RV Variability in the IC 348 field

Primary Contacts

David Nidever
University of Michigan
dnidever -at- umich.edu
Kevin Covey
Western Washington University
kevin.covey -at- wwu.edu

Other contacts

Rohit Deshpande (rsd15 -at- psu.edu)
Drew Chojnowski (drewski -at- nmsu.edu)


The RV Variability in IC 348 program used a jointly designed set of APOGEE plates to extend the completeness or temporal coverage of several types of ancillary targets located in a field containing the young cluster IC 348.

Finding Targets

An object whose APOGEE_TARGET2 value includes one or more of the bitmasks in the following table was targeted for spectroscopy as part of this ancillary target program. See SDSS bitmasks to learn how to use these values to identify objects in this ancillary target program.

Program (bit name) Bit number Target Description
APOGEE_RV_MONITOR_IC348 18 RV variability target in IC 348 field


The RV Variability in IC 348 program used a jointly designed set of APOGEE plates to advance multiple science goals: 1) a search for substellar companions to bright field stars of all spectral types; 2) a search for stellar and substellar companions around low-mass M star targets, and 3) enhancing the completeness of the IN-SYNC sample in the crowded-limited regions of IC 348.

Target Selection Details

Previous APOGEE observations of IC 348 conducted for the IN-SYNC ancillary program resulted in a spectroscopic sample that was highly complete in the cluster’s outer regions, but with lower completeness in the cluster’s central regions, where fiber collisions prevented the observation of targets within 71″ of one another.

To help improve the completeness of the IN-SYNC sample, eight distinct plate designs were produced for the RV Variability in IC 348 program. The first 40 targets for each of these designs were selected from a list of candidate IC 348 members with H < 13.5, sorted according to the number of APOGEE visits previously obtained, or expected to be obtained via other plates designed for this program. An additional 190 targets where then added to each of these 8 plate designs, to provide an extensive set of multi-epoch observations for investigations of RV and/or spectroscopic variability. These 190 targets consisted of:

  • 8 M dwarf field stars with H <=12.05, selected from the Lépine & Shara (2005) or Lépine & Gaidos (2011) proper motion catalogs;
  • 92 Bright field stars with 7 < H < 9.7 and reduced proper motions indicating that they are nearby dwarf stars;
  • 1 star (HD 23478/BD+31 649) newly identified as a Herbig Be object in previous APOGEE observations of this field;
  • 89 additional IC 348 targets, selected from the subset of the IN-SYNC sample with the highest number of existing epochs, to provide the best sensitivity for identifying new pre-main sequence spectroscopic binaries.


Chojnowski et al. 2015, AJ, 149, 7
Cottaar et al. 2014, ApJ, 497, 125
Deshpande et al. 2013, AJ, 146, 156
Lépine & Shara 2005, AJ, 129, 1483
Lépine & Gaidos 2011, AJ, 142, 138