Radar and Lightcurve Shape Model of Near-Earth Asteroid (1627) Ivar

Jenna L. Crowell, Ellen S. Howell, Christopher Magri, Michael C. Nolan, Yanga R. Fernández, James E. Richardson, Brian D. Warner, Sean E. Marshall, Alessondra Springmann

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


We present our shape model of Amor class near-Earth asteroid (1627) Ivar. During Ivar's apparition in 2013, in which it had a minimum distance of 0.32 AU, we obtained both CCD photometry and radar observations. The radar data consist of echo power spectra and delay-Doppler imaging with 300 m resolution and were obtained using the Arecibo Observatory's 2380 MHz radar. Lightcurve data were gathered using the 0.35 m telescope at the Palmer Divide Station. Using these data, we constructed a detailed shape model of Ivar that reveals more surface detail than earlier models. Ivar was found to have a rotational period of 4.7951689 ± 0.0000026 hours with a pole located within 6° of ecliptic longitude and latitude 336° and 37° respectively. Ivar is an elongated asteroid with maximum extensions along the three body-fixed coordinates being 15.15 × 6.25 × 5.66 km ± 10%. The results of surface slope analysis suggest that Ivar is covered with a loose regolith. Ivar appears to reside in, or near, an optimum state with respect to its shape, spin, and bulk density, such that dynamic topography, surface slopes, and erosion rates on the body are near minimum levels and is therefore dynamically stable.

Original languageEnglish (US)
Pages (from-to)254-267
Number of pages14
StatePublished - Jul 15 2017

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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