Pub Date : 2019-06-26DOI: 10.5303/JKAS.2020.53.1.9
A. Gould, Y. Ryu, S. Novati, W. Zang, M. Albrow, Sun-Ju Chung, C. Han, K. Hwang, Y. Jung, I. Shin, Y. Shvartzvald, J. Yee, S. Cha, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Kim, Chung-Uk Lee, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, R. Pogge, C. Beichman, G. Bryden, S. Carey, B. Gaudi, C. Henderson, Wei Zhu, P. Fouqu'e, M. Penny, A. Petric, T. Burdullis, S. Mao
At $q=1.81pm 0.20 times 10^{-5}$, KMT-2018-BLG-0029Lb has the lowest planet-host mass ratio $q$ of any microlensing planet to date by more than a factor of two. Hence, it is the first planet that probes below the apparent "pile-up" at $q=5$--10 $times 10^{-5}$. The event was observed by {it Spitzer}, yielding a microlens-parallax $pi_{rm E}$ measurement. Combined with a measurement of the Einstein radius $theta_{rm E}$ from finite-source effects during the caustic crossings, these measurements imply masses of the host $M_{rm host}=1.14^{+0.10}_{-0.12}, M_odot$ and planet $M_{rm planet} = 7.59^{+0.75}_{-0.69},M_oplus$, system distance $D_L = 3.38^{+0.22}_{-0.26},,{rm kpc}$ and projected separation $a_perp = 4.27^{+0.21}_{-0.23},{rm au}$. The blended light, which is substantially brighter than the microlensed source, is plausibly due to the lens and could be observed at high resolution immediately.
{"title":"KMT-2018-BLG-0029Lb: A Very Low Mass-Ratio Spitzer Microlens Planet","authors":"A. Gould, Y. Ryu, S. Novati, W. Zang, M. Albrow, Sun-Ju Chung, C. Han, K. Hwang, Y. Jung, I. Shin, Y. Shvartzvald, J. Yee, S. Cha, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Kim, Chung-Uk Lee, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, R. Pogge, C. Beichman, G. Bryden, S. Carey, B. Gaudi, C. Henderson, Wei Zhu, P. Fouqu'e, M. Penny, A. Petric, T. Burdullis, S. Mao","doi":"10.5303/JKAS.2020.53.1.9","DOIUrl":"https://doi.org/10.5303/JKAS.2020.53.1.9","url":null,"abstract":"At $q=1.81pm 0.20 times 10^{-5}$, KMT-2018-BLG-0029Lb has the lowest planet-host mass ratio $q$ of any microlensing planet to date by more than a factor of two. Hence, it is the first planet that probes below the apparent \"pile-up\" at $q=5$--10 $times 10^{-5}$. The event was observed by {it Spitzer}, yielding a microlens-parallax $pi_{rm E}$ measurement. Combined with a measurement of the Einstein radius $theta_{rm E}$ from finite-source effects during the caustic crossings, these measurements imply masses of the host $M_{rm host}=1.14^{+0.10}_{-0.12}, M_odot$ and planet $M_{rm planet} = 7.59^{+0.75}_{-0.69},M_oplus$, system distance $D_L = 3.38^{+0.22}_{-0.26},,{rm kpc}$ and projected separation $a_perp = 4.27^{+0.21}_{-0.23},{rm au}$. The blended light, which is substantially brighter than the microlensed source, is plausibly due to the lens and could be observed at high resolution immediately.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81427841","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 : 2019-05-21DOI: 10.5303/JKAS.2019.52.3.71
Y. P. Bach, M. Ishiguro, Sunho Jin, Hongu Yang, H. Moon, Young‐Jun Choi, Y. JeongAhn, Myung-Jin Kim, S. Kwak
We derive the geometric albedo of a near-Earth asteroid, (4179) Toutatis, to investigate its surface physical conditions. The asteroid has been studied rigorously not only via ground-based photometric, spectrometric, polarimetric, and radar observations but also via textit{in situ} observation by the Chinese Chang'e-2 space probe; however, its geometric albedo is not well understood. We conducted V-band photometric observations when the asteroid was at opposition in April 2018 using the three telescopes in the southern hemisphere that compose the Korea Microlensing Telescope Network (KMTNet). The observed time-variable cross section was corrected using the radar shape model. We find that Toutatis has a geometric albedo $p_mathrm{V} = 0.185^{+0.045}_{-0.039} $, which is typical of S-type asteroids. We compare the geometric albedo with archival polarimetric data and further find that the polarimetric slope--albedo law provides a reliable estimate for the albedo of this S-type asteroid. The thermal infrared observation also produced similar results if the size of the asteroid is updated to match the results from Chang'e-2. We conjecture that the surface of Toutatis is covered with grains smaller than that of the near-Sun asteroids including (1566) Icarus and (3200) Phaethon.
