No CrossRef data available.
Article contents
Meteoroid Streams
Published online by Cambridge University Press: 19 July 2016
Abstract
Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.
Meteoroid streams, producing meteor showers if some part of the stream has a node near 1 AU, have complex structures which are only just beginning to be understood. The old simplistic idea of a narrow loop being formed about the orbit of a parent comet with one, or possibly two, terrestrial intersection(s) is now being replaced by the recognition that their dynamical evolution may render convoluted and distorted ribbon shapes with eight or more distinct showers being generated. As such the streams are excellent tracers of the sorts of orbital evolution which may be undergone by larger objects (asteroids and comets) in the inner solar system; indeed it is now known that objects presently observed as Apollo-type asteroids may also be the progenitors of streams.
Searches for showers associated with newly-discovered possible parent objects may be carried out either via the calculation of theoretical meteor radiants (which have hitherto been derived using an untenable method), or through searches of catalogues of individual meteor orbits. In order to accomplish the latter, about 68,000 radar, photographic and TV meteor orbits from various programmes in the U.S.A., the former Soviet Union, Canada and Australia are available from the IAU Meteor Data Center, and more than 350,000 orbits of very faint meteors have been determined over the past three years using a new facility in New Zealand.
The discovery amongst IRAS data of dust trails lagging behind comets has opened up a new way in which meteoroid streams may be investigated, although the relationship between these trails and the streams observed as meteor showers at the Earth is by no means clear at this stage. Similarly radar, radio and spacecraft impact observations of meteoroids near cometary nuclei have added to our knowledge.
In spite of the improvement in our understanding of meteoroid streams over the past few years it is clear that there is much still to be done. The words of W.F. Denning in 1923 are still pertinent: “Few astronomers occupy themselves with the observation and investigation of meteors, and yet it is an attractive field of work offering inviting prospects of new discoveries”.
- Type
- Populations of Small Bodies
- Information
- Symposium - International Astronomical Union , Volume 160: Asteroids, Comets, Meteors 1993 , 1994 , pp. 111 - 126
- Copyright
- Copyright © Kluwer 1994
References
Asher, D.J., Clube, S.V.M. and Steel, D.I.: 1993, “Asteroids in the Taurid Complex.”
Mon. Not. Roy. Astron. Soc., 264, 93–105.CrossRefGoogle Scholar
Babadzhanov, P.B.: 1990, “Formation of twin meteor showers.”. In Asteroids, Comets, Meteors III (Lagerkvist, C.-I., Rickman, H., Lindblad, B. A. and Lindgren, M., Eds.), 497–503, University of Uppsala, Sweden.Google Scholar
Babadzhanov, P.B., Hajduk, A., Obrubov, Yu.V. and Pushkarev, A.N.: 1991a, “Evolution of meteoroid streams of comet Halley.”
Astron. Vestn., 25, 208–216;
Sol. Sys. Res., 25, 153–160.Google Scholar
Babadzhanov, P.B., Isamutdinov, Sh.O. and Chebotarev, R.P.: 1992, “Some structural features of the Geminid meteor shower.”
Astron. Vestn., 26, 93–97.Google Scholar
Babadzhanov, P.B. and Obrubov, Yu.V.: 1992a, “P/Machholz 1986 VIII and Quadrantid meteoroid stream. Orbital evolution and relationship.” In Asteroids, Comets, Meteors 1991 (Harris, A.W. and Bowell, E., Eds.), 27–32, Lunar and Planetary Inst., Houston.Google Scholar
Babadzhanov, P.B. and Obrubov, Yu.V.: 1992b, “Evolution of short-period meteor streams.”
Cel. Mech. Dynam. Astron., 54, 111–127.CrossRefGoogle Scholar
Babadzhanov, P.B., Obrubov, Yu.V. and Makhmudov, N.: 1990, “Encke meteor showers.”
Astron. Vestn., 24, 18–28;
Sol. Sys. Res., 24, 12–19.Google Scholar
Babadzhanov, P.B., Wu, Z., Williams, I.P. and Hughes, D.W.: 1991b, “The Leonids, Comet Biela and Biela's associated meteoroid stream.”
Mon. Not. Roy. Astron. Soc., 253, 69–74.Google Scholar
Baggaley, W.J.: 1977, “The possibility of the detection of meteor streams in interplanetary space.”
