Uninterrupted optical light curves of main-belt asteroids from the K2 Mission

Abstract

Due to the failure of the second reaction wheel, a new mission was conceived for the otherwise healthy Kepler space telescope. In the course of the K2 Mission, the telescope is staring at the plane of the Ecliptic, hence thousands of Solar System bodies cross the K2 fields, usually causing extra noise in the highly accurate photometric data. In this paper we follow the someone's noise is another one's signal principle and investigate the possibility of deriving continuous asteroid light curves, that has been unprecedented to date. In general, we are interested in the photometric precision that the K2 Mission can deliver on moving Solar System bodies. In particular, we investigate space photometric optical light curves of main-belt asteroids. We study the K2 superstamps covering the M35 and Neptune/Nereid fields observed in the long cadence (29.4-min sampling) mode. Asteroid light curves are generated by applying elongated apertures. We use the Lomb-Scargle method to find periodicities due to rotation. We derived K2 light curves of 924 main-belt asteroids in the M35 field, and 96 in the path of Neptune and Nereid. The light curves are quasi-continuous and several days long. K2 observations are sensitive to longer rotational periods than usual ground-based surveys. Rotational periods are derived for 26 main-belt asteroids for the first time. The asteroid sample is dominated by faint (>20 mag) objects. Due to the faintness of the asteroids and the high density of stars in the M35 field, only 4.0% of the asteroids with at least 12 data points show clear periodicities or trend signalling a long rotational period, as opposed to 15.9% in the less crowded Neptune field. We found that the duty cycle of the observations had to reach ~60% in order to successfully recover rotational periods.

9 pages, 9 figures, 6 tables, to be published in Astronomy and Astrophysics, for the full tables of observed asteroids and their rotational parameters see http://www.konkoly.hu/KIK/data_en.html

References in corpus (5)

• The K2 Mission: Characterization and Early results
• A Study of the Shortest-Period Planets Found With Kepler
• The heart of the swarm: K2 photometry and rotational characteristics of 56 Jovian Trojan asteroids
• Main-Belt Asteroids in the K2 Engineering Field of View
• Pushing the limits: K2 observations of the trans-Neptunian objects 2002 GV31 and (278361) 2007 JJ43

Cited by in corpus (10)

• The heart of the swarm: K2 photometry and rotational characteristics of 56 Jovian Trojan asteroids
• Photometric survey, modelling, and scaling of long-period and low-amplitude asteroids
• Thermal properties of slowly rotating asteroids: Results from a targeted survey
• 101 Trojans: a tale of period bimodality, binaries, and extremely slow rotators from K2 photometry
• The determination of asteroid H and G phase function parameters using GAIA DR2
• $V$-band photometry of asteroids from ASAS-SN: Finding asteroids with slow spin
• Shape models and spin states of Jupiter Trojans: Testing the streaming instability formation scenario
• Light curves of transneptunian objects from the K2 mission of the Kepler Space Telescope
• Identification of asteroids using the Virtual Observatory: the WFCAM Transit Survey
• Determination of rotation periods for a large sample of asteroids from K2 Campaign 9