Taurus figure by H. A. Rey. Or, if you prefer, …

Taurus figure by H. A. Rey

Or, if you prefer, …

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

Aldebaran0.965 lyRed G

, zeta3.0415 ly

Elnath (. beta)1.7131 ly

Pleiades (M 45)370 ly

Hyades153 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

Visible (Palomar)

X-ray (CHANDRA)

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)

Observing M1

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”

118 Tau

Tau

Chi Tauri

118 Tauri

Open Clusters• NGC 1647: 6.2, 1800 ly• NGC 1746: 6.1, 1400 ly

NGC 1647

NCG 1746

NGC 1647

NGC 1746

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!)

Hind’s Variable Nebula & T Tau

Taurus Nebulosities

Crystal Ball Nebula

Crystal Ball Nebula

Variable StarsSky 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)

Finding Sh 2-240

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!

Red circle is a 2 FOV

The Stars

Magnitude Luminosity (Ls)

Mass (Ms) Radius (Rs)

Alcyone 2.9 2400 6 10

Atlas 3.6 940 5 6.8

Electra 3.7 1225 5 6

Maia 3.9 660 4.7 5.5

Merope 4.1 630 4.5 4.3

Taygeta 4.3 600 4.5 4.5

Pleione 5.1 190 3.4 3.2

Celaeno 5.5 270 3.7 3

(A)sterope 5.8 86 3 3.7

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

And of course there’s …

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

H-R diagram

Had enough yet?