Apollo asteroid 2005 UD: split nucleus of (3200) Phaethon?

Ohtsuka, K.; Sekiguchi, T.; Kinoshita, Daisuke; Watanabe, J.; Itô, Takashi; Arakida, Hideyoshi; Kasuga, Toshihiro

doi:10.1051/0004-6361:200600022

Cited by 90 publications

(98 citation statements)

References 23 publications

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“…However, the difference in orbital secular angles (longitudes of node and perihelion) precludes their separation from Phaethon in the immediate past (see also Ohtsuka et al 2006), but rather ∼100 kyr ago or, more likely, even before this epoch. The obliquity of the preferred spin solution exhibits stable oscillations about the mean value ∼148 • with typically a small amplitude of ∼10 • , much lower than the orbit inclination.…”

Section: Discussionmentioning

confidence: 99%

Near-Earth asteroid (3200) Phaethon: Characterization of its orbit, spin state, and thermophysical parameters

Hanuš

Delbò

Vokrouhlický

et al. 2016

A&A

110

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Context. The near-Earth asteroid (3200) Phaethon is an intriguing object: its perihelion is at only 0.14 au and is associated with the Geminid meteor stream. Aims. We aim to use all available disk-integrated optical data to derive a reliable convex shape model of Phaethon. By interpreting the available space-and ground-based thermal infrared data and Spitzer spectra using a thermophysical model, we also aim to further constrain its size, thermal inertia, and visible geometric albedo. Methods. We applied the convex inversion method to the new optical data obtained by six instruments and to previous observations. The convex shape model was then used as input for the thermophysical modeling. We also studied the long-term stability of Phaethon's orbit and spin axis with a numerical orbital and rotation-state integrator.Results. We present a new convex shape model and rotational state of Phaethon: a sidereal rotation period of 3.603958(2) h and ecliptic coordinates of the preferred pole orientation of (319 • , −39 • ) with a 5 • uncertainty. Moreover, we derive its size (D = 5.1 ± 0.2 km), thermal inertia (Γ = 600 ± 200 J m −2 s −1/2 K −1 ), geometric visible albedo (p V = 0.122 ± 0.008), and estimate the macroscopic surface roughness. We also find that the Sun illumination at the perihelion passage during the past several thousand years is not connected to a specific area on the surface, which implies non-preferential heating.

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Section: Discussionmentioning

confidence: 99%

Near-Earth asteroid (3200) Phaethon: Characterization of its orbit, spin state, and thermophysical parameters

Hanuš

Delbò

Vokrouhlický

et al. 2016

A&A

110

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“…The Geminid meteoroids show extreme diversity in their Na abundance, from strong depletion to near Sun-like Na content (Harvey 1973;Borovička et al 2005;Kasuga et al 2005). Presumably, this compositional diversity reflects different thermal modification on Phaethon (or perhaps the larger sized precursor body) itself Kasuga et al 2006;Ohtsuka et al 2006;Kasuga & Jewitt 2008;Capek & Borovička 2009;Kasuga 2009;Ohtsuka et al 2009). For the Quadrantid meteoroids, the measured line intensity ratios show that Na is less depleted than in the majority of Geminid meteoroids (Koten et al 2006;Borovička et al 2010).…”

Section: Discussionmentioning

confidence: 99%

Physical Observations of (196256) 2003 Eh1, Presumed Parent of the Quadrantid Meteoroid Stream

Kasuga

Jewitt

2015

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The near-Earth asteroid (196256) 2003 EH1 has been suggested to have a dynamical association with the Quadrantid meteoroid stream. We present photometric observations taken to investigate the physical character of this body and to explore its possible relation to the stream. We find no evidence for ongoing mass loss. A model fitted to the point-like surface brightness profile at 2.1 AU limits the fractional contribution to the integrated brightness by the near-nucleus coma to 2.5%. Assuming an albedo equal to those typical of cometary nuclei (p R = 0.04), we find that the effective nucleus radius is r e = 2.0 ± 0.2 km. Time-resolved R-band photometry can be fitted by a two-peaked light curve having a rotational period of 12.650 ± 0.033 hr. The range of the light curve, Δm R = 0.44 ± 0.01 mag, is indicative of an elongated shape having an axis ratio of ∼1.5 projected into the plane of the sky. The asteroid shows colors slightly redder than the Sun, being comparable with those of C-type asteroids. The limit to the mass loss rate set by the absence of the resolved coma is 2.5 × 10 −2 kg s −1 , corresponding to an upper limit on the fraction of the surface that could be sublimating water ice f A  10 −4 . Even if sustained over the 200-500 year dynamical age of the Quadrantid stream, the total mass loss from 2003 EH1 would be too small to supply the reported stream mass (10 13 kg), implying either that the stream has another parent or that mass loss from 2003 EH1 is episodic.

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“…This object is dynamically associated with the Geminid meteor stream (e.g., Williams & Wu 1993) and with several other small asteroids including 2005 UD (Ohtsuka et al 2006;Konoshita et al 2007) and 1999 YC (Ohtsuka et al 2008;Kasuga & Jewitt 2008). All these objects may be related to a precursor body that disintegrated ∼10 3 yr ago (Ohtsuka et al 2006).…”

Section: Observations Of Active Asteroidsmentioning

confidence: 92%

The Active Asteroids

Jewitt

2012

The Astronomical Journal

286

244

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Some asteroids eject dust, unexpectedly producing transient, comet-like comae and tails. First ascribed to the sublimation of near-surface water ice, mass-losing asteroids (also called "main-belt comets") can in fact be driven by a surprising diversity of mechanisms. In this paper, we consider 11 dynamical asteroids losing mass, in nine of which the ejected material is spatially resolved. We address mechanisms for producing mass loss including rotational instability, impact ejection, electrostatic repulsion, radiation pressure sweeping, dehydration stresses, and thermal fracture, in addition to the sublimation of ice. In two objects (133P and 238P) the repetitive nature of the observed activity leaves ice sublimation as the only reasonable explanation, while in a third ((596) Scheila), a recent impact is the cause. Another impact may account for activity in P/2010 A2, but this tiny object can also be explained as having shed mass after reaching rotational instability. Mass loss from (3200) Phaethon is probably due to cracking or dehydration at extreme (∼1000 K) perihelion temperatures, perhaps aided by radiation pressure sweeping. For the other bodies, the mass-loss mechanisms remain unidentified, pending the acquisition of more and better data. While the active asteroid sample size remains small, the evidence for an astonishing diversity of mass-loss processes in these bodies is clear.

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Apollo asteroid 2005 UD: split nucleus of (3200) Phaethon?

Cited by 90 publications

References 23 publications

Near-Earth asteroid (3200) Phaethon: Characterization of its orbit, spin state, and thermophysical parameters

Near-Earth asteroid (3200) Phaethon: Characterization of its orbit, spin state, and thermophysical parameters

Physical Observations of (196256) 2003 Eh1, Presumed Parent of the Quadrantid Meteoroid Stream

The Active Asteroids

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