The Observatory, 97, 123–129.Google Scholar
Baggaley, W.J. and Taylor, A.D.: 1992, “Radar meteor orbital structure of southern hemisphere cometary dust streams.” In Asteroids, Comets, Meteors 1991 (Harris, A.W. and Bowell, E., Eds.), 33–36, Lunar and Planetary Inst., Houston.Google Scholar
Baggaley, W.J., Taylor, A.D. and Steel, D.I.: 1992, “New determinations of radar orbits for meteors from short-period comets.” In Periodic Comets (Fernández, J.A. and Rickman, H., Eds.), 115–124, Universidad de la República, Montevideo, Uruguay.Google Scholar
Bailey, M.E., Clube, S.V.M. and Napier, W.M.: 1990, The Origin of Comets, Pergamon, Oxford.Google Scholar
Beech, M.: 1988, “Meteor astronomy: a mature science?”
Earth, Moon & Planets, 43, 187–194.Google Scholar
Bel'kovich, O.I.: 1986, “On the spatial structure of the Geminid meteor shower.”
Astron. Vestn., 20, 142–151;
Sol. Sys. Res., 20, 93–101.Google Scholar
Bradley, J.P., Brownlee, D.E. and Fraundorf, P.: 1984, “Discovery of nuclear tracks in interplanetary dust.”
Science, 226, 1432–1434.Google Scholar
Burns, J.A., Lamy, Ph.L. and Soter, S.: 1979, “Radiation forces on small particles in the solar system.”
Icarus, 40, 1–48.Google Scholar
Campbell, D.B., Harmon, J.K. and Shapiro, I.I.: 1989, “Radar observations of comet Halley.”
Astrophys. J., 338, 1094–1105.Google Scholar
Cook, A.F.: 1973, “A Working List of Meteor Streams.”. In Evolutionary and Physical Properties of Meteoroids, NASA SP–319 (Hemenway, C.L., Millman, P.M. and Cook, A.F., Eds.), 183–191, NASA, Washington D.C.Google Scholar
Cook, A.F., Flannery, M.R., Levy, H., McCrosky, R.E., Sekanina, Z., Shao, C.-Y., Southworth, R.B. and Williams, J.T.: 1972, Meteor Research Program, NASA CR–2109, Smithsonian Astrophysical Observatory, Cambridge, Mass.
Google Scholar
Crovisier, J. and Schloerb, F.P.: 1991, “The study of comets at radio wavelengths.” In Comets in the Post-Halley Era (Newburn, R.L. Jr., Neugebauer, M. and Rahe, J., Eds.), 149–173, Kluwer, Dordrecht.Google Scholar
Dodd, R.T., Wolf, S.F. and Lipschutz, M.E.: 1993, “An H Chondrite Stream: Identification and Confirmation.”
J. Geophys. Res., 98, 15105–15118.CrossRefGoogle Scholar
Drummond, J.D.: 1981a, “A test of comet and meteor shower associations.”
Icarus, 45, 545–553.Google Scholar
Drummond, J.D.: 1981b, “Earth-orbit-approaching comets and their theoretical radiants.”
Icarus, 47, 500–517.Google Scholar
Drummond, J.D.: 1982a, “Theoretical twin meteor showers.”
Icarus, 49, 135–142.CrossRefGoogle Scholar
Drummond, J.D.: 1982b, “Theoretical meteor radiants of Apollo, Amor and Aten asteroids.”
Icarus, 49, 143–153.Google Scholar
Ellyett, C.D. and Kennewell, J.A.: 1977, “Radar meteor rates and atmospheric density changes.”
Nature, 287, 521–522.Google Scholar
Emel'yanenko, V.V.: 1991, “Dynamics of the Lyrid meteor swarm.”
Astron. Vestn., 24, 308–313;
Sol. Sys. Res., 24, 199–202.Google Scholar
Emel'yanenko, V.V.: 1992, “Dynamics of periodic comets and meteor streams.”
Cel. Mech. Dynam. Astron., 54, 91–110.Google Scholar
Fox, K. and Williams, I.P.: 1985, “A possible origin for some ancient December fireballs.”
Mon. Not. Roy. Astron. Soc., 217, 407–411.Google Scholar
Fox, K., Williams, I.P. and Hughes, D.W.: 1982, “The evolution of the orbit of the Geminid meteor stream.”
