epsilon Aurigae eclipse observations

More than one thousand professional astronomers will be meeting in Boston to compare notes on a wide variety of astronomy and astrophysics at the spring meeting of the American Astronomical Society, jointly held with AAVSO.  On the varied agenda will be 4 posters and at least 2 talks about the status of epsilon Aurigae eclipse studies and Citizen Sky support of these activities.  I plan to summarize what the campaign effort has meant for professionals and amateurs, as well as report on the discovery of high temperature helium absorption in infrared spectra during mid-eclipse.  Naomi Pequette has applied powerful disk modelling software to epsilon Aur data and concludes that a fair amount of accretion must be occuring.  Brian Kloppenborg will report on progress toward improving the orbital solution for epsilon Aurigae, by combining astrometric, spectroscopic and interferometric data.  Brian will also be reporting on how Citizen Sky teamwork has fared, and ARead more

You might want to make the effort to get outside and estimate the visual brightness of epsilon Aurigae now, as it appears to be close to a minimum, about 3.75.  This is possibly the faintest it will be this year and for years to come, if the end of eclipse begins in mid/late March as forecast.  This assumes that the recent ~67 day in eclipse light variation behavior persists.  In that event, we should see return to a local maximum, perhaps V ~ 3.65 in mid/late Feb, followed by a decline - until third contact.

Observers are reporting visual magnitude approaching 3.4, which is half-way between the out of eclipse average, close to 3.0, and the anticipated magnitude during totality, 3.8.  Hopkins and Santangelo have begun to converge on JD 2,455,065 (+/- a few days) as the likely time of first contact (start of eclipse).  Today being JD 2,455,127 (23 Oct), that was 62 days ago.   At this rate, we'll bottom out in totality by JD 2,455,189 or slightly sooner - close to winter solstice.  Jeff Hopkins predicts 2,455,183 for visual, and earlier in photometrically bluer wavelengths.Read more

Robin Leadbeater just provided spectroscopic evidence that the eclipse is starting - and on the 40th anniversary of Apollo 11 moonlanding.
Leadbeater has been following the neutral potassium absorption line at 7699A in the far red, and reports a doubling of the equivalent width (area inside the curve).   The new component has appeared about 1/3A longward of the longterm line, corresponding to a redshift of about 20 to 25 km/sec, which is consistent with radial velocity of ingress (see Lambert and Sawyer, 1986: http://adsabs.harvard.edu/abs/1986PASP...98..389L -- figure 2, attached.
Photometric confirmation is eagerly anticipated.  Congrats Robin!
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