NOAO >   Observing Info >   Approved Programs >   2010B-0144

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Proposal Information for 2010B-0144


PI: John Stocke, U of Colorado, stocke@casa.colorado.edu
Address: CASA/APS, UCB 389 U of Colorado, Boulder, CO 80302, USA

CoI: Cynthia Froning, CASA, U of Colorado
CoI: Juthika Khargharia, CASA, U of Colorado
CoI: Bal Chandra Joshi, National Centre for Radio Astronomy, Pune, India
CoI: A. Gopakumar, Tata Institute for Fundamental Research, Mumbai, India

Title: A Unique Milli-Second Pulsar System

Abstract: We propose to obtain three epochs of GMOS-N spectroscopy of the likely companion to a unique new milli-second pulsar in a highly eccentric orbit. Pulsar timing provides an accurate mass for the companion star (1M_\odot) and its orbital period (95 days). Near-IR images detect a star at the pulsar position with colors consistent with a highly-reddened G star but its association with the pulsar is not proven. Spectra at the Ca Triplet are requested to confirm the spectral type, detect orbital motion (90 km s^-1 full change expected) and measure or set a limit on rotation speed for accurate periastron shift interpretation. If it can be shown that the G star is the only companion, then this system provides ``clean'' new tests of General Relativity. But without this proof, made possible by these proposed spectra, the close-in pulsar companion could be a white dwarf with the G star being a distant third body in the system. Three epochs of observation of three telescope hours each are required to test this hypothesis.


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