Mon. Not. Roy. Astron. Soc., 200, 313–324.Google Scholar
Fox, K., Williams, I.P. and Hughes, D.W.: 1983, “The rate profile of the Geminid meteor shower.”
Mon. Not. Roy. Astron. Soc., 205, 1155–1169.Google Scholar
Froeschlé, C. and Scholl, H.: 1986, “Gravitational splitting of Quadrantid-like meteor streams in resonance with Jupiter.”
Astron. Astrophys., 158, 259–265.Google Scholar
Fulle, M.: 1990, “Meteoroids from short period comets.”
Astron. Astrophys., 230, 220–226.Google Scholar
Grün, E., et al.: 1993, “The discovery of jovian dust streams and interstellar grains by the Ulysses spacecraft.”
Nature, 362, 428–430.Google Scholar
Grün, E., Zook, H.A., Fechtig, H. and Giese, R.H.: 1985, “Collisional balance of the meteoritic complex.”
Icarus, 62, 244–272.Google Scholar
Gustafson, B.Å.S.: 1989, “Geminid meteoroids traced to cometary activity on Phaethon.”
Astron. Astrophys., 225, 533–540.Google Scholar
Gyssens, M., Knöfel, A., Rendtel, J. and Roggemans, P.: 1991, “The International Meteor Organization.” In IAU Colloq. 126: Origin and Evolution of Interplanetary Dust (Levasseur-Regourd, A.C. and Hasegawa, H., Eds.), 335–338, Kluwer, Dordrecht.Google Scholar
Hahn, G. and Bailey, M.E.: 1990, “Rapid dynamical evolution of giant comet Chiron.”
Nature, 348, 132–136.Google Scholar
Hajduk, A.: 1991, “Evolution of cometary debris: physical aspects.” In Comets in the Post-Halley Era, (Newburn, R.L. Jr., Neugebauer, M. and Rahe, J., Eds.), 592–606, Kluwer, Dordrecht.Google Scholar
Hajduková, M. and Hajduk, A.: 1991, “Lifetime of meteor streams associated with comet Halley.” In IAU Colloq. 126: Origin and Evolution of Interplanetary Dust (Levasseur-Regourd, A.C. and Hasegawa, H., Eds.), 323–326, Kluwer, Dordrecht.Google Scholar
Halliday, I., Blackwell, A.T. and Griffin, A.A.: 1990, “Evidence for the existence of groups of meteorite-producing asteroidal fragments.”
Meteoritics, 25, 93–99.Google Scholar
Harmon, J.K., Campbell, D.B., Hine, A.A., Shapiro, I.I. and Marsden, B.G.: 1989, “Radar observations of comet IRAS-Iraki-Alcock 1983d.”
Astrophys. J., 338, 1071–1093.Google Scholar
Hasegawa, I.: 1990, “Predictions of the Meteor Radiant Point Associated with a Comet.”
Publ. Astron. Soc. Japan, 42, 175–186.Google Scholar
Hasegawa, I.: 1992, “Historical variation in the meteor flux as found in Chinese and Japanese chronicles.”
Cel. Mech. Dynam. Astron., 54, 129–142.Google Scholar
Hasegawa, I., Ueyama, Y. and Ohtsuka, K.: 1992, “Predictions of the Meteor Radiant Point Associated with an Earth-Approaching Minor Planet.”
Publ. Astron. Soc. Japan, 44, 45–54.Google Scholar
Hughes, D.W. and McBride, N.: 1989, “The mass of meteoroid streams.”
Mon. Not. Roy. Astron. Soc., 240, 73–79.Google Scholar
Hughes, D.W., Williams, I.P. and Fox, K.: 1981, “The mass segregation and nodal regression of the Quadrantid meteor stream.”
Mon. Not. Roy. Astron. Soc., 195, 625–637.Google Scholar
Hunt, J., Williams, I.P. and Fox, K.: 1985, “Planetary perturbations on the Geminid meteor stream.”
Mon. Not. Roy. Astron. Soc., 217, 533–538.Google Scholar
Jones, J.: 1982, “The annual variation in the activity of the Geminid shower and the theory of the dispersal of meteoroid clusters.”
