arXiv: Earth and Planetary Astrophysics最新文献

{"title":"Thermal evolution of protoplanetary disks: from β-cooling to decoupled gas and dust temperatures","authors":"Eduard I. Vorobyov Ryoki Matsukoba, K. Omukai, M. G. U. O. Vienna, Department of Astrophysics, Vienna, 1180, Austria, Ural Federal University, 51 Lenin Str., 620051 Ekaterinburg, Russia., A. Institute, G. S. O. Sciences, T. University, Aoba, Sendai, Miyagi 980-8578, Japan.","doi":"10.1051/0004-6361/202037841","DOIUrl":"https://doi.org/10.1051/0004-6361/202037841","url":null,"abstract":"Aims: We explore the long-term evolution of young protoplanetary disks with different approaches to computing the thermal structure determined by various cooling and heating processes in the disk and its surroundings. Methods: Numerical hydrodynamics simulations in the thin-disk limit were complemented with three thermal evolution schemes: a simplified $beta$-cooling approach with and without irradiation, in which the rate of disk cooling is proportional to the local dynamical time, a fiducial model with equal dust and gas temperatures calculated taking viscous heating, irradiation, and radiative cooling into account, and also a more sophisticated approach allowing decoupled dust and gas temperatures. Results: We found that the gas temperature may significantly exceed that of dust in the outer regions of young disks thanks to additional compressional heating caused by the infalling envelope material in the early stages of disk evolution and slow collisional exchange of energy between gas and dust in low-density disk regions. The outer envelope however shows an inverse trend with the gas temperatures dropping below that of dust. The global disk evolution is only weakly sensitive to temperature decoupling. Nevertheless, separate dust and gas temperatures may affect the chemical composition, dust evolution, and disk mass estimates. Constant-$beta$ models without stellar and background irradiation fail to reproduce the disk evolution with more sophisticated thermal schemes because of intrinsically variable nature of the $beta$-parameter. Constant-$beta$ models with irradiation can better match the dynamical and thermal evolution, but the agreement is still incomplete. Conclusions: Models allowing separate dust and gas temperatures are needed when emphasis is placed on the chemical or dust evolution in protoplanetary disks, particularly in sub-solar metallicity environments.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84874910","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}

{"title":"Planet-star interactions with precise transit timing. II. The radial-velocity tides and a tighter constraint on the orbital decay rate in the WASP-18 system","authors":"G. Maciejewski, H. Knutson, A. Howard, H. Isaacson, E. Fernández-Lajús, R. Sisto, C. Migaszewski","doi":"10.32023/0001-5237/70.1.1","DOIUrl":"https://doi.org/10.32023/0001-5237/70.1.1","url":null,"abstract":"From its discovery, the WASP-18 system with its massive transiting planet on a tight orbit was identified as a unique laboratory for studies on tidal planet-star interactions. In an analysis of Doppler data, which include five new measurements obtained with the HIRES/Keck-I instrument between 2012 and 2018, we show that the radial velocity signal of the photosphere following the planetary tidal potential can be distilled for the host star. Its amplitude is in agreement with both theoretical predictions of the equilibrium tide approximation and an ellipsoidal modulation observed in an orbital phase curve. Assuming a circular orbit, we refine system parameters using photometric time series from TESS. With a new ground-based photometric observation, we extend the span of transit timing observations to 28 years in order to probe the rate of the orbital period shortening. Since we found no departure from a constant-period model, we conclude that the modified tidal quality parameter of the host star must be greater than 3.9x10^6 with 95% confidence. This result is in line with conclusions drawn from studies of the population of hot Jupiters, predicting that the efficiency of tidal dissipation is 1 or 2 orders of magnitude weaker. As the WASP-18 system is one of the prime candidates for detection of orbital decay, further timing observations are expected to push the boundaries of our knowledge on stellar interiors.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"68 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87739550","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}

