AAVSO Alert Notice 397:
Request for optical photometry of the bright X-ray binary V884 Sco (4U 1700-377)
June 30, 2009
Dr. Jerome Orosz (SDSU) has requested the assistance of southern bright star observers in observing the high-mass X-ray binary star V884 Sco (== 4U 1700-377). 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 (V ~ 6.5) system beginning now (2009 June 30) and continuing through early August 2009.
V884 Sco is a binary system composed of a massive, main sequence O-type star in orbit with either a black hole or a neutron star. Dr. Orosz provides the following justification for the project:
“…[A] note about the importance of 4U 1700-377. 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.”
V884 Sco is a low-amplitude (amplitude < 0.04 mag) variable star which shows ellipsoidal variations rather than binary eclipses. The period of the star is approximately 3.45 days. Photometry is requested to obtain a current ephemeris; examination of data from the 1970s makes clear the period of the system has changed. ASAS-3 data do exist for this star and are being used, but the star is near the bright limit for the ASAS system. Observers capable of performing precision bright star photometry are encouraged to participate, particularly those in the southern hemisphere.
V884 Sco is located at the following (J2000) coordinates:
RA: 17 03 56.80 , Dec: -37 50 39.0
For this project, we recommend the use of HD 153767 (SAO 208340; RA: 17 03 00.34 , Dec: -37 43 10.8 , V=7.43) as the comparison star. This will require either a CCD camera with a field of view larger than 15 arcminutes, or a photoelectric photometer. If you are using a CCD camera, use short exposures to avoid saturating the chip, or stop down your telescope. If you choose to stop down your system, new flat fields should be created. For photoelectric observers, we recommend using HD 154310 (SAO 208406; RA: 17 06 20.19 , Dec: -37 13 39.3 , V=5.98) as the check star. This is a known double, but the B component is four magnitudes fainter than A, and should not interfere with the photometry. These comparison and check stars have been added to the PEPObs online processing program. Johnson B and V filters are the preferred filters if they are available, but data taken in any filter will be useful and all observers are encouraged to participate.
Charts for the field may be plotted with AAVSO’s Variable Star Plotter:
http://www.aavso.org/observing/charts/vsp/index.html?pickname=V884%20Sco
Please submit data to the AAVSO with the name “V884 SCO”.
This AAVSO Alert Notice was prepared by M. Templeton.
SUBMIT OBSERVATIONS TO THE AAVSO
Information on submitting observations to the AAVSO may be found at:
http://www.aavso.org/observing/submit/
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There was never literally nothing. That would violate the first law of thermodynamics and overturn all of physics as we understand it. Something NEVER comes from literally nothing. It is theists who insist upon a creation ex nihilo, from literally nothing. Didn’t God simply say, “let there be Light” and make it so? Most people are very well aware of the first law of thermodynamics (mass-energy can be neither created nor destroyed, only transformed) and mass-energy equivalence (E=mc^2), but I think few grasp the implications. It is this very concept that makes what theists propose, a creation ex nihilo, ridiculous. If we take matter-energy to be eternal, uncaused – as our best science seems to suggest (see the first law again), then existence is simply axiomatic. The universe just is, and the Big Bang becomes more or less a transitional event. The universe as we know it began with the Big Bang, but the matter-energy was always there, it must have been – to say otherwise turns all of physics as we understand it on its head. We know that matter-energy is conserved – always, in every instance we have ever observed or theorized about. It is but a simple and very reasonable extrapolation to then say that matter-energy has always been, and it is empirically evident. There is no need to postulate a creator or a creation ex nihlo. Looking at things from the perspective of a First Cause argument, which theists are quite fond of, for something to exercise influence on the universe this causal agent must have already existed. Something nonexistent can’t serve as a causal agent; thus causality must assume existence. Theists arguing for a creation of the universe ex nihlo, however have their logic backward – that existence assumes causation. In the end, the theist is reduced to demanding to know why there is something rather than nothing, but this begs the question, because it presumes that nothing or non-existence ought to be the natural state of things. This is like presuming the sky is supposed to be green and then citing the fact that it is blue as evidence for a Creator. A scientist does not ask “why is there something rather than nothing”, but rather “why SHOULDN’T there be something rather than nothing”. There isn’t anything about the universe that suggests it shouldn’t be here and be exactly as we observe it be. As for exactly how the universe as we know it began, theories abound. My personal favorite is Lee Smolin’s theory of fecund universes – in which a collapsing black hole generates another universe on the other side (what happened right after the BB and what happens in a black hole are very similar phenomena), and thus by a sort of cosmological natural selection we end up with universes favoring the formation of black holes. Then of course there is brane theory, multi-verse theory, quantum-tunneling and host of others. I think your problem here is really the problem of many people, and that is a misperception that things have to “come from” somewhere or something. The ham sandwich I ate for lunch today didn’t pop into being. Somebody made it, someone made the components in it, the pig grew from matter it took in, that matter at some point came from an exploding star…. From what I see with laws like the 1st law of thermodynamics is that existence is essentially axiomatic.