TY - JOUR
T1 - A Deep and Wide Twilight Survey for Asteroids Interior to Earth and Venus
AU - Sheppard, Scott S.
AU - Tholen, David J.
AU - Pokorný, Petr
AU - Micheli, Marco
AU - Dell'antonio, Ian
AU - Fu, Shenming
AU - Trujillo, Chadwick A.
AU - Beaton, Rachael
AU - Carlsten, Scott
AU - Drlica-Wagner, Alex
AU - Martínez-Vázquez, Clara
AU - Mau, Sidney
AU - Santana-Ros, Toni
AU - Santana-Silva, Luidhy
AU - Sifón, Cristóbal
AU - Simha, Sunil
AU - Thirouin, Audrey
AU - Trilling, David
AU - Vivas, A. Katherina
AU - Zenteno, Alfredo
N1 - Funding Information:
Observations were obtained at Cerro-Tololo Inter-American Observatory, National Optical Astronomy Observatory, which are operated by the Association of Universities for Research in Astronomy, under contract with the National Science Foundation. This project used data obtained with the Dark Energy Camera (DECam), which was constructed by the Dark Energy Survey (DES) collaborating institutions: Argonne National Lab, University of California Santa Cruz, University of Cambridge, Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas-Madrid, University of Chicago, University College London, DES-Brazil consortium, University of Edinburgh, ETH-Zurich, University of Illinois at Urbana-Champaign, Institut de Ciencies de l’Espai, Institut de Fisica d’Altes Energies, Lawrence Berkeley National Lab, Ludwig-Maximilians Universitat, University of Michigan, National Optical Astronomy Observatory, University of Nottingham, Ohio State University, University of Pennsylvania, University of Portsmouth, SLAC National Lab, Stanford University, University of Sussex, and Texas A&M University. Funding for DES, including DECam, has been provided by the U.S. Department of Energy, National Science Foundation, Ministry of Education and Science (Spain), Science and Technology Facilities Council (UK), Higher Education Funding Council (England), National Center for Supercomputing Applications, Kavli Institute for Cosmological Physics, Financiadora de Estudos e Projetos, Fundação Carlos Chagas Filho de Amparo a Pesquisa, Conselho Nacional de Desenvolvimento Científico e Tecnológico and the Ministério da Ciência e Tecnologia (Brazil), the German Research Foundation-sponsored cluster of excellence “Origin and Structure of the Universe” and the DES collaborating institutions. D.T. was supported by NASA grant 80NSSC21K0807. P.P. was supported by NASA ISFM EIMM award, the NASA Cooperative Agreement 80GSFC21M0002 and NASA solar system Workings award 80NSSC21K0153. T.S.R. acknowledges funding from the NEO-MAPP project (H2020-EU-2-1-6/870377). C.M. was partially supported by the international Gemini Observatory, a program of NSF's NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation, on behalf of the Gemini partnership of Argentina, Brazil, Canada, Chile, the Republic of Korea, and the United States of America. This work was (partially) funded by the Spanish MICIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe” by the “European Union” through grant RTI2018-095076-B-C21, and the Institute of Cosmos Sciences University of Barcelona (ICCUB, Unidad de Excelencia María de Maeztu’) through grant CEX2019-000918-M. This work makes use of observations from the Las Cumbres Observatory global telescope network. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.
Publisher Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.
PY - 2022/10/1
Y1 - 2022/10/1
N2 - We are conducting a survey using twilight time on the Dark Energy Camera with the Blanco 4 m telescope in Chile to look for objects interior to Earth's and Venus' orbits. To date we have discovered two rare Atira/Apohele asteroids, 2021 LJ4 and 2021 PH27, which have orbits completely interior to Earth's orbit. We also discovered one new Apollo-type Near Earth Object (NEO) that crosses Earth's orbit, 2022 AP7. Two of the discoveries have diameters 31 km. 2022 AP7 is likely the largest Potentially Hazardous Asteroid (PHA) discovered in about eight years. To date we have covered 624 square degrees of sky near to and interior to the orbit of Venus. The average images go to 21.3 mag in the r band, with the best images near 22nd mag. Our new discovery 2021 PH27 has the smallest semimajor axis known for an asteroid, 0.4617 au, and the largest general relativistic effects (53 arcsec/century) known for any body in the solar system. The survey has detected 1/415% of all known Atira NEOs. We put strong constraints on any stable population of Venus co-orbital resonance objects existing, as well as the Atira and Vatira asteroid classes. These interior asteroid populations are important to complete the census of asteroids near Earth, including some of the most likely Earth impactors that cannot easily be discovered in other surveys. Comparing the actual population of asteroids found interior to Earth and Venus with those predicted to exist by extrapolating from the known population exterior to Earth is important to better understand the origin, composition, and structure of the NEO population.
AB - We are conducting a survey using twilight time on the Dark Energy Camera with the Blanco 4 m telescope in Chile to look for objects interior to Earth's and Venus' orbits. To date we have discovered two rare Atira/Apohele asteroids, 2021 LJ4 and 2021 PH27, which have orbits completely interior to Earth's orbit. We also discovered one new Apollo-type Near Earth Object (NEO) that crosses Earth's orbit, 2022 AP7. Two of the discoveries have diameters 31 km. 2022 AP7 is likely the largest Potentially Hazardous Asteroid (PHA) discovered in about eight years. To date we have covered 624 square degrees of sky near to and interior to the orbit of Venus. The average images go to 21.3 mag in the r band, with the best images near 22nd mag. Our new discovery 2021 PH27 has the smallest semimajor axis known for an asteroid, 0.4617 au, and the largest general relativistic effects (53 arcsec/century) known for any body in the solar system. The survey has detected 1/415% of all known Atira NEOs. We put strong constraints on any stable population of Venus co-orbital resonance objects existing, as well as the Atira and Vatira asteroid classes. These interior asteroid populations are important to complete the census of asteroids near Earth, including some of the most likely Earth impactors that cannot easily be discovered in other surveys. Comparing the actual population of asteroids found interior to Earth and Venus with those predicted to exist by extrapolating from the known population exterior to Earth is important to better understand the origin, composition, and structure of the NEO population.
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U2 - 10.3847/1538-3881/ac8cff
DO - 10.3847/1538-3881/ac8cff
M3 - Article
AN - SCOPUS:85139832315
SN - 0004-6256
VL - 164
JO - Astronomical Journal
JF - Astronomical Journal
IS - 4
M1 - 168
ER -