Twilight discovery of the first known inner-Venus asteroid, (594913) ‘Ayló’chaxnim and naked-eye green comet C/2022 E3 at Palomar Observatory

Bryce Bolin

Near-Earth asteroid population models predict the existence of bodies located inside the orbit of Venus. Despite searches, up to the end of 2019, none had been found [1-4]. We report the discovery and follow-up observations of (594913) 'Ayló'chaxnim, the first known asteroid possessing an aphelion entirely within the orbit of Venus at Palomar Observatory. (594913) 'Ayló'chaxnim has an aphelion of ~0.65 au, is red in color, and is 2 km in diameter[5,6]. The detection of such a large asteroid inside the orbit of Venus is unexpected given their rarity according to near-Earth asteroid population models and the limited coverage of this region of the Solar System by ground-based surveys. Thus, 'Ayló'chaxnim may be a fluke, or asteroid population models may need to be revised. The prospects of finding more 'Ayló'chaxnim in ground-based surveys are discussed.  Comets, while often discovered in asteroid surveys,  present challenges for their detectability. Unlike asteroids, comets can have an extended appearance which can cause their detections to be confused with detector artifacts. We have developed a deep-learning network trained on images of comets capable of identifying comets on a per-image basis [7]. Between 2020-2022, ten comets were discovered at Palomar Observatory with this comet-identifying network [8]. On March 2, 2022, Long-period comet C/2022 E3 was discovered as an active comet as it crossed into the inner Solar System at 4.3 au from the Sun [9]. Reaching a brightness of V~5 at perihelion in late January 2023, the comet was seen by millions and observed by numerous observatories, C/2022 E3 around the globe. We discuss the details of the discovery of E3 as well as some of its characteristics such as volatile species and evolution in cometary appearance.  References: [1] Whiteley & Tholen 1998, Icarus, Volume 136, Issue 1, pp. 154-167. [2] Zavodny et al. 2008, Icarus, Volume 198, Issue 2, p. 284-293. [3] Denneau et al. 2013, PASP, Volume 125, Issue 926, pp. 357. [4] Vaduvescu et al. 2018, A&A, Volume 609, id.A105, 10 pp., [5] Bolin et al. 2020, Minor Planet Electronic Circ., No. 2020-A99., [6] Bolin et al. 2022, MNRAS, Volume 517, Issue 1, pp.L49-L54. [7] Duev et al. 2020, AJ, Volume 161, Issue 5, id.218, 8 pp., [8] Bolin et al., in prep. [9] Bolin et al. 2022, Minor Planet Electronic Circ., No. 2022-F13. 


This talk will be given in the Rubin Science Medley session.


Career Stage: 
Post Doc