The Subaru Telescope at the Mauna Kea Observatory on Hawaii.

Strategic Explorations of Exoplanets and Disks with Subaru (SEEDS) is a multi-year survey that used the Subaru Telescope on Mauna Kea, Hawaii in an effort to directly image extrasolar planets and protoplanetary/debris disks around hundreds of nearby stars.[1] SEEDS is a Japanese-led international project. It consists of some 120 researchers from a number of institutions in Japan, the U.S. and the EU.[2] The survey's headquarters is at the National Astronomical Observatory of Japan (NAOJ) and led by Principal Investigator Motohide Tamura. The goals of the survey are to address the following key issues in the study of extrasolar planets and disks: the detection and census of exoplanets in the regions around solar-mass and massive stars; the evolution of protoplanetary disks and debris disks; and the link between exoplanets and circumstellar disks.[1]

Observations and Results

Kappa Andromedae b, the Super-Jupiter exoplanet of 12.8 Jupiter masses discovered as part of the SEEDS survey
The confirmed brown dwarf GJ 758 B and the candidate GJ 758 C, which was later found to be a background star

The direct imaging survey was carried out with a suite of high-contrast instrumentation at the large Subaru 8.2 m telescope, including a second-generation adaptive optics (AO) system with 188 actuators (AO188) and a dedicated coronagraph instrument called HiCIAO. [3][4] Observations began in late October 2009 and were completed in early January 2015, having observed roughly 500 nearby stars (including duplicates). The survey was conducted in the H-band (1.65 micron) and once a planet/companion candidate was detected, it was also observed at other near-infrared wavelengths.[2]

SEEDS has reported four candidate planets to date. The first one is GJ 758 b, with a mass around 10–30 Jupiter masses and orbiting around a Sun-like star. The projected distance from the central star to the companion is 29 AU at a distance of around 52 light years.[5][6] The second discovery was of a very faint planet orbiting a Sun-like star named GJ 504.[7] The projected distance from the central star is 44 AU at a distance of 59 light years. The central star itself is bright, visible to the naked-eye (V ~ 5 mag), but the planet is very dim, 17–20 mag at infrared wavelengths. The planet mass is estimated to be only 3–4.5 Jupiter masses, estimated from its luminosity and age. It is one of the lightest-mass planets ever imaged.[2]

The survey also discovered a likely superjovian-mass planet named Kappa Andromedae b, orbiting a young B-type star 2.8 times the mass of Sun.[8] HD 100546 b was confirmed as a planet with a disk system around a very young star as part of the SEEDS survey. SEEDS has also reported the detection of three brown dwarfs in the Pleiades cluster as part of the Open Cluster category survey and several stellar or substellar companions around planetary systems, from the radial velocity detection. SEEDS has detected interesting fine-structures in disks around dozens of young stars. These disks exhibit gaps, spiral arms, rings, and other structures at similar radial distances where the outer planets are imaged. These structures can be considered to be "signposts" of planets. The results obtained on disks support the need for a new planet formation model.[2][9]

Additional planet and disk discoveries include:

