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Title: CONSTRAINTS ON LONG-PERIOD PLANETS FROM AN L'- AND M-BAND SURVEY OF NEARBY SUN-LIKE STARS: OBSERVATIONS

Journal Article · · Astrophysical Journal
; ; ; ;  [1];  [2]
  1. Steward Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States)
  2. Department of Physics, Swiss Federal Institute of Technology (ETH-Zurich), ETH Honggerberg, CH-8093 Zurich (Switzerland)

We present the observational results of an L'- and M-band adaptive optics imaging survey of 54 nearby, Sun-like stars for extrasolar planets, carried out using the Clio camera on the MMT. We have concentrated more strongly than all other planet-imaging surveys to date on very nearby F, G, and K stars, prioritizing stellar proximity higher than youth. Ours is also the first survey to include extensive observations in the M band, which supplement the primary L' observations. Models predict much better planet/star flux ratios at the L' and M bands than at more commonly used shorter wavelengths (i.e., the H band). We have carried out extensive blind simulations with fake planets inserted into the raw data to verify our sensitivity, and to establish a definitive relationship between source significance in {sigma} and survey completeness. We find 97% confident-detection completeness for 10{sigma} sources, but only 46% for 7{sigma} sources-raising concerns about the standard procedure of assuming high completeness at 5{sigma}, and demonstrating that blind sensitivity tests to establish the significance-completeness relation are an important analysis step for all planet-imaging surveys. We discovered a previously unknown {approx}0.15 M{sub sun} stellar companion to the F9 star GJ 3876, at a projected separation of about 80 AU. Twelve additional candidate faint companions are detected around other stars. Of these, 11 are confirmed to be background stars and one is a previously known brown dwarf. We obtained sensitivity to planetary-mass objects around almost all of our target stars, with sensitivity to objects below 3 M{sub Jup} in the best cases. Constraints on planet populations based on this null result are presented in our Modeling Results paper.

OSTI ID:
21448802
Journal Information:
Astrophysical Journal, Vol. 714, Issue 2; Other Information: DOI: 10.1088/0004-637X/714/2/1551; ISSN 0004-637X
Country of Publication:
United States
Language:
English