Welcome back to Messier Monday! Today, we continue in our homage to our dear pal, Tammy Plotner, by taking a look at the “little dumbbell” itself, the planetary nebula referred to as Messier 76!
Throughout the 18 th century, renowned French astronomer Charles Messier discovered the existence of a number of “ambiguous things” while surveying the night sky. Initially misinterpreting these things for comets, he started to brochure them so that others would not make the very same error. Today, the resulting list (referred to as the Messier Brochure) consists of over 100 things and is among the most prominent brochures of Deep Area Objects.
Among these things is the Messier 76 (aka. the Little Dumbbell Nebula, the Barbell Nebula, or the Cork Nebula) a planetary nebula situated about 2,500 light years away in the Perseus Constellation While it is simple to discover due to the fact that of its distance to the Cassiopeia Constellation(situated simply south of it), the faintness of this nebula makes it among the harder Messier Challenge observe.
Found some 2,500 light years far from Earth, the shell of this passing away star broadens over area for a range of about 1.23 light years– yet the halo around it continues for near to another12 Inside is a 16.6 magnitude main star, burning away at a temperature level of roughly 60,000 K!
One day, possibly in another 30 billion years, it will cool off a bit, ending up being a white dwarf star. However simply what makes its shape– its shape? As Toshiya Ueta of the NASA Ames Proving ground stated in a 2006 research study:
” We provide the far-infrared (IR) maps of a bipolar planetary nebula (PN), NGC 650, at 24, 70, and 160 [nanometers], taken with the Multiband Imaging Photometer for Spitzer (MIPS) on board the Spitzer Area Telescope. While the two-peak emission structure seen in all MIPS bands recommends the existence of a near edge-on dirty torus, the unique emission structure suggests the existence of 2 unique emission parts in the main torus. Based upon the spatial connection of these 2 far-IR emission parts with regard to different optical line emission, we conclude that the emission is mostly due to the [O IV] line occurring from extremely ionized areas behind the ionization front, whereas the other emissions are because of dust continuum occurring from low-temperature dust in the remnant asymptotic huge branch (AGB) wind shell. The far-IR nebula structure likewise recommends that the improvement of mass loss at the end of the AGB stage has actually taken place isotropically, however has actually taken place just in the equatorial instructions while stopping in the polar instructions. Today information likewise reveal proof for the prolate spheroidal circulation of matter in this bipolar PN. The AGB mass-loss history rebuilded in this PN is hence constant with what has actually been formerly proposed based upon the previous optical and mid-IR imaging studies of the post-AGB shells.”
So it’s bi-polar– simply another insane planetary nebula. However could it be blowing bubbles? According to some scientists, it could. These consist of M. Bryce (et al), who showed the following in a 1996 research study:
” High spatial and spectral resolution observations of the H?, [N II]6584 A and [O III]5007 A emission line profiles from the planetary nebula NGC 650 -1 have actually been acquired with the Isaac Newton and William Herschel Telescopes utilizing the Manchester echelle spectrometer. These observations, and extra narrow-band images acquired utilizing the San Pedro Martir telescope, are compared to synthesised images and spectra based upon the generalised connecting excellent winds (GISW) designs (including a sluggish wind highly focused towards the equatorial aircraft) and an excellent correspondence is discovered, verifying NGC 650 -1 to be a bipolar wind-driven bubble orientated at a disposition of ~75 deg with the NW lobe pointing towards the observer. There is an intense main ring with 2 connected (inner) lobes, which reveal normal growth speeds of ~43 km/s and ~60 km/s respectively. Outside the inner lobes are the fainter external lobes which are observed to have an extremely low growth speed (~ 5km/s), and which have on one side (SE) a polar cap which reveals greater speeds once again (~20 km/s). The nature of these external lobes stays uncertain.”
History of Observation:
Something is extremely clear– this faint shell was found by Pierre Mechain on the night September fifth,1780 He then handed it over to Charles Messier, who observed it, identified its position and included it to his brochure as things #76 on October 21 st, 1780.
” Nebula at the ideal foot of Andromeda, seen by M. Mechain on September 5, 1780, and he reports: “This nebula includes no star; it is little and faint”. On the following October 21, M. Messier tried to find it with his achromatic telescope, and it appeared to him that it was made up of absolutely nothing however little stars, including nebulosity, which the least light used to light up the micrometer wires triggers it vanish: its position was figured out from the star Phi Andromedae, of 4th magnitude.”
In 1787, Sir William Herschel would independently study Mechain’s discover and be the very first to see a double type: “2 nebulae close together. Both extremely intense. Range 2 ′. One is south preceding and the other north following. One is 76 of the Connoissance.” Because that time, a lot of observers view 2 unique areas and possibly a lot more? Simply ask historic astronomer, Admiral Smyth:
” An oval pearly white nebula, almost half-way in between Gamma Andromedae and Delta Cassiopeiae; near to the toe of Andromeda, though figured in the precincts of Perseus. It patterns north and south, with 2 stars preceding by 11 s and 50 s, and 2 following almost on the very same parallel, by 19 s and 36 s; and simply np of it is the double star above signed up, of which A is 9 magnitude, white; and B 14, dusky. When initially found, Mechain considered it a mass of nebulosity; however Messier believed it was a compressed cluster; and William Herschel that it was an irresolvable double nebula. It has an extremely abundant area, and with its buddies, was carefully viewed in my observatory, as a gauge of light, throughout the overall eclipse of the moon, on the 13 th of October, 1837, being extremely well seen throughout the darkness, and slowly fading as the moon emerged. In 1842, I spoke with Mr. Challis upon the meaning of this nebula in the terrific Northumberland equatorial, and he responded: “I took a look at the nebula, as you preferred, and believed it had a sprangled look. The resolution, nevertheless, was extremely uncertain.”
Finding Messier 76:
Since this planetary nebula is little and faint, it isn’t an excellent binocular target and will need dark skies even for a telescope. The simplest method to discover the M76 is to begin with the 3.5 magnitude star 51 Andromedae and make you method about a finger width (2 degrees) north-northeast till you pertain to fourth- magnitude Phi Persei, a variable star. From here intend your telescope less than a degree northwest of the star, and you will have M76 in the eyepiece field of vision.
In a little telescope, you’ll see an unique, odd-shaped radiance that will handle more structure and type as aperture boosts. Large telescopes will not just see double lobed structure, however the extra faint halo ring too. Not for light contaminated skies or moonlit nights!
Things Call: Messier 76
Alternative Classifications: M76, NGC 650/651, Little Dumbbell Planetary, Cork Nebula, Butterfly Nebula, and Barbell Nebula
Things Type: Planetary Nebula
Right Ascension: 01: 42.4 (h: m)
Declination: +51: 34 (deg: m)
Range: 3.4 (kly)
Visual Brightness: 10.1 (mag)
Evident Measurement: 2.7 × 1.8 (arc minutes)
We have actually composed numerous fascinating short articles about Messier Objects and globular clusters here at Universe Today. Here’s Tammy Plotner’s Intro to the Messier Items, M1– The Crab Nebula, Observing Spotlight– Whatever Occurred to Messier 71?, and David Dickison’s short articles on the 2013 and 2014 Messier Marathons.