Asteroid Discovered at Baldone Observatory Named After Singer-Songwriter Rozenštrauhs

The International Astronomical Union (IAU) approved this summer a permanent number and name for an asteroid discovered in 2011 at the Baldone Astrophysics Observatory of the University of Latvia (LU). The object is now called (856173) Rozenštrauhs, in honour of the Latvian singer-songwriter Eduards Rozenštrauhs.

The discovery

The new object in the Solar System's main asteroid belt was spotted shortly after midnight on 3 September 2011. It was found by Ilgmārs Eglītis, lead researcher at the LU Institute of Astronomy and head of the Baldone observatory, using the Baldone Schmidt telescope. Kazimieras Černis, a researcher at Vilnius University, provided the precise coordinate measurements.

At the moment of discovery the asteroid sat very low in the sky in the constellation Pisces. Its brightness was magnitude 20.5, so it could be seen only with the very powerful Baldone telescope. It first received the provisional designation 2011 SF81. The name, proposed by the discoverer, was published in the IAU's WGSBNBulletin.

Orbit and size

The asteroid is about one kilometre across. It orbits at an average of 1.81 astronomical units, roughly 271 million kilometres, from the Sun. Its orbit is elongated and elliptical and lies between Mars and Jupiter. As a result, the asteroid occasionally comes closer to Earth's orbit than 1 astronomical unit, about 122 million kilometres. One orbit takes 3.65 years.

During six oppositions, when the asteroid approaches Earth, 103 measurements have been collected. They allow its position to be determined over a 100-year span with an accuracy of up to 0.73 arcseconds.

Why this name

Eglītis says the name recalls childhood memories of family birthdays, where guests sang Rozenštrauhs's songs to his father's guitar. He mentions "Vecpiebalgas ūdensrozes", "Vecās dzirnas", "Jāņu nakts" and "Jaunība", as well as "Zilais lakatiņš", which became an anthem of the Latvian riflemen. Eglītis agrees with an encyclopedia assessment that Rozenštrauhs is a phenomenon in Latvian post-war music history: an officially unrecognised yet popularly loved musician whose songs spread by word of mouth.