Are Supernovae Recorded in Indigenous Astronomical Traditions?
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Journal of Astronomical History and Heritage, 17(2), 161–170 (2014). ARE SUPERNOVAE RECORDED IN INDIGENOUS ASTRONOMICAL TRADITIONS? Duane W. Hamacher Nura Gili Indigenous Programs Unit University of New South Wales, Sydney, NSW, 2052, Australia. Email: [email protected] Abstract: Novae and supernovae are rare astronomical events that would have had an influence on the sky- watching peoples who witnessed them. Although several bright novae/supernovae have been visible during recorded human history, there are many proposed but no confirmed accounts of supernovae in indigenous oral traditions or material culture. Criteria are established for confirming novae/supernovae in oral traditions and material culture, and claims from around the world are discussed to determine if they meet these criteria. Aboriginal Australian traditions are explored for possible descriptions of novae/supernovae. Although representations of supernovae may exist in Aboriginal traditions, there are currently no confirmed accounts of supernovae in Indigenous Australian oral or material traditions. Keywords: Historical astronomy, ethnoastronomy, cultural astronomy, Aboriginal Australians, novae, supernovae. 1 INTRODUCTION cide with a death in the community, or the appear- ance of a comet or eclipse might coincide with a Like many indigenous cultures around the world, famine, drought or battle (Johnson, 1998: 86– Aboriginal Australians possess detailed know- 89). ledge of the night sky, using it for navigation, calendars and time-keeping, food economics, 2 NOVAE AND SUPERNOVAE ceremonies and social structure (e.g. Cairns and Harney, 2003; Fredrick, 2008; Hamacher Novae are stellar explosions that occur in white and Norris, 2011a; Johnson, 1998). This sky dwarf stars that are members of binary systems. knowledge involves an understanding and ex- When the companion star (generally a main se- planation of planetary motions, relative stellar quence star or a red giant) expands, ejected positions, lunar phases and tides, and the pos- gas fills its Roche Lobe and overflows into the ition of the rising and setting Sun throughout the Roche Lobe of the white dwarf, forms an ac- year with respect to the landscape (Hamacher cretion disk and settles on the surface of the and Norris, 2011a; Norris and Hamacher, 2009; white dwarf. Eventually conditions (e.g. pressure Norris et al., 2013). This knowledge includes and temperature) are right to ignite a thermo- explanations of transient phenomena, such as nuclear explosion in the accumulated surface meteors, comets, eclipses and aurorae (Hama- layer, causing a nova outburst. This event may cher and Norris, 2010; 2011b; 2011c; and Ham- be visible to us and seen with the naked eye for acher, 2013, respectively). This sky knowledge periods ranging from days to weeks. has been passed down through successive A supernova is the explosion of a star, and is generations in the form of oral traditions and one of the most violent events in the Universe. material culture (Clunies-Ross, 1986). The energy released during a supernova ex- Indigenous astronomical traditions contain plosion is up to 10 billion times the star‘s normal scientific information that explains the natural energy output. These events can occur in one world in terms of cause-effect. This scientific of two primary ways: (1) A compact star, such information was based on observation and de- as a white dwarf, accretes enough material to exceed the Chandrasekhar limit (~1.4 M ). Its duction and was used for predictive purposes. Indigenous Australians linked lunar phases to core temperature then reignites nuclear fusion, tides and used this information as a guide for causing a runaway reaction that leads to a supernova; and (2) If a massive star (>8 M ) deciding when to fish, and their traditions con- tained an explanation as to how and why the undergoes core collapse, it will release a tre- Moon was connected to tides (e.g. Johnson, mendous amount of potential gravitational ener- 1998: 27, 37). The heliacal rising of the Pleiades gy, blowing the outer layers of the star into signalled the arrival of winter in the Central space at speeds approaching 10% the speed of Desert (Tindale, 2005: 374), while the rising of light. A supernova can release as much energy the celestial emu after dusk informed Aboriginal in a month as our Sun does in 10 billion years. people that emu eggs were ready to be collect- Supernovae can outshine entire galaxies and ed (e.g. Fuller et al., 2014). Similarly, transient may be visible to the naked eye for a period ranging from weeks to years. phenomena, whether rare or common, are often linked to special events on the Earth. For ex- Both novae and supernovae form shells of ample, the sudden flash of a meteor may coin- heated material that are