Taurus • 17th in size of the 88 constellations • 797 sq. degrees • 1.9% of the Celestial Sphere • When you look at Taurus, you’re looking away from the center of the Milky Way and slightly down, below the plane of the galaxy • galactic coordinates of Aldebaran: 181 °, -20° • Culminates on Dec. 3 (Aldebaran) • In about 2450 BC, at the Vernal Equinox
History • One of the oldest known constellations • Probably ancient when Ptolemy listed the 48 • Cave paintings at Lascaux (21,000 BP) – is this Taurus & the Pleiades?
Mythology • Disguise used by Zeus to woo Europa (“for the usual discreditable purposes”) • In the Zodiac, the Cretan Bull – one of the Twelve Labors of Herakles • Bull was dedicated to Bacchus, the Wine God – Hyades are dancing girls at his festival • The Pleiades have their own mythologies, in many different cultures – we’ll talk about that later
Overview Pleiades (M 45) 370 ly Elnath (. beta) 1.7 131 ly Hyades 153 ly Aldebaran 0.9 65 ly Red G , zeta 3.0 415 ly
Name this author … “What caused me to undertake the catalog was the nebula I discovered above the southern horn of Taurus on September 12, 1758, while observing the comet of that year…. This nebula had such a resemblance to a comet, in its form and brightness, that I endeavored to find others, so that astronomers would not confuse these same nebulae with comets just beginning to shine….”
So he began with M1 X-ray (CHANDRA) Visible (Palomar) IR (2MASS) Radio (NRAO)
M1 – a SNR • Supernova first observed by Chinese astronomers on July 4, 1054 (some fireworks!) near zeta Tauri • Type II Supernova remnant • Strong H lines in spectrum • 1046 J of energy released – 100X much energy as the Sun has emitted in its entire history • “After more than a year, it gradually became invisible” • 6,000 ly away • At center is a pulsar, a neutron star spinning at 30 times per second
Observing M1 • Magnitude 8.4, 6.0’ x 4.0’ • Challenge object in AL Binocular Messier Club for 35 & 50 mm binoculars • It’s close enough to us (about 6500 ly) that its continuing expansion is actually visible over time – about 0.2” per year (about 600 mi/sec)
Major Stars • Aldebaran - the Follower (of the Pleiades) • Magnitude 0.9 • 65 ly • Luminosity 360 Ls • Diameter 45 Rs • Red G star • Elnath (beta Tauri) – the Butting One • Magnitude 1.7 • 131 ly • Luminosity 600 Ls
Double Stars • Chi Tauri: 5.4 & 7.6, separation 19.6” • 118 Tauri: 5.5 & 6.8, separation 4.7” Tau 118 Tau
Open Clusters • NGC 1647: 6.2, 1800 ly • NGC 1746: 6.1, 1400 ly NCG 1746 NGC 1647
Nebulosities • Crystal Ball Nebula • NGC 1514, 10.9 • Hind’s Variable Nebula • NGC 1555, 1.5’ • Burnham’s Nebula, • No NGC, ?? • Struve’s Lost Nebula • NGC 1554, ?? • The last three are all around T Tauri (later!)
Variable Stars Sky Tools 3 lists 133 variable stars brighter than magnitude 12.0, 44 brighter than magnitude 6.0 Have fun!
T Tauri • The archetype of an important class of variable star • Only magnitude 13.5
T Tauri Stars • Very young stars (protostars) – still contracting, not yet on Main Sequence • Emission lines as well as absorption lines in their spectra – so surrounded by thin, hot gas • Eject 10-7 to 10-8 Ms of gas per year at speeds of about 180,000 mph • Luminosity changes irregularly on scales of a few days • Masses < about 3 Ms and ages 1 million years. • The Trapezium stars in Orion began this way
Finding T Tauri 1 eyepiece FOV
Finding T Tauri 1 eyepiece FOV
And for you imagers … • Sharpless 2-240 (Simeis 147)
The Pleiades • M 45 is so well-known it doesn’t need much explanation • You can find them on any clear night when it’s above the horizon, even in the city • So I’ll concentrate on the mythology and the astrophysics • Besides – they’re worth an evening by themselves!
Myths & Stories • Greek / Roman • Sometimes seen as a bunch of grapes. As they set in the west, Orion seems to be leaning forward (dangerously) in an attempt to pick them. Maybe he’s already had too much to drink? • Seven sisters, daughters of Atlas & Pleione • Alcyone (the most beautiful & brightest), Celaeno, Maja, Merope, Taygete, Sterope, Electra • When Orion once attempted to break into their home, Venus changed them into a flock of doves
Myths & Stories • Native American • Seven children who longed to wander amidst the stars. They lost their way. They huddle together to make sure they won’t be separated. The youngest cries from homesickness; she’s the dimmest of the seven. • Devil’s Tower (Wyoming) was created to protect seven maidens pursued by bears • Medieval European people saw them as a hen & chicks (England, Germany, Denmark, Russia) • Midnight culmination (Nov. 21) was identified with the Witches’ Sabbath
Myths & Stories • South Seas islanders (Society & Tonga group, Hervey group) • Matariki was a single star, so bright that the god Tane, in envy, took Aumea (our Aldebaran) and, along with Mere (our Sirius), chased Matariki, who took refuge in a stream. Mere drained all the water out of the stream and Tane hurled Aumea at Matariki, breaking him up into smaller pieces. • Tolkein named them Remmirath in The Hobbit
The Pleiades • At least 500 stars in the overall cluster • Nebulosity is bluish, indicating it’s a reflection nebula • No relative proper motion, so likely to be loosely bound by gravity • Will probably disperse over the next 200 My • 440 ly away • About 100 My old • A young cluster of hot, bright stars