Request for optical photometry of the bright X-ray binary V884 Sco (4U 1700-377)

Active Dates: June 30, 2009 – Aug. 10, 2009


Abstract:

Dr. Jerome Orosz has requested the assistance of southern bright star observers in observing the high-mass X-ray binary star V884 Sco. Orosz and collaborators are attempting to measure the mass of the compact object to clarify whether the object is a black hole or a neutron star. Optical photometry of the ellipsoidal variations of V884 Sco will be used in conjunction with optical spectroscopy to be performed at Las Campanas in mid-July and early August 2009 to measure the dynamical properties of the system. Orosz requests time-series B and V observations of this bright system beginning now (2009 June 30) and continuing through early August 2009.

Justification:

If it has a neutron star, it has by far the most massive neutron star known. Furthermore, the high mass would rule out all sorts of equations of state for neutron star matter. On the other hand, if the compact object is a black hole, it would be by far the least massive black hole known, and its mass would raise all sorts of interesting questions about the formation of black holes, and what kinds of stars produce black holes.

Requested Data Types:

Photometry, Spectroscopy



Targets
Name Magnitude Variability Type Photometry Notes Spectroscopy Notes
BMAM-V884 11.90 EA

Cadence: Not Specified

Precision: 100

Cadence: Not Specified

Resolution: 250

Desired SNR: 100


Spectroscopy Lines:

No spectroscopy lines provided

Photometry Filters:

No photometry filters provided

Comparison Stars:

No comparison stars provided


Co-Authorship

Observers are not eligible for co-authorship.

Additional Observer Input:

Not provided

Additional Submission Location:

Not provided


Forum URL

N/A


Notes:

Principal Investigator: Dr. Jerome Orosz (SDSU); Imported Campaign (Alert Notice #397)