Mon. Not. Roy. Astron. Soc., 198, 23–32.Google Scholar
Jones, J.: 1985, “The structure of the Geminid meteor stream – I. The effect of planetary perturbations.”
Mon. Not. Roy. Astron. Soc., 217, 523–532.Google Scholar
Jones, J.: 1986, “The effect of gravitational perturbations on the evolution of the Taurid meteor stream complex.”
Mon. Not. Roy. Astron. Soc., 221, 257–267.Google Scholar
Jones, J. and Hawkes, R.L.: 1986, “The structure of the Geminid meteor stream – II. The combined action of the cometary ejection process and gravitational perturbations.”
Mon. Not. Roy. Astron. Soc., 223, 479–486.Google Scholar
Jones, J. and Jones, W.: 1992, “Evolution of the Quadrantid meteor stream.” In Asteroids, Comets, Meteors 1991 (Harris, A.W. and Bowell, E., Eds.), 269–272, Lunar and Planetary Inst., Houston.Google Scholar
Jones, J., McIntosh, B.A. and Hawkes, R.L.: 1989, “The age of the Orionid meteoroid stream.”
Mon. Not. Roy. Astron. Soc., 238, 179–191.Google Scholar
Jones, J. and Morton, J.D.: 1982, “High resolution radar studies of the Geminid meteor shower.”
Mon. Not. Roy. Astron. Soc., 200, 281–291.Google Scholar
Kidger, M.R.: 1993, “Some Comments on the Identification of Medieval Meteor Showers Recorded by the Arabs.”
Q. Jl. Roy. Astron. Soc., 34, 331–334.Google Scholar
Kresák, Ľ: 1993, “Meteor storms”. In Meteoroids and their parent bodies (Štohl, J. and Williams, I.P., Eds.), 147–156, Astron. Inst., Slovak Acad. Sci., Bratislava.Google Scholar
Kresáková, M.: 1987, “Associations between ancient comets and meteor showers.”
Bull. Astron. Inst. Czechoslov., 38, 75–80.Google Scholar
Kulikova, N.V.: 1989, “The Draconid meteor stream (numerical simulation).”
Astron. Vestn., 23, 289–295;
Sol. Sys. Res., 23, 175–179.Google Scholar
Lebedinets, V.N., Kulikova, N.V. and Pivnenko, E.A.: 1990, “Effect of reactive deceleration of comets on the structure of meteor swarms.”
Astron. Vestn., 24, 3–17;
Sol. Sys. Res., 24, 1–11.Google Scholar
Lindblad, B.A.: 1990, “The orbit of the Eta Aquarid meteor stream.” In Asteroids, Comets, Meteors III (Lagerkvist, C.-I., Rickman, H., Lindblad, B. A. and Lindgren, M., Eds.), 551–554, University of Uppsala, Sweden.Google Scholar
Lindblad, B.A.: 1991, “The IAU Meteor Data Center in Lund.” In IAU Colloq. 126: Origin and Evolution of Interplanetary Dust (Levasseur-Regourd, A.C. and Hasegawa, H., Eds.), 311–314, Kluwer, Dordrecht.Google Scholar
Lindblad, B.A. and Porubčan, V.: 1992, “Activity of the Lyrid meteor stream.” In Asteroids, Comets, Meteors 1991 (Harris, A.W. and Bowell, E., Eds.), 367–370, Lunar and Planetary Inst., Houston.Google Scholar
McIntosh, B.A.: 1990, “Comet P/Machholz and the Quadrantid meteor stream.”
Icarus, 86, 299–304.Google Scholar
McIntosh, B.A.: 1991, “Debris from comets: the evolution of meteor streams.” In Comets in the Post-Halley Era (Newburn, R.L. Jr., Neugebauer, M. and Rahe, J., Eds.), 557–591, Kluwer, Dordrecht.Google Scholar
McIntosh, B.A. and Jones, J.: 1988, “The Halley comet meteor stream: Numerical modelling of its dynamical evolution.”
Mon. Not. Roy. Astron. Soc., 235, 673–693.Google Scholar
Morton, J.D. and Jones, J.: 1982, “A method of imaging radio meteor radiant distributions.”
Mon. Not. Roy. Astron. Soc., 198, 737–746.Google Scholar
Oberst, J. and Nakamura, Y.: 1991, “A search for clustering among the meteoroid impacts detected by the Apollo lunar seismic network.”