See also

References

  1. ^ a b Tamura, Motohide (August 2009). "Subaru Strategic Exploration of Exoplanets and Disks with HiCIAO/AO188 (SEEDS)". AIP Conference Proceedings. 1158 (1): 11–16. Bibcode:2009AIPC.1158...11T. doi:10.1063/1.3215811.
  2. ^ a b c d TAMURA, Motohide (2016-02-10). "SEEDS — Strategic explorations of exoplanets and disks with the Subaru Telescope —". Proceedings of the Japan Academy. Series B, Physical and Biological Sciences. 92 (2): 45–55. Bibcode:2016PJAB...92...45T. doi:10.2183/pjab.92.45. ISSN 0386-2208. PMC 4906811. PMID 26860453.
  3. ^ Tamura, Motohide; et al. (July 2006). McLean, Ian S; Iye, Masanori (eds.). "Concept and science of HiCIAO: high contrast instrument for the Subaru next generation adaptive optics" (PDF). Proceedings of the SPIE. Ground-based and Airborne Instrumentation for Astronomy. 6269: 62690V. Bibcode:2006SPIE.6269E..0VT. CiteSeerX 10.1.1.662.5117. doi:10.1117/12.670742. S2CID 67780784.
  4. ^ Hodapp, Klaus; et al. (August 2008). McLean, Ian S; Casali, Mark M (eds.). "HiCIAO: the Subaru Telescope's new high-contrast coronographic imager for adaptive optics" (PDF). Proceedings of the SPIE. Ground-based and Airborne Instrumentation for Astronomy II. 7014: 42H. Bibcode:2008SPIE.7014E..19H. doi:10.1117/12.788088. S2CID 3870419.
  5. ^ Thalmann, Christian; et al. (December 2009). "Discovery of the Coldest Imaged Companion of a Sun-Like Star". Astrophysical Journal Letters. 707 (2): L123–L127. arXiv:0911.1127. Bibcode:2009ApJ...707L.123T. doi:10.1088/0004-637X/707/2/L123. S2CID 116823073.
  6. ^ Janson, Markus; et al. (January 2011). "Near-infrared Multi-band Photometry of the Substellar Companion GJ 758 B". The Astrophysical Journal. 728 (2): 85. arXiv:1011.5505. Bibcode:2011ApJ...728...85J. doi:10.1088/0004-637X/728/2/85. S2CID 119296265.
  7. ^ Kuzuhara, Masayuki; et al. (August 2013). "Direct Imaging of a Cold Jovian Exoplanet in Orbit around the Sun-like Star GJ 504". Astrophysical Journal. 774 (1): 11. arXiv:1307.2886. Bibcode:2013ApJ...774...11K. doi:10.1088/0004-637X/774/1/11. S2CID 53343537.
  8. ^ Carson, Joseph; et al. (January 2013). "Direct Imaging Discovery of a 'Super-Jupiter' Around the late B-Type Star Kappa And". Astrophysical Journal Letters. 763 (2): 32. arXiv:1211.3744. Bibcode:2013ApJ...763L..32C. doi:10.1088/2041-8205/763/2/L32. S2CID 119253577.
  9. ^ a b Thalmann, Christian; et al. (December 2011). "Images of the Extended Outer Regions of the Debris Ring around HR 4796 A". Astrophysical Journal Letters. 743 (1): 6. arXiv:1110.2488. Bibcode:2011ApJ...743L...6T. doi:10.1088/2041-8205/743/1/L6. S2CID 14131310.
  10. ^ Hashimoto, Jun; et al. (March 2011). "Direct Imaging of Fine Structures in Giant Planet-forming Regions of the Protoplanetary Disk Around AB Aurigae". Astrophysical Journal Letters. 729 (2): 17. arXiv:1102.4408. Bibcode:2011ApJ...729L..17H. doi:10.1088/2041-8205/729/2/L17. S2CID 118665967.
  11. ^ Thalmann, Christian; et al. (August 2010). "Imaging of a Transitional Disk Gap in Reflected Light: Indications of Planet Formation Around the Young Solar Analog LkCa 15". Astrophysical Journal. 718 (2): L87–L91. arXiv:1005.5162. Bibcode:2010ApJ...718L..87T. doi:10.1088/2041-8205/718/2/L87. S2CID 26500380.
