(8567) 1996 HW1

Near-Earth asteroid November 2025 yes (8567) 1996 HW 1 #FFC2E0 (8567) 1996 HW1 image 3D.png Shape model of 1996 HW 1 Tom Gehrels 23 April 1996 Steward Observatory (8567) 1996 HW 1 NEOAmor 21 November 2025 (JD 2461000.5) 0 2.96437 AU 1.12697 AU 2.04567 AU 0.44909 8.44896° 177.0929° 177.282° 314.321° 2.92592 y (1068.69 d) 0.33686° / d 0.12152 AU 3.652 2.02 km226 3.78 0.19 × 1.64 0.16 × 1.49 0.22 km226Uncertainties are given as 5, 10, and 15% for the x, y, and z axes, respectively. 4.34 1.09 km3226Uncertainty is given as 25% 0.156 15.36 Sq-type7 8.76243 0.00004 h226 -31 5°226 281 5°226 (8567) 1996 HW 1 is a near-Earth asteroid (NEA) located in the inner Solar System. It was discovered on 23 April 1996 by astronomer Tom Gehrels at Steward Observatory. It is a contact binary asteroid, with two lobes separated by a distinct "neck"; altogether, the asteroid is on average 2 km mi in diameter. It has a rotation period of 8.76 hours, which is likely gradually slowing because of the YORP effect. Discovery 1996 HW 1 was discovered on 23 April 1996 by astronomer Tom Gehrels, who was working as a part of the Spacewatch survey at Steward Observatory, Arizona, United States. The asteroid was assigned the provisional designation 1996 HW 1 by the Minor Planet Center (MPC), and its discovery was published in a Minor Planet Circular on 2 May 1996.115 Once its orbit was sufficiently determined, it was given the minor planet number of 8567 by the MPC on 11 April 1998.56 2025, it remains unnamed. Orbit 1996 HW 1 orbits the Sun at an average distance—its semi-major axis—of 2.05 astronomical units (AU), with an orbital period of 2.93 years. It is classified as a near-Earth asteroid; because its orbit lies entirely outside Earth's orbit, it is also classified as an Amor asteroid. Along its orbit, its distance from the Sun varies between 1.13 AU at perihelion to 2.96 AU at aphelion due to its orbital eccentricity of 0.45. Its orbit is inclined by 8.45° with respect to the ecliptic plane. Physical characteristics 1996 HW 1 is a contact binary object with dimensions of 3.78 by 1.64 by 1.49 km mi217 and an equivalent mean diameter of 2.02 km mi.226 Its two lobes have an estimated mass ratio of 2:1, and are separated by a prominent neck.223, 217 Spectroscopic observations of 1996 HW 1 show that it is classified as an Sq-type asteroid, with spectral properties between S-type asteroids and Q-type asteroids.7 It has a geometric albedo of 0.156, though its visible light albedo is higher at approximately 0.33.231 Its spectrum is significantly reddened, indicating that its surface has undergone appreciable space weathering.7 Spin and evolution 1996 HW 1 has a sidereal rotation period of 8.76 hours, spinning in a retrograde direction with pole ecliptic coordinates of (281°, –31°). Its spin properties were derived from its lightcurve, or variations in its observed brightness, which was additionally supported by radar observations.212 Assuming a bulk density of 2.0 g/cm3, the asteroid is spinning slower than its minimum energy state of 7.4 hours, placing its neck under compressive and shear stress. A lower assumed density of 1.43 g/cm3 makes its observed rotation period its minimum energy state, but such a density requires an improbable porosity of 58%.222 1996 HW 1's spin is likely being slowed by the YORP effect, where irregularly shaped asteroids experience a torque as they emit thermal radiation. 1996 HW 1's faster rotation period in the past suggests that its two lobes originally may have been separated as a binary system. The YORP effect slowly removes angular momentum from binary asteroids, though how quickly this leads to the two components merging depends on the mass ratio. Given the mass ratio of 1996 HW 1's two lobes, they could have merged in a span of 1 million years (Myr), within the typical 10 Myr dynamical lifetimes of NEAs.222–223 Notes References 2023-02-18 last obs. JPL Small-Body Database Lookup: 8567 (1996 HW1) https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=8567 Jet Propulsion Laboratory 17 November 2025 (8567) = 1996 HW1 https://www.minorplanetcenter.net/db_search/show_object?object_id=8567 Minor Planet Center 15 November 2025 live (5331 obs) M. P. C. 26947–27146 https://minorplanetcenter.net/iau/ECS/MPCArchive/1996/MPC_19960503.pdf Minor Planet Circulars Minor Planet Center 3 May 1996 26947–27146 16 November 2025 M. P. C. 31457–31632 https://minorplanetcenter.net/iau/ECS/MPCArchive/1998/MPC_19980411.pdf Minor Planet Circulars Minor Planet Center 11 April 1998 31457–31632 16 November 2025 NEO Groups NASA/JPL Near-Earth Object Program Office http://neo.jpl.nasa.gov/neo/groups.html https://web.archive.org/web/20020202160655/http://neo.jpl.nasa.gov/neo/groups.html dead 2002-02-02 2012-06-04 Asteroid 8567 1996 HW1 NASA 21 April 2025 https://science.nasa.gov/3d-resources/asteroid-8567-1996-hw1/ 16 November 2025 https://web.archive.org/web/20250515091900/https://science.nasa.gov/3d-resources/asteroid-8567-1996-hw1/ 15 May 2025 Magri Christopher et al. Radar and photometric observations and shape modeling of contact binary near-Earth Asteroid (8567) 1996 HW 1 July 2011 Icarus 214 1 210–227 10.1016/j.icarus.2011.02.019 2011Icar..214..210M Popescu M. Birlan M. Binzel R. Vernazza P. Barucci A. Nedelcu D. A. DeMeo F. Fulchignoni M. Spectral properties of eight near-Earth asteroids November 2011 Astronomy & Astrophysics 535 A15 10.1051/0004-6361/201117118 2011A&A...535A..15P Howell E. S. et al. SHERMAN – A shape-based thermophysical model II. Application to 8567 (1996 HW1) March 2018 Icarus 303 10.1016/j.icarus.2017.12.003 2018Icar..303..220H External links 8567 8567 (8566) 1996 EN 8567 (8567) 1996 HW 1 8568 Larrywilson 008567 008567 008567 19960423 008567