Astronomical and Astrophysical Transactions, Vol. 32, No. 2

This issue of Astronomical and Astrophysical Transactions comprises the papers presented at the tenth annual conference on Modern Stellar Astronomy, held in Special Astrophysical Observatory of the Russian Academy of Sciences in October 2019. The “Modern Stellar Astronomy” conferences provide a forum for Russian scientists and scientists from the former Soviet Union concerned with stellar astronomy and related topics. The program consisted of invited talks, contributed oral talks, and poster papers. There were about 110 registered participants at the meeting. The program of the 2019 conference included 84 oral and 26 poster presentations. The key topics for the conference were Binary stars, Variable stars, Stellar clusters, Star formation, Exoplanets, Structure, kinematics and dynamics of the Milky Way Galaxy, Other galaxies. This volume comprises eleven of the papers that were presented at the conference.

The Development of Physical Cosmology

This chapter introduces physical cosmology as the attempt to make sense of the large-scale nature of the material world by the methods of the natural sciences. It explains that physical cosmology operates under the special restrictions of astronomy, which is considered successful in sister fields, such as stellar astronomy and particle physics. It cites the substantial progress of cosmology as an enterprise in physical science, although the advances certainly have moved around considerable gaps in one's understanding. The chapter details how cosmology inherits from basic physics the more ancient and honorable tradition of attempts to understand where the world came from, where it is going, and why. It reviews believable evidence that the universe is expanding, the space between the galaxies opening up, and that this expansion traces back to a hot dense phase, the big bang.

Alexander Nikolaevich Deutsch on the occasion of his 120th anniversary

The year 2019 is the year of the 120th anniversary of Alexander Nikolaevich Deutsch (1899-1986), the Pulkovo astronomer, doctor of physical and mathematical Sciences, Professor, who for many years was the head of the Department of photographic astrometry and stellar astronomy of the Main Astronomical Observatory, Russian Academy of Sciences (GAO RAS), the supervisor and teacher of several generations of Pulkovo astronomers and employees of other observatories. This article presents the scientific and social activities of A.N. Deutsch. Archived data is provided that evidence his participation, along with other Pulkovo employees, in the salvation of the property and scientific Fund of the Pulkovo Observatory during the great Patriotic war, as well as in the work to restore the Observatory. The article is based on the presentation given to and approved by the conference "Astrometry: yesterday, today, tomorrow" (Sternberg Astronomical Institute, Moscow State University, October 14-16, 2019).

Science of the Vatican Observatory since 2000

Five research areas have been the focus of the scientific work of the Specola Vaticana (Vatican Observatory) over the past twenty years: planetary sciences, stellar astronomy, extragalactic astronomy, cosmology, and the development of the Vatican Advanced Technology Telescope (vatt). The choice of research program is left to the individual astronomers, all of whom work closely with lay collaborators around the world. Notable, especially in connection with the vatt, is the close coordination of the Specola with the Steward Observatory of the University of Arizona. One unique strength of the Specola is its independence from short-term funding requirements. As a result of its stable funding, Specola astronomers can engage in long-term research programs such as surveys of meteorite properties, exoplanets, stellar clusters, and galaxy clusters, which may take ten or more years to come to fruition. In this way the Specola complements the large research programs of contemporary astronomy.

On the matter of proving Euclidean fifth postulate and the origin of non-Euclidean geometries

The Euclidean geometry was developed as a mathematical system due to generalizing thousands years of measurements on the plane and spherical surfaces. The development of celestial mechanics and stellar astronomy confirmed its validity as mathematical principles of natural philosophy, in particular for studying the Solar System bodies’ and Galaxy stars motions. In the non-Euclidean geometries by Lobachevsky and Riemann, the third axiom of modern geometry manuals is substituted. We show that the third axiom of these manuals is a corollary of the Fifth Euclidean postulate. The idea of spherical, Riemannian space of the Universe and local curvatures of space, depending on body mass, was inculcated into celestial mechanics, astronomy and geodesy along with the theory of relativity. The mathematical apparatus of the relativity theory was created from immeasurable quantities

George Ellery Hale’s Internationalism

Throughout his career, George Ellery Hale thought globally. “Make no small plans” he was often heard to say (Seares 1939). His early sojourns to Europe, encountering the talent and resources in England and the Continent, contributed to his outlook. He knew that their patronage was critical to reach his personal goals. Here I outline the steps Hale took to establish the new “astrophysics” as a discipline, by creating the Astrophysical Journal, establishing a common language and then, through the first decades of the 20th Century, building an international collaboration to coordinate solar and later all astronomical research. The latter effort, which began in 1904, had expanded by 1910 to encompass stellar astronomy, when the Solar Union deliberated over spectroscopic classification systems, a standard wavelength system and stellar magnitude systems. This work continued through the fifth Union meeting in Bonn in 1913, which turned out to be the last because of the First World War. During the war, Hale became Chair of the National Research Council of the U.S. National Academy of Sciences, applying scientific talent to winning the war. He was also the Academy’s Foreign Secretary, so Hale became deeply involved in re-establishing international scientific relations after the war. In conjunction with Arthur Schuster and Emile Picard, he helped found the International Research Council in 1919, which formed the framework within which the worlds of science reorganized themselves. From this, the International Astronomical Union was born. It was not an easy birth in a world still filled with tension and anger over the war; formative conferences in London and Brussels reflected the extremes. Nevertheless, its first General Assembly was held in Rome in 1922. It would be years before it became truly international, “in the complete sense of the word” (Elis Strömgren), but many of the proposals made during the years of the Solar Union concerning disciplinary standardization were ratified. I will concentrate on this latter story, remembering Hale for his devotion to true internationalism.

Binary orbits from combined astrometric and spectroscopic data

An efficient Bayesian technique for estimation problems in fundamental stellar astronomy is tested on simulated data for a binary observed both astrometrically and spectroscopically. Posterior distributions are computed for the components’ masses and for the binary’s parallax. One thousand independent repetitions of the simulation demonstrate that the 1- and 2-σ credibility intervals for these fundamental quantities have close to the correct coverage fractions. In addition, the simulations allow the investigation of the statistical properties of a Bayesian goodness-of-fit criterion and of the corresponding p-value. The criterion has closely similar properties to the traditional χ2 test for minimum-χ2 solutions.

Conference “Modern Stellar Astronomy 2017”

Here we give a brief overview on the eighth annual conference on Modern Stellar Astronomy held in the Ural FederalUniversity (Ekaterinbourg, Russia) in June 2017, to commemorate the 100th birthday of Prof. K. Barkhatova (1917-1990).