocity signals $lesssim 20$ cm/s, are significantly tighter to those from transit durations, and comparable to those from TTVs. Stability also yields 68% upper limits on the masses of planets $b$, $c$ and $d$ of 2.2, 16.1, and 5.8 $M_oplus$, respectively, which were competitive with TTV constraints for the inner and outer planets. Performing this stability constrained characterization is computationally expensive with N-body integrations. We show that SPOCK, the Stability of Planetary Orbital Configurations Klassifier (Tamayo et al., 2020) is able to faithfully approximate the N-body results over 4000 times faster. We argue that such stability constrained characterization of compact systems is a challenging "needle-in-a-haystack" problem (requiring removal of 2500 unstable configurations for every stable one for our adopted priors) and we offer several practical recommendations for such stability analyses.
{"title":"Stability constrained characterization of multiplanet systems","authors":"D. Tamayo, C. Gilbertson, D. Foreman-Mackey","doi":"10.1093/mnras/staa3887","DOIUrl":"https://doi.org/10.1093/mnras/staa3887","url":null,"abstract":"Many discovered multiplanet systems are tightly packed. This implies that wide parameter ranges in masses and orbital elements can be dynamically unstable and ruled out. We present a case study of Kepler-23, a compact three-planet system where constraints from stability, transit timing variations (TTVs), and transit durations can be directly compared. We find that in this tightly packed system, stability can place upper limits on the masses and orbital eccentricities of the bodies that are comparable to or tighter than current state of the art methods. Specifically, stability places 68% upper limits on the orbital eccentricities of 0.09, 0.04, and 0.05 for planets $b$, $c$ and $d$, respectively. These constraints correspond to radial velocity signals $lesssim 20$ cm/s, are significantly tighter to those from transit durations, and comparable to those from TTVs. Stability also yields 68% upper limits on the masses of planets $b$, $c$ and $d$ of 2.2, 16.1, and 5.8 $M_oplus$, respectively, which were competitive with TTV constraints for the inner and outer planets. Performing this stability constrained characterization is computationally expensive with N-body integrations. We show that SPOCK, the Stability of Planetary Orbital Configurations Klassifier (Tamayo et al., 2020) is able to faithfully approximate the N-body results over 4000 times faster. We argue that such stability constrained characterization of compact systems is a challenging \"needle-in-a-haystack\" problem (requiring removal of 2500 unstable configurations for every stable one for our adopted priors) and we offer several practical recommendations for such stability analyses.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"63 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91287798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-21DOI: 10.1142/s0129183121500285
V. Geroyannis
In the so-called "global polytropic model", we assume planetary systems in hydrostatic equilibrium and solve the Lane--Emden equation in the complex plane. We thus find polytropic spherical shells providing hosting orbits to planets. On the basis of this model, we develop a numerical method which has three versions. In its three-dimensional version, the method is effective for systems with substantial uncertainties in the observed host star radius, and in the orbit of a particular planet (compared to the uncertainties in the orbits of the other planets); the method uses as fixed entry values the observed orbits of the remaining planets. In its two-dimensional version, the method is effective for systems with substantial uncertainty in the host star radius; in this case, the method uses as fixed entry values the observed orbits of the planets. The one-dimensional version was previously developed and applied to several systems; in this version, the observed values of the host star radius and of the planetary orbits are taken as fixed entry values. Our method can compute optimum values for the polytropic index of the global polytropic model which simulates the exoplanetary system, for the orbits of the planets, and (excluding the one-dimensional version) for the host star radius.
{"title":"A numerical method for computing optimum radii of host stars and orbits of planets, with application to Kepler-11, Kepler-90, Kepler-215, HD 10180, HD 34445 and TRAPPIST-1","authors":"V. Geroyannis","doi":"10.1142/s0129183121500285","DOIUrl":"https://doi.org/10.1142/s0129183121500285","url":null,"abstract":"In the so-called \"global polytropic model\", we assume planetary systems in hydrostatic equilibrium and solve the Lane--Emden equation in the complex plane. We thus find polytropic spherical shells providing hosting orbits to planets. On the basis of this model, we develop a numerical method which has three versions. In its three-dimensional version, the method is effective for systems with substantial uncertainties in the observed host star radius, and in the orbit of a particular planet (compared to the uncertainties in the orbits of the other planets); the method uses as fixed entry values the observed orbits of the remaining planets. In its two-dimensional version, the method is effective for systems with substantial uncertainty in the host star radius; in this case, the method uses as fixed entry values the observed orbits of the planets. The one-dimensional version was previously developed and applied to several systems; in this version, the observed values of the host star radius and of the planetary orbits are taken as fixed entry values. Our method can compute optimum values for the polytropic index of the global polytropic model which simulates the exoplanetary system, for the orbits of the planets, and (excluding the one-dimensional version) for the host star radius.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"58 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74342938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-21DOI: 10.1051/0004-6361/202038367
J. Haldemann, Y. Alibert, C. Mordasini, W. Benz
Water is one of the key chemical elements in planetary structure modelling. Due to its complex phase diagram, equations of state cover often only parts of the pressure - temperature space needed in planetary modelling. We construct an equation of state of H$_2$O spanning a very wide range from 0.1 Pa to 400 TPa and 150 K to $10^{5}$ K, which can be used to model the interior of planets. We combine equations of state valid in localised regions to form a continuous equation of state spanning over said pressure and temperature range. We provide tabulated values for the most important thermodynamic quantities, i.e., density, adiabatic temperature gradient, entropy, internal energy and bulk speed of sound of water over this pressure and temperature range. For better usability we also calculated density - temperature and density - internal energy grids. We discuss further the impact of this equation of state on the mass radius relation of planets compared to other popular equation of states like ANEOS and QEOS. AQUA is a combination of existing equation of state useful for planetary models. We show that AQUA is in most regions a thermodynamic consistent description of water. At pressures above 10 GPa AQUA predicts systematic larger densities than ANEOS or QEOS. A feature which was already present in a previously proposed equation of state, which is the main underlying equation of this work. We show that the choice of the equation of state can have a large impact on the mass-radius relation, which highlights the importance of future developments in the field of equation of states and regarding experimental data of water at high pressures.