{"title":"Near-Infrared Transit Photometry of Extra-Solar Planet HAT-P-54b","authors":"H. Tabata, Y. Itoh","doi":"10.4236/ijaa.2020.102007","DOIUrl":"https://doi.org/10.4236/ijaa.2020.102007","url":null,"abstract":"The results of near-infrared photometric observations of a transit event of an extrasolar planet HAT-P-54b are presented herein. Precise near-infrared photometry was carried out using the Nayuta 2 m telescope at Nishi-Harima Astronomical Observatory, Japan and Nishi-harima Infrared Camera (NIC). 170 J-, H-, and Ks-band images were taken in each band in 196 minutes. The flux of the planetary system was observed to decrease during the transit event. While the the Ks-band transit depth is similar to that in the r-band, the J- and H-band transits are deeper than those in the Ks-band. We constructed simple models of the planetary atmosphere and found that the observed transit depths are well reproduced by inflated atmosphere containing H2S molecule.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"45 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88099493","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}

{"title":"The habitability of large elliptical galaxies","authors":"D. Whitmire","doi":"10.1093/mnras/staa957","DOIUrl":"https://doi.org/10.1093/mnras/staa957","url":null,"abstract":"Based on numbers of stars, supernova rates, and metallicity, a prior study (Dayal et al. 2015) concluded that large elliptical galaxies contain up to 10,000 times more habitable planets than the Milky Way and are thus the \"cradles of life\". Using the results of their model and taking into account galactic number distributions and supernova rates I argue here that this result constitutes a violation of the Principle of Mediocrity as applied to the reference class of all extant technological species. Assuming that we are a typical technological species in the attribute of inhabiting a relatively large disk-dominated galaxy, I outline two hypotheses that could significantly limit the habitability of large elliptical galaxies: (1) massive galactic sterilization events associated with quasar/AGN activity and starburst supernovae that occurred when the antecedents of today's large elliptical galaxies were much more compact; and (2) the probability of habitable planet formation in large elliptical galaxies may be small since a disproportionately larger number of gaseous planets are expected to form as a result of the generally higher metallicity in large elliptical galaxies. Consequently, fewer habitable planets will accrete if the gaseous planets inward migrations are sufficiently slow. The sterilization events of Hypothesis (1) occurred at earlier epochs (z $geq$ 1) and so they must be effectively permanent, implying two possible scenarios regarding the origin and evolution of life. In connection with one of these scenarios, independent applications of the Principle of Mediocrity suggest that M-dwarf stars are not significant hosts of technological life.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90216047","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}

{"title":"The most common habitable planets – II. Salty oceans in low-mass habitable planets and global climate evolution","authors":"R. Pinotti, G. P. D. Mello","doi":"10.1093/mnras/staa3260","DOIUrl":"https://doi.org/10.1093/mnras/staa3260","url":null,"abstract":"The available models of global climate evolution in habitable earthlike planets do not consider the effect of salt content in oceans, which affects water evaporation. Two distinct categories of such planets are considered in this work: planets with deep oceans, but with intrinsically high salinities due to the weaker salt removal process by hydrothermal vents; and planets with shallow oceans, where the increase in salt content and decrease in ocean area during the onset of glaciation cause a measurable negative feedback on perturbations, helping delay the onset of ice ages. We developed a toy climate model of a habitable planet on the verge of an ice age, using a range of initial salt concentrations. For planets with deep oceans and high salinity we find a considerable decrease in land ice sheet growth rate, up to ~ 23% considering the maximum salinity range. For planets with shallow oceans, the effect of intrinsic high salinity previously modelled is reinforced by the negative feedback, to the point of effectively terminating the land ice sheet growth rate during the time-scale of the simulations. We also investigate the application of this model to the putative ocean of early Mars, and find that the results lie in between the two categories. We conclude that this new phenomenon, which can be viewed as an abiotic self-regulation process against ice ages, should be taken into account in studies of habitable planets smaller and drier than the Earth, which may well represent the bulk of habitable planets.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76045918","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}

{"title":"Volatile evolution and atmospheres of Trans-Neptunian objects","authors":"L. Young, F. Braga-Ribas, Robert E. Johnson","doi":"10.1016/B978-0-12-816490-7.00006-0","DOIUrl":"https://doi.org/10.1016/B978-0-12-816490-7.00006-0","url":null,"abstract":"","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81317861","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}