{"title":"The Geometric Albedo of (4179) Toutatis Estimated from KMTNet DEEP-South Observations","authors":"Y. P. Bach, M. Ishiguro, Sunho Jin, Hongu Yang, H. Moon, Young‐Jun Choi, Y. JeongAhn, Myung-Jin Kim, S. Kwak","doi":"10.5303/JKAS.2019.52.3.71","DOIUrl":"https://doi.org/10.5303/JKAS.2019.52.3.71","url":null,"abstract":"We derive the geometric albedo of a near-Earth asteroid, (4179) Toutatis, to investigate its surface physical conditions. The asteroid has been studied rigorously not only via ground-based photometric, spectrometric, polarimetric, and radar observations but also via textit{in situ} observation by the Chinese Chang'e-2 space probe; however, its geometric albedo is not well understood. We conducted V-band photometric observations when the asteroid was at opposition in April 2018 using the three telescopes in the southern hemisphere that compose the Korea Microlensing Telescope Network (KMTNet). The observed time-variable cross section was corrected using the radar shape model. We find that Toutatis has a geometric albedo $p_mathrm{V} = 0.185^{+0.045}_{-0.039} $, which is typical of S-type asteroids. We compare the geometric albedo with archival polarimetric data and further find that the polarimetric slope--albedo law provides a reliable estimate for the albedo of this S-type asteroid. The thermal infrared observation also produced similar results if the size of the asteroid is updated to match the results from Chang'e-2. We conjecture that the surface of Toutatis is covered with grains smaller than that of the near-Sun asteroids including (1566) Icarus and (3200) Phaethon.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83139944","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 : 2019-05-16DOI: 10.5303/JKAS.2019.52.4.121
A. Gould
I investigate the origin of arc degeneracies in satellite microlens parallax pi_E measurements with only late time data, e.g., t > t0 + t_E as seen from the satellite. I show that these are due to partial overlap of a series of osculating, exactly circular, degeneracies in the pi_E plane, each from a single measurement. In events with somewhat earlier data, these long arcs break up into two arclets, or (with even earlier data) two points, because these earlier measurements give rise to intersecting rather than osculating circles. The two arclets (or points) then constitute one pair of degeneracies in the well-known four-fold degeneracy of space-based microlens parallax. Using this framework of intersecting circles, I show that next-generation microlens satellite experiments could yield good pi_E determinations with only about five measurements per event, i.e., about 30 observations per day to monitor 1500 events per year. This could plausibly be done with a small (hence cheap, in the spirit of Gould & Yee 2012) satellite telescope, e.g., 20 cm.