{"title":"AQUA: a collection of H2O equations of state for planetary models","authors":"J. Haldemann, Y. Alibert, C. Mordasini, W. Benz","doi":"10.1051/0004-6361/202038367","DOIUrl":"https://doi.org/10.1051/0004-6361/202038367","url":null,"abstract":"Water is one of the key chemical elements in planetary structure modelling. Due to its complex phase diagram, equations of state cover often only parts of the pressure - temperature space needed in planetary modelling. We construct an equation of state of H$_2$O spanning a very wide range from 0.1 Pa to 400 TPa and 150 K to $10^{5}$ K, which can be used to model the interior of planets. We combine equations of state valid in localised regions to form a continuous equation of state spanning over said pressure and temperature range. We provide tabulated values for the most important thermodynamic quantities, i.e., density, adiabatic temperature gradient, entropy, internal energy and bulk speed of sound of water over this pressure and temperature range. For better usability we also calculated density - temperature and density - internal energy grids. We discuss further the impact of this equation of state on the mass radius relation of planets compared to other popular equation of states like ANEOS and QEOS. AQUA is a combination of existing equation of state useful for planetary models. We show that AQUA is in most regions a thermodynamic consistent description of water. At pressures above 10 GPa AQUA predicts systematic larger densities than ANEOS or QEOS. A feature which was already present in a previously proposed equation of state, which is the main underlying equation of this work. We show that the choice of the equation of state can have a large impact on the mass-radius relation, which highlights the importance of future developments in the field of equation of states and regarding experimental data of water at high pressures.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"84 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83894668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nearly 15 years of radial velocity (RV) monitoring and direct imaging (DI) enabled the detection oftwo giant planets orbiting the young, nearby star β Pictoris. The δ Scuti pulsations of the star, overwhelming planetary signals, need however to be carefully suppress. In this talk, we propose a new and independent analysis of the system, making use of all available data, including photometric light curve from the ground and space, long term RV and DI monitoring. We demonstrate how all data can be consistently modelled in a Bayesian framework. We show how modern and physically motivated kernels for Gaussian Process can effectively model complex stellar activity. Using further carefull statistical treatment of the data to extend the monitoring, we detect both planets from RV data only for the first time. To characterize the system more accurately, we also perform a joint fit of all available relative astrometry and RV data. We provide precise orbital parameters and discuss the whole system architecture. The inferred dynamical mass measurements for both planets are also compared to mass-luminosity evolutionary tracks. This work opens the path towards a precise characterization of young planetary systems combing photometry, spectroscopy, and astrometry.
{"title":"New Dynamical Mass Estimates of the beta Pictoris Planetary System Through Gaussian Process Stellar Activity Modelling","authors":"T. Vandal, J. Rameau, R. Doyon","doi":"10.5194/epsc2020-954","DOIUrl":"https://doi.org/10.5194/epsc2020-954","url":null,"abstract":"<p>Nearly 15 years of radial velocity (RV) monitoring and direct imaging (DI) enabled the detection oftwo giant planets orbiting the young, nearby star β Pictoris. The δ Scuti pulsations of the star, overwhelming planetary signals, need however to be carefully suppress. In this talk, we propose a new and independent analysis of the system, making use of all available data, including photometric light curve from the ground and space, long term RV and DI monitoring. We demonstrate how all data can be consistently modelled in a Bayesian framework. We show how modern and physically motivated kernels for Gaussian Process can effectively model complex stellar activity. Using further carefull statistical treatment of the data to extend the monitoring, we detect both planets from RV data only for the first time. To characterize the system more accurately, we also perform a joint fit of <br />all available relative astrometry and RV data. We provide precise orbital parameters and discuss the whole system architecture. The inferred dynamical mass measurements for both planets are also compared to mass-luminosity evolutionary tracks. This work opens the path towards a precise characterization of young planetary systems combing photometry, spectroscopy, and astrometry.</p>","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"87 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76508758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-06DOI: 10.1016/J.EPSL.2021.116854
Zheng Liu, Y. Liu, L. Pan, Jiannan Zhao, E. Kite, Yuchun Wu, Yongliao Zou
{"title":"Inverted channel belts and floodplain clays to the East of Tempe Terra, Mars: Implications for persistent fluvial activity on early Mars","authors":"Zheng Liu, Y. Liu, L. Pan, Jiannan Zhao, E. Kite, Yuchun Wu, Yongliao Zou","doi":"10.1016/J.EPSL.2021.116854","DOIUrl":"https://doi.org/10.1016/J.EPSL.2021.116854","url":null,"abstract":"","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87524775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：