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Title: DISCOVERY OF TWO RARE RIGIDLY ROTATING MAGNETOSPHERE STARS IN THE APOGEE SURVEY

The Apache Point Observatory Galactic Evolution Experiment (APOGEE)—one of the Sloan Digital Sky Survey III programs—is using near-infrared (NIR) spectra of ∼100,000 red giant branch star candidates to study the structure of the Milky Way. In the course of the survey, APOGEE also acquires spectra of hot field stars to serve as telluric calibrators for the primary science targets. We report the serendipitous discovery of two rare, fast-rotating B-stars of the σ Ori E type among those blue field stars observed during the first year of APOGEE operations. Both of the discovered stars display the spectroscopic signatures of rigidly rotating magnetospheres (RRM) common to this class of highly magnetized (B ∼ 10 kGauss) stars, increasing the number of known RRM stars by ∼10%. One (HD 345439) is a main-sequence B-star with unusually strong He absorption (similar to σ Ori E), while the other (HD 23478) fits a ''He-normal'' B3IV classification. We combine the APOGEE discovery spectra with other optical and NIR spectra of these two stars, and of σ Ori E itself, to show how NIR spectroscopy can be a uniquely powerful tool for discovering more of these rare objects, which may show little/no RRM signatures in their optical spectra.more » We discuss the potential for further discovery of σ Ori E type stars, as well as the implications of our discoveries for the population of these objects and insights into their origin and evolution.« less
Authors:
;  [1] ; ; ; ; ; ; ; ;  [2] ;  [3] ;  [4] ; ;  [5] ;  [6] ; ;  [7] ;  [8] ;  [9] ;  [10] more »; « less
  1. Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611 (United States)
  2. Department of Astronomy, University of Virginia, 530 McCormick Rd, Charlottesville, VA 22904 (United States)
  3. Department of Astronomy, University of Oklahoma, 440 W. Brooks St., Norman, OK 73019 (United States)
  4. University of Texas, McDonald Observatory, 3640 Dark Sky Drive, Fort Davis, TX (United States)
  5. Apache Point Observatory, 2001 Apache Point Rd, Sunspot, NM 88349 (United States)
  6. Department of Astronomy, University of Washington, Box 351580, U.W., Seattle, WA 98195-1580 (United States)
  7. Department of Astronomy, New Mexico State University, 1780 E University Ave, Las Cruces, NM 88003 (United States)
  8. Department of Physics and Astronomy, Texas Christian University, Box 298840, Fort Worth, TX 76129 (United States)
  9. Instituto de Astrofísica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain)
  10. Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)
Publication Date:
OSTI Identifier:
22365942
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 784; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; ABSORPTION SPECTRA; GALACTIC EVOLUTION; HELIUM; MAGNETIC FIELDS; MAIN SEQUENCE STARS; MILKY WAY; NEAR INFRARED RADIATION; ORIGIN; POTENTIALS; STELLAR MAGNETOSPHERES