{"title":"Osculating Versus Intersecting Circles in Space-Based Microlens Parallax Degeneracies","authors":"A. Gould","doi":"10.5303/JKAS.2019.52.4.121","DOIUrl":"https://doi.org/10.5303/JKAS.2019.52.4.121","url":null,"abstract":"I investigate the origin of arc degeneracies in satellite microlens parallax pi_E measurements with only late time data, e.g., t > t0 + t_E as seen from the satellite. I show that these are due to partial overlap of a series of osculating, exactly circular, degeneracies in the pi_E plane, each from a single measurement. In events with somewhat earlier data, these long arcs break up into two arclets, or (with even earlier data) two points, because these earlier measurements give rise to intersecting rather than osculating circles. The two arclets (or points) then constitute one pair of degeneracies in the well-known four-fold degeneracy of space-based microlens parallax. Using this framework of intersecting circles, I show that next-generation microlens satellite experiments could yield good pi_E determinations with only about five measurements per event, i.e., about 30 observations per day to monitor 1500 events per year. This could plausibly be done with a small (hence cheap, in the spirit of Gould & Yee 2012) satellite telescope, e.g., 20 cm.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82073726","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 : 2019-04-24DOI: 10.1007/978-3-319-55333-7_79
M. Deleuil, M. Fridlund
{"title":"CoRoT: The first space-based transit survey to explore the close-in planet population","authors":"M. Deleuil, M. Fridlund","doi":"10.1007/978-3-319-55333-7_79","DOIUrl":"https://doi.org/10.1007/978-3-319-55333-7_79","url":null,"abstract":"","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"26 3 1","pages":"1135-1158"},"PeriodicalIF":0.0,"publicationDate":"2019-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78333795","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}
D. Kao, M. Gacesa, R. Wentzcovitch, S. Domagal‐Goldman, R. Kopparapu, S. Klippenstein, S. Charnley, W. Henning, J. Renaud, P. Romani, Yuni Lee, C. Nixon, K. Jackson, M. Cordiner, N. Lombardo, S. Wieman, V. Airapetian, V. Allen, D. Pidhorodetska, E. Kohler, J. Moses, T. Livengood, D. N. Simkus, N. Planavsky, C. Dong, D. Yuen, A. Berg, A. Pavlov, J. Fortney
Several of NASA missions (TESS, JWST, WFIRST, etc.) and mission concepts (LUVOIR, HabEx, and OST) emphasize the exploration and characterization of exoplanets, and the study of the interstellar medium. We anticipate that a much broader set of chemical environments exists on exoplanets, necessitating data from a correspondingly broader set of chemical reactions. Similarly, the conditions that exist in astrophysical environments are very different from those traditionally probed in laboratory chemical kinetics studies. These are areas where quantum mechanical theory, applied to important reactions via well-validated chemical kinetics models, can fill a critical knowledge gap. Quantum chemical calculations are also introduced to study interior of planets, photochemical escape, and many critical chemical pathways (e.g. prebiotic environments, contaminations, etc.) After years of development of the relevant quantum chemical theories and significant advances in computational power, quantum chemical simulations have currently matured enough to describe real systems with an accuracy that competes with experiments. These approaches, therefore, have become the best possible alternative in many circumstances where performing experiments is too difficult, too expensive, or too dangerous, or simply not possible. In this white paper, several existing quantum chemical studies supporting exoplanetary science, planetary astronomy, and astrophysics are described, and the potential positive impacts of improved models associated with scientific goals of missions are addressed. In the end, a few recommendations from the scientific community to strengthen related research efforts at NASA are provided.
{"title":"Impacts of Quantum Chemistry Calculations on Exoplanetary Science, Planetary Astronomy, and Astrophysics","authors":"D. Kao, M. Gacesa, R. Wentzcovitch, S. Domagal‐Goldman, R. Kopparapu, S. Klippenstein, S. Charnley, W. Henning, J. Renaud, P. Romani, Yuni Lee, C. Nixon, K. Jackson, M. Cordiner, N. Lombardo, S. Wieman, V. Airapetian, V. Allen, D. Pidhorodetska, E. Kohler, J. Moses, T. Livengood, D. N. Simkus, N. Planavsky, C. Dong, D. Yuen, A. Berg, A. Pavlov, J. Fortney","doi":"10.13016/M2XSLB-LAEW","DOIUrl":"https://doi.org/10.13016/M2XSLB-LAEW","url":null,"abstract":"Several of NASA missions (TESS, JWST, WFIRST, etc.) and mission concepts (LUVOIR, HabEx, and OST) emphasize the exploration and characterization of exoplanets, and the study of the interstellar medium. We anticipate that a much broader set of chemical environments exists on exoplanets, necessitating data from a correspondingly broader set of chemical reactions. Similarly, the conditions that exist in astrophysical environments are very different from those traditionally probed in laboratory chemical kinetics studies. These are areas where quantum mechanical theory, applied to important