  12. ^ Narita, Norio; et al. (June 2010). "Search for Outer Massive Bodies around Transiting Planetary Systems: Candidates of Faint Stellar Companions around HAT-P-7". Publications of the Astronomical Society of Japan. 62 (3): 779–786. arXiv:1004.2458. Bibcode:2010PASJ...62..779N. doi:10.1093/pasj/62.3.779.
  13. ^ Thalmann, Christian; et al. (February 2013). "Imaging Discovery of the Debris Disk Around HIP 79977". Astrophysical Journal Letters. 763 (2): 29. arXiv:1301.0625. Bibcode:2013ApJ...763L..29T. doi:10.1088/2041-8205/763/2/L29. S2CID 119259358.
  14. ^ Mayama, Satoshi; et al. (December 2012). "Subaru Imaging of Asymmetric Features in a Transitional Disk in Upper Scorpius". Astrophysical Journal Letters. 760 (2): 26. arXiv:1211.3284. Bibcode:2012ApJ...760L..26M. doi:10.1088/2041-8205/760/2/L26. S2CID 52998952.
  15. ^ Hashimoto, Jun; et al. (October 2012). "Polarimetric Imaging of Large Cavity Structures in the Pre-transitional Protoplanetary Disk around PDS 70: Observations of the Disk". Astrophysical Journal Letters. 758 (1): 19. arXiv:1208.2075. Bibcode:2012ApJ...758L..19H. doi:10.1088/2041-8205/758/1/L19. S2CID 13691976.
  16. ^ Muto, Takayuki; et al. (April 2012). "Discovery of Small-scale Spiral Structures in the Disk of SAO 206462 (HD 135344B): Implications for the Physical State of the Disk from Spiral Density Wave Theory". Astrophysical Journal Letters. 748 (2): 22. arXiv:1202.6139. Bibcode:2012ApJ...748L..22M. doi:10.1088/2041-8205/748/2/L22. S2CID 118374349.
  17. ^ Narita, Norio; et al. (December 2012). "A Common Proper Motion Stellar Companion to HAT-P-7". Publications of the Astronomical Society of Japan. 64 (2): 7. arXiv:1209.4422. Bibcode:2012PASJ...64L...7N. doi:10.1088/2041-8205/748/2/L22. S2CID 118374349.
  18. ^ Grady, C.A.; et al. (January 2013). "Spiral Arms in the Asymmetrically Illuminated Disk of MWC 758 and Constraints on Giant Planets". Astrophysical Journal. 762 (1): 48. arXiv:1212.1466. Bibcode:2013ApJ...762...48G. doi:10.1088/0004-637X/762/1/48. S2CID 54930830.
  19. ^ Tanii, Ryoko; et al. (December 2012). "High-Resolution Near-Infrared Polarimetry of a Circumstellar Disk around UX Tau A". Publications of the Astronomical Society of Japan. 64 (6): 124. arXiv:1206.1215. Bibcode:2012PASJ...64..124T. doi:10.1093/pasj/64.6.124.
  20. ^ Kusakabe, Nobuhiko; et al. (July 2012). "High-Contrast NIR Polarization Imaging of MWC480". Astrophysical Journal. 753 (2): 153. arXiv:1205.3159. Bibcode:2012ApJ...753..153K. doi:10.1088/0004-637X/753/2/153. S2CID 119114993.
  21. ^ Thalmann, Christian; et al. (Feb 2014). "The architecture of the LkCa 15 transitional disk revealed by high-contrast imaging". Astronomy & Astrophysics. 566: 23. arXiv:1402.1766. Bibcode:2014A&A...566A..51T. doi:10.1051/0004-6361/201322915. S2CID 34485844.
  22. ^ Tsukagoshi, Takashi; et al. (Feb 2014). "High-Resolution Submillimeter and Near-Infrared Studies of the Transition Disk around Sz 91". Astrophysical Journal. 783 (2): 90. arXiv:1402.1538. Bibcode:2014ApJ...783...90K. doi:10.1088/0004-637X/783/2/90. S2CID 49393475.
  23. ^ de Leon, Jerome; Takami, Michihiro; Karr, Jennifer L.; Hashimoto, Jun; Kudo, Tomoyuki; Sitko, Michael; Mayama, Satoshi; Kusakabe, Nobuyuki; Akiyama, Eiji (2015-06-04). "Near-IR High-Resolution Imaging Polarimetry of the SU Aur Disk: Clues for Tidal Tails?". The Astrophysical Journal. 806 (1): L10. arXiv:1505.03610. Bibcode:2015ApJ...806L..10D. doi:10.1088/2041-8205/806/1/L10. ISSN 2041-8213. S2CID 22225752.
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