An Outburst of Comet Schwassmann-Wachmann 1

Abstract

Comet Sch was smann-Wachmann 1, 1925 II, was discovered photographically at Bergedorf on November 15, 1927. At the time of discovery the comet was of magnitude 13 to 14, and had a distinct nucleus and a nearly circular coma some 2' in diameter. Even during the first few weeks after discovery, variability in the brightness was noted. In an interval of five days at the end of November, G. Van Biesbroeck noted a decrease in brightness of nearly two magnitudes. By late February 1928 the comet had faded to magnitude 17 or fainter and could no longer be observed as it approached conjunction with the sun. On September 21, 1928, following conjunction, W. Baade reobserved P/Schwassmann-Wachmann 1 at Bergedorf and reported the magnitude as 16.5.

Cometary Activity, Discrete Outgassing Areas, and Dust-Jet Formation

“…Travelling in a nearly circular orbit just beyond Jupiter, the comet is known to flare up frequently by a factor of 100 or more with respect to its quiescent-phase brightness. As described by Richter (1941Richter ( , 1954, Roemer (1958Roemer ( , 1962, Beyer (1962), Shao and Schwartz (1981), and others, the object appears absolutely stellar in the initial hours of an outburst. When observed photographically, the starlike condensation gradually expands into a disk or halo, which becomes diffuse with time and may display structure, sometimes of corkscrew shape.…”

“…Although their result is model-dependent, it is consistent with the observed expansion velocities at ~6 AU from the Sun. The time scales of two events, one observed photographically by Roemer (1958) in August-September 1957 and the other visually by Beyer (1962) in October 1959-January 1960, differ dramatically. According to Roemer, the comet regains its quiescent appearance within 3-4 weeks, unless the outburst is followed by continuing activity.…”

CO Gas and Dust Outbursts from Centaur 29P/Schwassmann–Wachmann

“…29P/SW1 is one of ∼ 30 known active Centaurs and is legendary for having a continuously present dust coma superimposed with explosive outbursts several times a year (See Table 1 and references on footnote a). The vast majority of its activity is documented with visible magnitudes, and most of the light at this wavelength comes from the reflection and scattering of sunlight off the dust particles in the coma, Roemer (1958); Roemer (1962); Whipple (1980); Jewitt (1990); ; Trigo-Rodríguez et al (2008); Ferrín (2010); Miles et al (2016); Schambeau (2018) b m helio is the apparent magnitude, m v , corrected for geocentric distance with equation 1, and is also referred to as m(1, r, θ), with smaller contributions from some ions and radicals . While small-scale changes in the lightcurve may be caused by nucleus rotation, largescale changes in 29P/SW1's visible magnitude are probably largely due to changes in quantity or types of dust production output, including explosive outbursts.…”

Comet P/2010 TO20 LINEAR-Grauer as a Mini-29P/SW1

“…The orbit of 29P is nearly circular (e = 0.04) with perihelion and semimajor axis beyond Jupiter (q = 5.7 au and a = 6.0 au), and obeys the dynamical definition of a Centaur. 29P is constantly active and displays sporadic photometric outbursts (Roemer 1958;Jewitt 1990;Trigo-Rodríguez et al 2008). The activity of 29P is mainly driven by carbon monoxide sublimation (Senay & Jewitt 1994;Crovisier et al 1995).…”