1181 Lilith (prov. designation: ) is a metallic asteroid from the middle region of the asteroid belt, approximately in diameter. It was discovered on 11 February 1927, by RussianâÂÂFrench astronomer Benjamin Jekhowsky at Algiers Observatory in Algeria, Northern Africa, and named after French composer Lili Boulanger.
Lilith is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements. It orbits the Sun in the middle asteroid belt at a distance of 2.1âÂÂ3.2 AU once every 4 years and 4 months (1,587 days). Its orbit has an eccentricity of 0.20 and an inclination of 6ð with respect to the ecliptic. First observed as at Simeiz Observatory in 1914, Liliths observation arc begins 7 years after its official discovery observation, with its first used observation made at Konkoly Observatory in 1934.
This minor planet was named by Jekhowsky for Marie Juliette Boulanger (1893âÂÂ1918), nicknamed Lili. She was the younger sister of Nadia Boulanger and daughter of Ernest Boulanger.
Lilith is an X-type asteroid in the BusâÂÂBinzel SMASS taxonomy. It has also been classified as a P-type asteroid by NASA's space-based Wide-field Infrared Survey Explorer (WISE).
In February 2014, a rotational lightcurve of Lilith was obtained by Italian astronomer Andrea Ferrero at the Bigmuskie Observatory in Mombercelli, Italy. The photometric observations rendered a period of hours with a brightness amplitude of 0.11 in magnitude ().
According to NASA's WISE telescope with its subsequent NEOWISE mission, Lilith measures () kilometers in diameter and its surface has an albedo of (), while the Collaborative Asteroid Lightcurve Link assumes an albedo of 0.10, and calculates a diameter of 24.2 kilometers with an absolute magnitude of 11.2. The WISE team also published an alternative mean diameter () and an albedo of ().