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TOPIC: Period increase of 28 Tau ?

Period increase of 28 Tau ? 9 years 6 months ago #29

Based on two observation campaigns at 28 Tau, observer of the ARAS community had been able, with the Halpha radial velocity as indicator, to observe two periastron passages (see attachment):

1. JD 2455955.414 (January, 28th 2012)
2. JD 2456213.499 (October, 10th 2012)

The time of the first periastron does fit well with Nemravova┬┤s ephemeries (A&A, 516, A80, 2010) and the 218d period. The deviation amounts 1 day only. The time of the second periastron at JD 2456213.5 could mean, that the period has increased from 218d to 258d. Based on these new ephemeries, the next periastron passage should take place at June, 27th 2013.

Remarkable is that the disk pertubation through the companion, almost contemporaneous is measurable as changes of the Halpha V/R ratio. We may be tense, on which level the radial velocity will be stable during the coming weeks.
Comments are welcome.

Ernst Pollmann
Active Spectroscopy in Astronomy
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Period increase of 28 Tau ? 9 years 6 months ago #30

Please see here the graph that should have been attached to the above post:

Sorry for the inconvenience, we're still fine tuning the upload mechanism...
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