Bergelmir (// bair-YEL-meer) or Saturn XXXVIII (38) (provisional designation S/2004 S 15) is a natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, Jan Kleyna, and Brian G. Marsden on May 4, 2005, from observations taken between December 12, 2004, and March 9, 2005.
Bergelmir is about 6 kilometres in diameter, and orbits Saturn at an average distance of 19,372 Mm in 1006.659 days, at an inclination of 157° to the ecliptic (134° to Saturn's equator), in a retrograde direction and with an eccentricity of 0.152. Its rotation period is 8.13±0.09 hours.
It was named in April 2007 after Bergelmir, a giant from Norse mythology and the grandson of Ymir, the primordial giant. Bergelmir and his wife alone among their kind were the only survivors of the enormous deluge of blood from Ymir's wounds when he was killed by Odin and his brothers at the dawn of time. Bergelmir then became the progenitor of a new race of giants.
- Denk, T.; Mottola, S. (2019). Cassini Observations of Saturn's Irregular Moons (PDF). 50th Lunar and Planetary Science Conference. Lunar and Planetary Institute.
- Institute for Astronomy Saturn Satellite Data
- Jewitt's New Satellites of Saturn page
- IAUC 8523: New Satellites of Saturn[permanent dead link] May 4, 2005 (discovery)
- MPEC 2005-J13: Twelve New Satellites of Saturn May 3, 2005 (discovery and ephemeris)
- IAUC 8826: Satellites of Jupiter and Saturn[permanent dead link] April 5, 2007 (naming the moon)