Scientists map asteroid linked to meteor shower using new imaging technique
Researchers have created a detailed 3D shape model of an asteroid called 2005 UD, revealing it may be a fragment of Phaethon, which produces the Geminid meteor shower. The findings could improve predictions of asteroid behavior and inform planetary defense strategies as space agencies worldwide track near-Earth objects.
Originaltitel: Implications for the Formation of (155140) 2005 UD from a New Convex Shape Model
Ny 3D-modell av asteroiden (155140) 2005 UD clarifierar dess ursprung och möjliga koppling till den aktiva asteroiden Phaethon — två himlakroppar med liknande banor som kan ha delats från en gemensam föregångare. Forskare från Lowell Observatory och University of Arizona använde ljuskurveinversion på observationsdata från 2005–2021 för att bestämma rotationsperioden (5,234246 ± 0,000097 timmar) och härleda en konvex formmodell. Två lika väl passande polorienteringar identifierades; en överensstämmer med tidigare analyser, medan den andra ligger nära Phaethons polposition. Övervakningar för stoftproduktion gav en övre gräns på 0,04–0,37 kg/s, vilket tyder på minimal eller ingen aktivitet. Spinlösningarna begränsar nu möjliga scenarior för systemets fysiska utveckling, relevant för att förstå asteroiders dynamiska beteende och missionsplanering för asteroidstudie.
<p>(155140) 2005 UD has a similar orbit to (3200) Phaethon, an active asteroid in a highly eccentric orbit thought to be the source of the Geminid meteor shower. Evidence points to a genetic relationship between these two objects, but we have yet to fully understand how 2005 UD and Phaethon could have separated into this associated pair. Presented herein are new observations of 2005 UD from five observatories that were carried out during the 2018, 2019, and 2021 apparitions. We implemented light curve inversion using our new data, as well as dense and sparse archival data from epochs in 2005–2021, to better constrain the rotational period and derive a convex shape model of 2005 UD. We discuss two equally well-fitting pole solutions (λ = 116 6, β = −53 6) and (λ = 300 3, β = −55 4), the former largely in agreement with previous thermophysical analyses and the latter interesting due to its proximity to Phaethon's pole orientation. We also present a refined sidereal period of Psid = 5.234246 ± 0.000097 hr. A search for surface color heterogeneity showed no significant rotational variation. An activity search using the deepest stacked image available of 2005 UD near aphelion did not reveal a coma or tail but allowed modeling of an upper limit of 0.04–0.37 kg s−1 for dust production. We then leveraged our spin solutions to help limit the range of formation scenarios and the link to Phaethon in the context of nongravitational forces and timescales associated with the physical evolution of the system.</p>