Icarus, 91, 315–325.Google Scholar
Olsson-Steel, D.: 1986, “The origin of the sporadic meteoroid component.”
Mon. Not. Roy. Astron. Soc., 219, 47–73.Google Scholar
Olsson-Steel, D.: 1987, “Theoretical meteor radiants of Earth-approaching asteroids and comets.”
Aust. J. Astron., 2, 21–35; see also 2, 93–101 (1988).Google Scholar
Olsson-Steel, D.: 1988, “Identification of meteoroid streams associated with Apollo asteroids in the Adelaide radar orbit surveys.”
Icarus, 75, 64–96.Google Scholar
Padevět, V.: 1973, “Motion of a fragment in disturbed air behind a meteor body.” In Evolutionary and Physical Properties of Meteoroids, NASA SP–319 (Hemenway, C.L., Millman, P.M. and Cook, A.F., Eds.), 169–174, NASA, Washington D.C.Google Scholar
Poole, L.M.G. and Roux, D.G.: 1989, “Meteor radiant mapping with an all-sky radar.”
Mon. Not. Roy. Astron. Soc., 236, 645–652.Google Scholar
Porubčan, V. and Cevolani, C.: 1990, “On the activity and structure of the Quadrantid meteor stream.”
Nuovo Cimento, 13, 653–662.Google Scholar
Porubčan, V. and Štohl, J.: 1992, “Burst of the 1969 Leonids and 1982 Lyrids.” In Asteroids, Comets, Meteors 1991 (Harris, A.W. and Bowell, E., Eds.), 469–472, Lunar and Planetary Inst., Houston.Google Scholar
Porubčan, V., Štohl, J. and Vaňa, R.: 1992, “On associations of Apollo asteroids with meteor streams.” In Asteroids, Comets, Meteors 1991 (Harris, A.W. and Bowell, E., Eds.), 473–476, Lunar and Planetary Inst., Houston.Google Scholar
Rabinowitz, D.L.: 1993, “The size distribution of Earth-approaching asteroids.”
Astrophys. J., 407, 412–427.Google Scholar
Rada, W.S. and Stephenson, F.R.: 1992, “A Catalogue of Meteor Showers in Medieval Arab Chronicles.”
Q. Jl. Roy. Astron. Soc., 33, 5–16.Google Scholar
Ridley, H.B.: 1962, “The Phoenicid meteor shower of 1956 December 5.”
J. Brit. Astron. Assoc., 72, 266–272.Google Scholar
Ryabova, G.O.: 1989, “The effect of secular perturbations and the Poynting-Robertson effect on the structure of the Geminid meteor stream.”
Astron. Vestn., 23, 254–264;
Sol. Sys. Res., 23, 158–165.Google Scholar
Sandford, S.A.: 1991, “Constraints on the parent bodies of collected interplanetary dust particles.” In IAU Colloq. 126: Origin and Evolution of Interplanetary Dust (Levasseur-Regourd, A.C. and Hasegawa, H., Eds.), 397–404, Kluwer, Dordrecht.Google Scholar
Šimek, M. and Lindblad, B.A.: 1990, “The activity curve of the Perseid meteor stream as determined from short duration meteor radar echoes.” In Asteroids, Comets, Meteors III, (Lagerkvist, C.-I., Rickman, H., Lindblad, B. A. and Lindgren, M., Eds.), 567–570, University of Uppsala, Sweden.Google Scholar
Šimek, M. and McIntosh, B.A.: 1991, “Cross section of the Quadrantid meteor stream.”
Bull. Astron. Inst. Czechoslov., 42, 124–132.Google Scholar
Singer, S.F. and Stanley, J.E.: 1980, “Submicron particles in meteor streams.” In IAU Symp. 90, Solid Particles In the Solar System (Halliday, I. and McIntosh, B.A., Eds.) 329–332, Reidel, Dordrecht.Google Scholar
Steel, D.: 1991, “The orbital distribution and origin of meteoroids.” In IAU Colloq. 126: Origin and Evolution of Interplanetary Dust (Levasseur-Regourd, A.C. and Hasegawa, H., Eds.), 291–298, Kluwer, Dordrecht.Google Scholar
Steel, D.I., Asher, D.J. and Clube, S.V.M.: 1991, “The structure and evolution of the Taurid Complex.”