reactions via well-validated chemical kinetics models, can fill a critical knowledge gap. Quantum chemical calculations are also introduced to study interior of planets, photochemical escape, and many critical chemical pathways (e.g. prebiotic environments, contaminations, etc.) After years of development of the relevant quantum chemical theories and significant advances in computational power, quantum chemical simulations have currently matured enough to describe real systems with an accuracy that competes with experiments. These approaches, therefore, have become the best possible alternative in many circumstances where performing experiments is too difficult, too expensive, or too dangerous, or simply not possible. In this white paper, several existing quantum chemical studies supporting exoplanetary science, planetary astronomy, and astrophysics are described, and the potential positive impacts of improved models associated with scientific goals of missions are addressed. In the end, a few recommendations from the scientific community to strengthen related research efforts at NASA are provided.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"36 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72588661","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 : 2019-04-05DOI: 10.1016/B978-0-12-816490-7.00002-3
A. Morbidelli, D. Nesvorný
{"title":"Kuiper belt: Formation and evolution","authors":"A. Morbidelli, D. Nesvorný","doi":"10.1016/B978-0-12-816490-7.00002-3","DOIUrl":"https://doi.org/10.1016/B978-0-12-816490-7.00002-3","url":null,"abstract":"","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"68 1","pages":"25-59"},"PeriodicalIF":0.0,"publicationDate":"2019-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73751965","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}
D. Bennett, R. Akeson, Y. Alibert, Jay Anderson, E. Bachelet, J. Beaulieu, A. Bellini, A. Bhattacharya, A. Boss, V. Bozza, S. Bryson, D. Buzasi, S. Novati, J. Christiansen, S. Domagal‐Goldman, M. Endl, B. Fulton, C. Henderson, B. Gaudi, Samson A. Johnson, N. Koshimoto, M. Meyer, G. Mulders, S. Mullally, R. Murray-Clay, D. Nataf, E. Nielsen, H. Ngo, I. Pascucci, M. Penny, P. Plavchan, R. Poleski, C. Ranc, S. Raymond, L. Rogers, J. Sahlmann, K. Sahu, J. Schlieder, Y. Shvartzvald, A. Sozzetti, R. Street, T. Sumi, D. Suzuki, N. Zimmerman
The Kepler, K2 and TESS transit surveys are revolutionizing our understanding of planets orbiting close to their host stars and our understanding of exoplanet systems in general, but there remains a gap in our understanding of wide-orbit planets. This gap in our understanding must be filled if we are to understand planet formation and how it affects exoplanet habitability. We summarize current and planned exoplanet detection programs using a variety of methods: microlensing (including WFIRST), radial velocities, Gaia astrometry, and direct imaging. Finally, we discuss the prospects for joint analyses using results from multiple methods and obstacles that could hinder such analyses. We endorse the findings and recommendations published in the 2018 National Academy report on Exoplanet Science Strategy. This white paper extends and complements the material presented therein.
{"title":"Wide-Orbit Exoplanet Demographics","authors":"D. Bennett, R. Akeson, Y. Alibert, Jay Anderson, E. Bachelet, J. Beaulieu, A. Bellini, A. Bhattacharya, A. Boss, V. Bozza, S. Bryson, D. Buzasi, S. Novati, J. Christiansen, S. Domagal‐Goldman, M. Endl, B. Fulton, C. Henderson, B. Gaudi, Samson A. Johnson, N. Koshimoto, M. Meyer, G. Mulders, S. Mullally, R. Murray-Clay, D. Nataf, E. Nielsen, H. Ngo, I. Pascucci, M. Penny, P. Plavchan, R. Poleski, C. Ranc, S. Raymond, L. Rogers, J. Sahlmann, K. Sahu, J. Schlieder, Y. Shvartzvald, A. Sozzetti, R. Street, T. Sumi, D. Suzuki, N. Zimmerman","doi":"10.7892/BORIS.143128","DOIUrl":"https://doi.org/10.7892/BORIS.143128","url":null,"abstract":"The Kepler, K2 and TESS transit surveys are revolutionizing our understanding of planets orbiting close to their host stars and our understanding of exoplanet systems in general, but there remains a gap in our understanding of wide-orbit planets. This gap in our understanding must be filled if we are to understand planet formation and how it affects exoplanet habitability. We summarize current and planned exoplanet detection programs using a variety of methods: microlensing (including WFIRST), radial velocities, Gaia astrometry, and direct imaging. Finally, we discuss the prospects for joint analyses using results from multiple methods and obstacles that could hinder such analyses. \u0000We endorse the findings and recommendations published in the 2018 National Academy report on Exoplanet Science Strategy. This white paper extends and complements the material presented therein.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78633335","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}
E. Cordelli, P. Schlatter, P. Lauber, T. Schildknecht