{"title":"Modelling the He I triplet absorption at 10 830 Å in the atmosphere of HD 209458 b","authors":"M. Lamp'on, M. L'opez-Puertas, L. Lara, A. S'anchez-L'opez, M. Salz, S. Czesla, J. Sanz-Forcada, K. Molaverdikhani, F. J. Alonso-Floriano, L. Nortmann, J. Caballero, F. Bauer, E. Pall'e, D. Montes, A. Quirrenbach, E. Nagel, I. Ribas, A. Reiners, P. Amado","doi":"10.1051/0004-6361/201937175","DOIUrl":"https://doi.org/10.1051/0004-6361/201937175","url":null,"abstract":"HD 209458b is an exoplanet with an upper atmosphere undergoing blow-off escape that has mainly been studied using measurements of the Ly-alpha absorption. Recently, high-resolution measurements of absorption in the He I triplet line at 10830 angstroms of several exoplanets (including HD 209458b) have been reported, creating a new opportunity to probe escaping atmospheres. We aim to better understand the atmospheric regions of HD 209458b from where the escape originates. We developed a 1D hydrodynamic model with spherical symmetry for the HD 209458 b thermosphere coupled with a non-local thermodynamic model for the population of the He triplet state. In addition, we performed high-resolution radiative transfer calculations of synthetic spectra for the He triplet lines and compared them with the measured absorption spectrum in order to retrieve information about the atmospheric parameters. We find that the measured spectrum constrains the [H]/[H$^{+}$] transition altitude occurring in the range of 1.2 to 1.9Rp. H is almost fully ionised at altitudes above 2.9Rp. We also find that the X-ray and EUV absorption takes place at effective radii from 1.16 to 1.30Rp, and that the He triplet peak density occurs at altitudes from 1.04 to 1.60Rp. Additionally, the averaged mmw is confined to the 0.61-0.73 g/mole interval, and the thermospheric H/He ratio should be larger than 90/10, and most likely approximately 98/2. We also provide a one-to-one relationship between mass-loss rate and temperature. Based on the energy-limited escape approach and assuming heating efficiencies of 0.1-0.2, we find a mass-loss rate in the range of (0.42-1.00)$times 10^{11}$ g/s and a corresponding temperature range of 7125 to 8125K. The analysis of the measured He triplet absorption spectrum significantly constrains the thermospheric structure of HD 209458b and advances our knowledge of its escaping atmosphere.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89509151","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}

{"title":"Doppler tomographic measurement of the nodal precession of WASP-33b","authors":"N. Watanabe, N. Narita, Marshall C. Johnson","doi":"10.1093/pasj/psz140","DOIUrl":"https://doi.org/10.1093/pasj/psz140","url":null,"abstract":"WASP-33b is a retrograde hot Jupiter with a period of 1.2 days orbiting around a rapidly rotating and pulsating A-type star. A previous study found that the transit chord of WASP-33b had changed slightly from 2008 to 2014 based on Doppler tomographic measurements. They attributed the change to orbital precession caused by the non-zero oblateness of the host star and the misaligned orbit. We aim to confirm and more precisely model the precession behavior using additional Doppler tomographic data of WASP-33b obtained with the High Dispersion Spectrograph on the 8.2m Subaru telescope in 2011, as well as the datasets used in the previous study. Using equations of a long-term orbital precession, we constrain the stellar gravitational quadrupole moment $J_{2}=(9.14pm 0.51)times 10^{-5}$ and the angle between the stellar spin axis and the line of sight $i_{star}=96^{+10}_{-14}$ deg. These values update that the host star is more spherical and viewed more equator than the previous study. We also estimate that the precession period is $sim$840 years. We also find that the precession amplitude of WASP-33b is $sim$67 deg and WASP-33b transits in front of the host star for only $sim$20% of the whole precession period.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88445948","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}