ejected into space. Page 161 Duane Hamacher Supernovae and Indigenous Astronomical Traditions Those formed from novae are much less novae recorded over the last 2,000 years, plus a massive and have a lifetime of a few hundred few bright supernovae that are believed to have years. Supernova remnants have much longer been visible before this time, is given in Table 1 lifetimes and will expand into the surrounding in order of age (oldest to youngest). medium for hundreds to thousands of years Most of these records were taken from cult- before slowing to local speeds. The interested ures in the northern hemisphere. Since a signif- reader is directed to Arnett (1996) for an in- icant portion of the galactic plane, and the Large depth discussion of supernovae physics. and Small Magellanic Clouds, are only visible at Bright novae and supernovae would have more southerly latitudes, some bright super- novae were not recorded by literate cultures. had an impact on the people and cultures that witnessed them. Several have been visible to Since indigenous cultures around the world the naked eye over the last few thousand years, were keen observers of the night sky (Ruggles, some of which appeared brighter than the bright- 2011), we expect to find descriptions of novae/ est stars. Yet accounts of these events in oral supernovae in indigenous oral or material cult- (non-literate) cultures around the world remain ure. Many claims of these records have been scant in the literature. made. The next section establishes criteria for confirming these accounts, and is followed by a 3 HISTORICAL NOVAE AND SUPERNOVAE brief survey of novae/supernovae claims from around the world. Finally, we analyse an oral Seven bright novae (mV = +2 or brighter) have 1 tradition from Australia that describes the appear- been visible from Earth since 1890. Only one ance of a bright new star in the sky. —V603 Aquilae—rivalled Sirius (Alpha Canis Majoris, mV = –1.46) in brightness, reaching a 4 IDENTIFYING NOVAE AND SUPERNOVAE visual magnitude (mV) of –1.4 in 1918 (Harrison IN INDIGENOUS CULTURAL TRADITIONS et al., 2013). Nine supernovae are known to have been visible to the naked eye in the last Since transient celestial phenomena, such as 2,000 years (Green, 2002), seven of which had comets, meteors and eclipses, are recorded in an apparent magnitude of 0 or brighter (see oral and material traditions by cultures around Table 1). the world, it is likely that supernovae were also recorded. But identifying a clear example is dif- Supernovae are generally named after the ficult, as two main problems impede our ability year in which they were visible (or believed to to directly associate an oral tradition or art form have been visible). For example, a supernova with a particular supernova event: (1) descript- that appeared in the year 1054 CE is named tions in oral traditions are generally ambiguous; ‗SN 1054‘. Recorded supernovae visible to the and (2) motifs in material culture are sometimes naked eye appear roughly once every 250 years open to interpretation. Because of this, misident- on average. Historical supernovae have been ifications and misinterpretations of supernovae- recorded by literate cultures such as the Chin- in-culture are common. This necessitates a list ese, Koreans and Romans (Chu, 1968; Clark of criteria required to confirm a nova/supernova and Stephenson, 1982; Shen, 1969; Stothers, in oral traditions (O), material culture (M) or both 1977). A list of currently-known bright super- (OM): Table 1: Known bright (minimum mV = 2.0) supernovae since 1 CE, plus five supernovae known to have been visible during human (pre)history. Name Location RA Dec mV D (ly) Type Age Vela Vela 08h 34m −45° 50′ −10 ? 815±98 - 11000-12300 BP Veil Cygnus 20h 45m +30° 42′ 1470 - ~5000 BP HB9 Auriga 05h 01m +46° 40‘ 2608±1304 4000-7000 BP Puppis A Puppis 08h 24m −42° 59' −1.4 ? 7000 - ~3700 BP E0102-72 Tucana 01h 04m −72° 01′ +2 190000 - 1000–2650 BP RX J0852.0-4622 Vela 08h 52m −46° 22' 700? - 680-1100 BP SN 185 Circinus 14h 43m −62° 30′ < −8 ? 8200 Ia(?) 185 CE SN 386 Sagittarius 18h 14m −19° 46′ +1 14700 II 386 CE SN 393 Scorpius 17h 14m −39° 48′ −1 34000 - 393 CE SN 1006 Lupus 15h 02m −42° 06′ −7.5 7200 Ia 1006 CE SN 1054 Taurus 05h 35m +22° 01′ −4 6500 II 1054 CE SN 1181 Cassiopeia 02h 06m +64° 50′ −1 8500 - 1181 CE SN 1572 Cassiopeia 00h 25m +64° 09′ −4 8000 Ia 1572 CE SN 1604 Ophiuchus 17h 30m −21° 29′ −2.5 14000 Ia 1604 CE Notes: The peak magnitude of RX is not known, as its distance is controversial. The data are shown in order of age, citing their designation, age or year discovered (CE = Common Era, BP = Before Present), current home constellation, celestial coordinates (right ascension and declination in J2000 from SIMBAD: http://simbad.u-strasbg.fr), and the peak visual magnitude, if known (there is some uncertainty in these estimates—the values provided are estimates only).