The precise knowledge of the positions of space debris objects and in particular of defunct satellites is fundamental for satellite operations. Several studies showed that it is possible to improve the accuracy of the orbit determination results by fusing different types of observables, i.e. classical astrometric positions and range measurements. Particularly promising in the space debris field are the ranges provided by a satellite laser ranging system. The factors that limit the applicability of the satellite laser ranging (SLR) techniques are the altitude of the target, the accuracy of the predicted ephemeris of the target, the energy of the laser pulse, and the laser field of view. In this paper we will show a way to overcome the mentioned challenges by using a night-tracking camera for the real time correction of the pointing of the SLR system (active tracking), and for the simultaneous acquisition of measurements used to improve the orbits and to study the attitude of the target. After presenting the basic functionalities, the performance of the night-tracking camera, and the procedure to acquire the measurements, we will also show the potential of this tool to allow improving orbits in real-time. This study is carried out for defunct or recently decommissioned satellites. Only real angular/laser measurements provided by the sensors of the Swiss Optical Ground Station and Geodynamics Observatory Zimmerwald (SwissOGS) owned by the Astronomical Institute of the University of Bern (AIUB) are used.
{"title":"Use of a Night-Tracking Camera for Characterization and Orbit improvement of Defunct Spacecraft","authors":"E. Cordelli, P. Schlatter, P. Lauber, T. Schildknecht","doi":"10.7892/BORIS.139356","DOIUrl":"https://doi.org/10.7892/BORIS.139356","url":null,"abstract":"The precise knowledge of the positions of space debris objects and in particular of defunct satellites is fundamental for satellite operations. Several studies showed that it is possible to improve the accuracy of the orbit determination results by fusing different types of observables, i.e. classical astrometric positions and range measurements. Particularly promising in the space debris field are the ranges provided by a satellite laser ranging system. The factors that limit the applicability of the satellite laser ranging (SLR) techniques are the altitude of the target, the accuracy of the predicted ephemeris of the target, the energy of the laser pulse, and the laser field of view. In this paper we will show a way to overcome the mentioned challenges by using a night-tracking camera for the real time correction of the pointing of the SLR system (active tracking), and for the simultaneous acquisition of measurements used to improve the orbits and to study the attitude of the target. After presenting the basic functionalities, the performance of the night-tracking camera, and the procedure to acquire the measurements, we will also show the potential of this tool to allow improving orbits in real-time. This study is carried out for defunct or recently decommissioned satellites. Only real angular/laser measurements provided by the sensors of the Swiss Optical Ground Station and Geodynamics Observatory Zimmerwald (SwissOGS) owned by the Astronomical Institute of the University of Bern (AIUB) are used.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74280217","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 : 2019-02-20DOI: 10.1051/0004-6361/201935321
H. C'anovas, C. Cantero, L. Cieza, A. Bombrun, U. Lammers, B. Mer'in, A. Mora, 'Alvaro Ribas, D. Ru'iz-Rodr'iguez
The Ophiuchus cloud complex is one of the best laboratories to study the earlier stages of the stellar and protoplanetary disc evolution. The wealth of accurate astrometric measurements contained in the Gaia Data Release 2 can be used to update the census of Ophiuchus member candidates. We seek to find potential new members of Ophiuchus and identify those surrounded by a circumstellar disc. We constructed a control sample composed of 188 bona fide Ophiuchus members. Using this sample as a reference we applied three different density-based machine learning clustering algorithms (DBSCAN, OPTICS, and HDBSCAN) to a sample drawn from the Gaia catalogue centred on the Ophiuchus cloud. The clustering analysis was applied in the five astrometric dimensions defined by the three-dimensional Cartesian space and the proper motions in right ascension and declination. The three clustering algorithms systematically identify a similar set of candidate members in a main cluster with astrometric properties consistent with those of the control sample. The increased flexibility of the OPTICS and HDBSCAN algorithms enable these methods to identify a secondary cluster. We constructed a common sample containing 391 member candidates including 166 new objects, which have not yet been discussed in the literature. By combining the Gaia data with 2MASS and WISE photometry, we built the spectral energy distributions from 0.5 to $22microm$ for a subset of 48 objects and found a total of 41 discs, including 11 Class II and 1 Class III new discs. Density-based clustering algorithms are a promising tool to identify candidate members of star forming regions in large astrometric databases. If confirmed, the candidate members discussed in this work would represent an increment of roughly 40% of the current census of Ophiuchus.