{"title":"Three short-period Jupiters from TESS","authors":"L. Nielsen, R. Brahm, F. Bouchy, N. Espinoza, O. Turner, S. Rappaport, L. Pearce, G. Ricker, R. Vanderspek, D. Latham, S. Seager, J. Winn, J. Jenkins, J. Acton, G. Bakos, T. Barclay, K. Barkaoui, W. Bhatti, C. Briceño, E. Bryant, M. Burleigh, D. Ciardi, K. Collins, K. Collins, B. Cooke, Z. Csubry, L. D. Santos, P. Eigmuller, M. Fausnaugh, T. Gan, M. Gillon, M. Goad, N. Guerrero, J. Hagelberg, R. Hart, T. Henning, C. Huang, E. Jehin, J. Jenkins, A. Jordán, J. Kielkopf, D. Kossakowski, B. Lavie, N. Law, M. Lendl, J. D. Leon, C. Lovis, A. Mann, M. Marmier, J. McCormac, M. Mori, M. Moyano, N. Narita, D. Osip, J. Otegi, F. Pepe, F. Pozuelos, L. Raynard, H. Relles, P. Sarkis, D. Ségransan, J. Seidel, Avi Shporer, M. Stalport, C. Stockdale, V. Suc, M. Tamura, T. Tan, R. Tilbrook, E. Ting, T. Trifonov, S. Udry, A. Vanderburg, P. Wheatley, Geof Wingham, Z. Zhan, C. Ziegler","doi":"10.1051/0004-6361/202037941","DOIUrl":"https://doi.org/10.1051/0004-6361/202037941","url":null,"abstract":"We report the confirmation and mass determination of three hot Jupiters discovered by the Transiting Exoplanet Survey Satellite (TESS) mission: HIP 65Ab (TOI-129, TIC-201248411) is an ultra-short-period Jupiter orbiting a bright (V=11.1 mag) K4-dwarf every 0.98 days. It is a massive 3.213 +/- 0.078 Mjup planet in a grazing transit configuration with an impact parameter of b = 1.17 +0.10/-0.08. As a result the radius is poorly constrained, 2.03 +0.61/-0.49 Rjup. The planet's distance to its host star is less than twice the separation at which it would be destroyed by Roche lobe overflow. It is expected to spiral into HIP 65A on a timescale ranging from 80 Myr to a few gigayears, assuming a reduced tidal dissipation quality factor of Qs' = 10^7 - 10^9. We performed a full phase-curve analysis of the TESS data and detected both illumination- and ellipsoidal variations as well as Doppler boosting. HIP 65A is part of a binary stellar system, with HIP 65B separated by 269 AU (3.95 arcsec on sky). TOI-157b (TIC 140691463) is a typical hot Jupiter with a mass of 1.18 +/- 0.13 Mjup and a radius of 1.29 +/- 0.02 Rjup. It has a period of 2.08 days, which corresponds to a separation of just 0.03 AU. This makes TOI-157 an interesting system, as the host star is an evolved G9 sub-giant star (V=12.7). TOI-169b (TIC 183120439) is a bloated Jupiter orbiting a V=12.4 G-type star. It has a mass of 0.79 +/- 0.06 Mjup and a radius of 1.09 +0.08/-0.05 Rjup. Despite having the longest orbital period (P = 2.26 days) of the three planets, TOI-169b receives the most irradiation and is situated on the edge of the Neptune desert. All three host stars are metal rich with [Fe/H] ranging from 0.18 - 0.24.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"49 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80863379","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}

{"title":"TNOs are Cool! A Survey of the transneptunian Region XV. Physical characteristics of 23 resonant transneptunian and scattered disk objects","authors":"A. Farkas-Tak'acs, C. Kiss, E. Vilenius, G. Marton, T. Muller, Michael Mommert, J. Stansberry, E. Lellouch, P. Lacerda, A. P'al","doi":"10.1051/0004-6361/201936183","DOIUrl":"https://doi.org/10.1051/0004-6361/201936183","url":null,"abstract":"The goal of this work is to determine the physical characteristics of resonant, detached and scattered disk objects in the transneptunian region, observed mainly in the framework of the \"TNOs are Cool!\" Herschel Open Time Key Program. Based on thermal emission measurements with the Herschel/PACS and Spitzer/MIPS instruments we determine size, albedo, and surface thermal properties for 23 objects using radiometric modelling techniques. This is the first analysis in which the physical properties of objects in the outer resonances are determined for a notable sample. In addition to the results for individual objects, we have compared these characteristics with the bulk properties of other populations of the transneptunian region. The newly analyzed objects show a large variety of beaming factors, indicating a diversity of thermal properties, and in general, they follow the albedo-colour clustering identified earlier for Kuiper belt objects and Centaurs, further strengthening the evidence for a compositional discontinuity in the young Solar System.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81414835","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}