Three Astronomical Images

Observatory / Course Archives / ASTR 110 Fall 2019 / Powlison

Exoplanet PDS 70b: Carving Out Star PDS 70's Accretion Disk

Surrounding PDS 70 is its protoplanetary disk, and in that disk lies a planet, PDS 70b. At first, Miriam Keppler speculated that the planet could've been a mistake made by telescope, but upon careful inspection, the planet consistently showed evidence of its existence. With new observational breakthroughs, scientists are able to more clearly see PDS 70b. Its mass is a few times larger than Jupiter, and its surface temperature is around 1000°C, making it a gas giant. The extraordinary thing about PDS 70b is that it is first time we've been able to see a planet form (it's very young!).

The dark circle (coronagraph) at the center of the image was created by scientists to mask the light coming from PDS 70, so that we can see the really cool exoplanet orbiting it. Scientists have found PDS 70b to be 22 AU away from its host star (that's really close!), and creates a large cavity in the dust disk around the star, measuring up to ~60 AU! This puzzles scientists, because PDS 70b's close proximity to its host star and its creation of such a large cavity doesn't make sense.

Southern Crab Nebula (Hen 2-104): A Shedding Red Giant and its Partner Dwarf Star

The Southern Crab Nebula (Hen 2-104) can be found only a few thousand light years away, in the constellation Centaurus. It looks like an hourglass, due to it being a binary system. The white dwarf is able to pull ejected material from its neighbor, thus forming a rather interesting shape and color. Colors are caused by reactions with hydrogen, sulfur, nitrogen, and oxygen.The color appears brightest at the edges, giving the nebula its name. Astronomers think that the coloration comes from collisions with external stellar dust.This particular image was used as a celebration of Hubble's 29th anniversary since it's launch.

The nebula consists of a burning-out Red Giant and a white dwarf star. The Red Giant is “shedding” its outer layers, which are subsequently swallowed up by its companion dwarf star. The main "donor" for the mass of the nebula is speculated to be the Mira. This gives us the shape of the nebula; the slower Mira winds collide with the faster stellar winds from the white dwarf star, causing a circum-binary nebula. Few of these nebulae have been discovered.

NGC 3147: A Galaxy with a Supermassive Black Hole that Shouldn't Exist

NGC 3147 has a mysterious story. What's so spectacular about NGC 3147 is that at the center, a "malnourished" black hole's gravity continuously pulls in anything that comes near it, adding to it's disk. Its “graceful, winding arms” were found to be large stretches of young blue stars, dust, and pink nebulas. The galaxy is located in the constellation Draco the Dragon.

Located 130 million light years away, NGC 3147 was previously thought by astronomers to have a quiescent supermassive black hole, however they discovered that it was actually "feeding off of" an accretion disk. The mystery is that when a black hole has a disk, there is usually a light it produces called a quasar, which is not shown in this galaxy. Scientists are still puzzled as to why the galaxy's black hole has a disk.