Mon. Not. Roy. Astron. Soc., 251, 632–648.Google Scholar
Štohl, J.: 1987, “Meteor contribution by short-period comets.”
Astron. Astrophys., 187, 933–934.Google Scholar
Štohl, J. and Porubčan, V.: 1990, “Structure of the Taurid meteor complex.” In Asteroids, Comets, Meteors III, (Lagerkvist, C.-I., Rickman, H., Lindblad, B. A. and Lindgren, M., Eds.), 571–574, University of Uppsala, Sweden.Google Scholar
Štohl, J. and Porubčan, V.: 1992, “Dynamical aspects of the Taurid meteor complex.” In IAU Symp. 152: Chaos, resonance and collective dynamical phenomena in the solar system (Ferraz-Mello, S., Ed.), 315–324, Kluwer, Dordrecht.Google Scholar
Sykes, M.V. and Walker, R.G.: 1992, “Cometary Dust Trails. I. Survey.”
Icarus, 95, 180–210.Google Scholar
Terentjeva, A.K.: 1990, “Fireball streams.” In Asteroids, Comets, Meteors III, (Lagerkvist, C.-I., Rickman, H., Lindblad, B. A. and Lindgren, M., Eds.), 579–584, University of Uppsala, Sweden.Google Scholar
Whipple, F.L.: 1951, “A Comet Model. II. Physical Relations for Comets and Meteors.”
Astrophys. J., 113, 464–474.Google Scholar
Whipple, F.L.: 1967, “On maintaining the meteoritic complex.” In The Zodiacal Light and the Interplanetary Medium, NASA SP-150 (Weinberg, J.L., Ed.), 409–426, NASA, Washington D.C.
Google Scholar
Whipple, F.L. and Hamid, S.E.: 1952, “On the origin of the Taurid meteor streams.”
Helwan Obs. Bull., 41, 224–252.Google Scholar
Williams, I.P.: 1990, “The formation of meteor streams.” In Asteroids, Comets, Meteors III (Lagerkvist, C.-I., Rickman, H., Lindblad, B. A. and Lindgren, M., Eds.), 585–594, University of Uppsala, Sweden.Google Scholar
Williams, I.P.: 1992, “The dynamics of meteoroid streams.” In IAU Symp. 152: Chaos, resonance and collective dynamical phenomena in the solar system (Ferraz-Mello, S., Ed.), 299–313, Kluwer, Dordrecht.Google Scholar
Williams, I.P., Johnson, C. and Fox, K.: 1986, “Meteor Storms.” In Asteroids, Comets, Meteors II (Lagerkvist, C.-I., Lindblad, B. A., Lundstedt, H. and Rickman, H., Eds.), 559–563, University of Uppsala, Sweden.Google Scholar
Williams, I.P. and Wu, Z.: 1993, “The Quadrantid meteoroid stream and Comet 1491 I.”
Mon. Not. Roy. Astron. Soc., 264, 659–664.Google Scholar
Wu, Z. and Williams, I.P.: 1992a, “Formation of the Leonid Meteor Stream and Storm.” In Asteroids, Comets, Meteors 1991, (Harris, A.W. and Bowell, E., Eds.), 661–665, Lunar and Planetary Inst., Houston.Google Scholar
Wu, Z. and Williams, I.P.: 1992b, “On the Quadrantid meteoroid stream complex.”
Mon. Not. Roy. Astron. Soc., 259, 617–628.Google Scholar
Wu, Z. and Williams, I.P.: 1993, “The Perseid meteor shower at the present time.”
Mon. Not. Roy. Astron. Soc., 264, 980–990.Google Scholar
Yeomans, D.K.: 1981, “Comet Tempel–Tuttle and the Leonid meteors.”
Icarus, 47, 492–499.Google Scholar
Yeomans, D.K. and Kiang, T.: 1981, “The long-term motion of comet Halley.”
Mon. Not. Roy. Astron. Soc., 197, 633–646.Google Scholar
Zausaev, A.F. and Pushkarev, A.N.: 1989, “The orbital evolution of the Quadrantid meteor stream during 4000 years (AD 1950 to 2050 BC).”
Byull. Inst. Astrofiz., 80, 18–24.Google Scholar
You have
Access