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Dear all, our professional spectroscopic friends from Mexico (see my post of March 24) have succeeded to collect 6 spectra in 9 nights with their 1.2m telescope and fiber-coupled spectrograph. Over about one quarter of the orbital period the radial velocity stayed stubbornly at +56 km/s (the value t...

Thanks a lot to Rainer Ehlert and to Robin Leadbeater for additional data. They nicely confirm what we think to know about the star (spectral type, luminosity class, rough metallicity from the other spectra, and absolute magnitude from Gaia parallax). This is reassuring. Robin's RVs may be inconclus...

Dear all, Klaus-Peter Schroeder from University of Guanajuato (Mexico) has proposed a new model hypothesis which might explain this mysterious system: The very high velocity of the occulting body needed to produce the short duration of the eclipses could be due to a very high eccentricity of the orb...

Hallo Rainer, sorry for replying so late. I was distracted by urgent work for the Gaia satellite mission. Excellent spectrum, thanks! I will carefully look at it tomorrow. As for the practical treatment of the spectra, I am not the expert to ask. I guess you can find more and better advice from othe...

Ah, sorry,
I mixed up the signs! Of course the RV should now be negative, and it should be positive in early April, not vice versa.
Uli

Dear Rainer, (and dear community) yes, this spectrum helps me, like the one by Uwe Zurmuehl posted further up, and like a third one that Keith Shank (Texas, USA) mailed to me directly. All three convincingly and conclusively say that the strong H-alpha emission line that I hypothesized does not exis...

Zurmuehl TYC1799 1159 1.png Dear Forum members, just now I received a spectrum from German amateur Uwe Zurmuehl, taken last night under difficult conditions. It looks like a normal K spectrum, with Na D, G band, H-alpha, -beta, -gamma in absorption, and no emission apparent. Uwe Zurmuehl commented ...

Many thanks to Stu Todd, this is the correct star.
Uli B.

Dear forum members, back in January, the bright star TYC 1799 1159 1 (9th-magnitude in the red wavelength range; in the visual range it is about 10th magnitude) was serendipitously discovered by a German amateur to be an eclipsing binary. In the night to March 7, a second minimum was observed, so th...

Hallo, I registered to the forum just today, following a suggestion by Ernst Pollmann. I am a retired professional astronomer, formerly one of the leaders of the Gaia project, but I enter here as a member of the German variable-stars (amateur) association BAV. Not an observer, but more of an advisor...