{"title":"A census of $rho$ Oph candidate members from Gaia DR2","authors":"H. C'anovas, C. Cantero, L. Cieza, A. Bombrun, U. Lammers, B. Mer'in, A. Mora, 'Alvaro Ribas, D. Ru'iz-Rodr'iguez","doi":"10.1051/0004-6361/201935321","DOIUrl":"https://doi.org/10.1051/0004-6361/201935321","url":null,"abstract":"The Ophiuchus cloud complex is one of the best laboratories to study the earlier stages of the stellar and protoplanetary disc evolution. The wealth of accurate astrometric measurements contained in the Gaia Data Release 2 can be used to update the census of Ophiuchus member candidates. We seek to find potential new members of Ophiuchus and identify those surrounded by a circumstellar disc. We constructed a control sample composed of 188 bona fide Ophiuchus members. Using this sample as a reference we applied three different density-based machine learning clustering algorithms (DBSCAN, OPTICS, and HDBSCAN) to a sample drawn from the Gaia catalogue centred on the Ophiuchus cloud. The clustering analysis was applied in the five astrometric dimensions defined by the three-dimensional Cartesian space and the proper motions in right ascension and declination. The three clustering algorithms systematically identify a similar set of candidate members in a main cluster with astrometric properties consistent with those of the control sample. The increased flexibility of the OPTICS and HDBSCAN algorithms enable these methods to identify a secondary cluster. We constructed a common sample containing 391 member candidates including 166 new objects, which have not yet been discussed in the literature. By combining the Gaia data with 2MASS and WISE photometry, we built the spectral energy distributions from 0.5 to $22microm$ for a subset of 48 objects and found a total of 41 discs, including 11 Class II and 1 Class III new discs. Density-based clustering algorithms are a promising tool to identify candidate members of star forming regions in large astrometric databases. If confirmed, the candidate members discussed in this work would represent an increment of roughly 40% of the current census of Ophiuchus.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"79 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72969169","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}
T. Campante, S. Barros, O. Demangeon, H. J. D. N'obrega, J. Kuszlewicz, F. Pereira, W. Chaplin, D. Huber
Space-based asteroseismology has been playing an important role in the characterization of exoplanet-host stars and their planetary systems. The future looks even brighter, with space missions such as NASA's TESS and ESA's PLATO ready to take on this legacy. In this contribution, we provide an outlook on the synergy between asteroseismology and exoplanet science, namely, on the prospect of conducting a populational study of giant planets around oscillating evolved stars with the TESS mission.
{"title":"Synergy between asteroseismology and exoplanet science: an outlook","authors":"T. Campante, S. Barros, O. Demangeon, H. J. D. N'obrega, J. Kuszlewicz, F. Pereira, W. Chaplin, D. Huber","doi":"10.5281/zenodo.2463210","DOIUrl":"https://doi.org/10.5281/zenodo.2463210","url":null,"abstract":"Space-based asteroseismology has been playing an important role in the characterization of exoplanet-host stars and their planetary systems. The future looks even brighter, with space missions such as NASA's TESS and ESA's PLATO ready to take on this legacy. In this contribution, we provide an outlook on the synergy between asteroseismology and exoplanet science, namely, on the prospect of conducting a populational study of giant planets around oscillating evolved stars with the TESS mission.","PeriodicalId":8428,"journal":{"name":"arXiv: Earth and Planetary Astrophysics","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74827473","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}
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