7 papers
The forgotten bright star: Theta Eridani as a millenary stellar transient observed by Hipparchus, Ptolemy and al-Sufi
Idel Waisberg, Boaz Katz
Theta Eridani is a V=2.9 star that was nonetheless reported as one of the thirteen brightest stars in the night sky by both Ptolemy in his Almagest (137 AD) and by al-Sufi in his T…
Confirming Nunki as the closest core collapse progenitor candidate to the Sun
Idel Waisberg, Boaz Katz
We have recently suggested that Nunki=Sigma Sagittarii is the closest core collapse progenitor candidate to the Sun based on a VLTI/GRAVITY observation that unveiled it as a $6.5+6…
Upgrading Alpha Crucis to a seven star system. Discovery of Bb and orbital misalignment
Idel Waisberg, Boaz Katz
Alpha Crucis is the closest very high multiplicity massive star to the Sun. At its heart is the binary (A) + (B) Cru, which combin…
von Zeipel-Kozai-Lidov oscillations in nearby bright stars. I. Lambda Ophiuchi
Idel Waisberg, Ygal Klein, Boaz Katz
The challenge of constraining both the inner and the outer orbits in multiple stars has resulted in a growing abyss between the rich theoretical and the sparse observational studie…
Which is the most eccentric binary known? Insights from the 2023/4 pericenter passages of Zeta Boötis and Eta Ophiuchi
Idel Waisberg, Ygal Klein, Boaz Katz
There is a clear dearth of very eccentric binaries among those for which individual eccentricities can be measured. In this paper we report on observations of the two nearby, brigh…
Kozai Lidov Cycles = Simple Pendulum
Roi D. Basha, Ygal Y. Klein, Boaz Katz
The quadrupole Kozai mechanism, which describes the hierarchical three-body problem in the leading order, is shown to be equivalent to a simple pendulum where the change in the ecc…