A mini star factory lost in the sky

By Phil Plait | June 22, 2012 6:30 am

You’d think that with all our fancy equipment and technology, all the nearby galaxies in the Universe would’ve been spotted by now. But it turns out that’s not the case. Some galaxies are very faint — small, with few stars — making them tough to find even when relatively speaking they’re in our neighborhood.

So say hello to our newly-discovered neighbor, UGC 4597!

[Click to galactinate.]

UGC 4597 is a dwarf galaxy. Galaxies like our Milky Way have billions or hundreds of billions of stars, but dwarf galaxies have stars numbering in the millions. That’s why it remained undiscovered until just a few years ago — it turned up in a survey taken in 2008! Astronomers were looking for dwarf companions to the splashy spiral galaxy M81 located about 12 million light years away, and dinky UGC 5497 showed up.

The image above was taken by Hubble in late 2009. Of course, in this shot it looks obvious enough, but this only shows a teeny portion of the sky. Because it’s so close to us, the entire M81 group of galaxies covers an area of the sky something like 20 times the size of the full Moon — thousands of times the size of this diminutive dwarf. That’s how it remained undiscovered for so long.

The image is a combination of two separates shots, one in visible light and one in near-infrared. The stars look very blue, with very few being red. Without a third image taken in bluer light it’s hard to be completely sure, but the color here most likely means that most of these stars are young, created in a wave of star formation a few million years ago. Just above and to the right of center of the core of the galaxy is a reddish patch; I thought initially that might be a gas cloud of some sort, but now I suspect it’s a background galaxy. In the full-res version of the picture you can see dozens of distant galaxies littering the scene, typical for a Hubble picture. They’re most likely hundreds of millions and even billions of light years away, far, far in the background.

That bright star on the right and the fainter one on the left are probably stars in the foreground, in our own galaxy. Sometimes that fact gets me even more than the rich science of the galaxies themselves: the depth of time and space we see in images like this. Nearby objects like local stars, medium-distance objects like neighborhood galaxies, and then mind-crushingly distant galaxies so far away that the light we see from them left when the newest evolutionary invention on Earth were organisms with more than one cell!

Astronomy may be all about looking out into the Universe, but it’s the perspective on ourselves that always stirs my mind.

ESA/Hubble & NASA


Related Posts:

Desktop Project Part 16: A dinky galaxy with a big gas problem
M81, up close and personal
In galactic collisions, might makes right
Pump up the galaxy

CATEGORIZED UNDER: Astronomy, Pretty pictures

Comments (14)

  1. Inti

    Since we can see its individual stars, will every one of those stars get catalogued? Same question for all those faint background galaxies, there are so many, are they all charted?

    Another question: on the top-left area, we see two stars very close together, one blue, one orange. Are they a binary star? A single moving object that got caught in both shots? Or maybe Portals? :D

  2. Greg

    Is there a black hole in the center of that galaxy?

    What is the radiation environment over there? Is life possible on any planets orbiting those stars?

  3. That’s where it went. Sorry, that fell out of my pocket a few years ago, and I was wondering where it had got off to. :P

    @Greg (#2), I think that many of them do indeed have a central black hole. I recall reading an article in SciAm a while back discussing the enigma of these intermediate sized black holes, and how we had very little idea of how they formed and actually interact with the stars around them. Of course, I could be wrong, and these dwarf galaxies are held together by mutual attraction like a globular cluster… I’m not an astronomer after all, just some wiseguy on the internet…

    No idea about your other questions Greg.

    Inti (#1), that could just be two stars that line up (Spectroscopic binaries) as opposed to being an actual binary system. Although I like the idea of them being portals. :D

  4. Rob

    Maybe it’s just trying to grasp how many degrees of magnitude difference we’re looking at in the shot, but I’m curious to know the names and distances of the star in the foreground and that (I think it’s a spiral) galaxy just below and to the right of the star.

  5. Wzrd1

    IS it a “dinky little galaxy”? Or is it a stripped galaxy, where it lost any arms to galactic interactions, which triggered star births at the rate observed?
    That will be answered over time, as the course and orbit of that group is observed.

  6. Tom

    Hold on, I’m confused

    This galaxy has a UGC (Uppsala General Catalogue) number. The UGC was released in the early 1970s. And yet UGC 5497 “turned up in a survey taken in 2008″ What am I missing here?

  7. Torbjörn Larsson, OM

    Hey, that is practically countable! If I have to count 10 million stars, one for each second, every waking hour, it will take me … half a year.

    That tears it. “Dwarf” as in dwarf planet can still mean “too big for my car”.

  8. Tonya W

    Typo. The beginning of the paragraph starts with “UGC 4597″ and ends with UGC 5497.

  9. Rick Johnson

    UGC 5497 is correct, UGC 4597 is a probable spiral galaxy nearly 300 million light-years further away in Cancer, not far from M44, the Beehive Cluster. Transpositions are my bane as well as BA’s it appears.

    The UGC listed anything its authors thought looked like it could be a galaxy from visual inspection of the POSS plates. So if it was a faint fuzzy it got picked up. This also picked up globular star clusters like Palomar 3 and some planetary nebulae. In the case of UGC 5497 all it recorded was a round object 1.3 minutes of arc across. This says nothing about its true nature. It could have been a giant elliptical galaxy a billion light-years away. Until studied further it was just a faint round fuzzy in the UGC and other catalogs (PGC 029735, CGCG 313-005 and MCG +11-13-007 for examples of its other catalog entries). With thousands of these recorded and so few studying these apparently dime a dozen objects it’s no wonder its true nature is just now coming to light. Many more interesting objects are likely waiting discovering buried in the UGC and other similar catalogs.

    Looking at the red and blue POSS plates UGC 5497 is indeed far brighter in blue light than red so a very blue galaxy indeed. I’ve added it to my to image list for next year. Too low in the west for this year :(

  10. Brian Too

    Imagine, a tiny dwarf galaxy with only millions of stars in it.

    I wonder how many sentient species are to be found there, staring at the giant galaxies around them? Do they feel disadvantaged? Perhaps they are like genteel country squires, happy to shun the big city rat race? Or is any such perspective possible, given the impossibly large size of the universe and the places in it?

  11. Mike the Canadian

    Brian Too:

    Not many, if any, sentient species are going to be found in the dwarf galaxy unless they are just visiting. He said that most of the stars are likely millions of years old so its unlikely there has been time for planets to cool and grow life.

    But it was the very first thing I thought, as well. :)

    “In the full-res version of the picture you can see dozens of distant galaxies littering the scene”
    I assume that from all the other galaxies in the picture, the odds are pretty damned good somebody is looking back at us.

    It simply boggles the mind, the number of stars in all the galaxies in our universe.

  12. Jon Hanford

    Just a minor clarification as to when the galaxy was “discovered”.

    The NASA PR seems to imply the galaxy was first noted in a 2008 study, whereas the paper, by Chiboucas et al, was the first to identify this galaxy as a member of the M 81 Group, a nearby small grouping of ~40 galaxies: http://arxiv.org/pdf/0805.1250v2.pdf

    Actually, UGC 5497’s listing in the “Uppsala General Catalog of Galaxies” dates to 1973 and NED and SIMBAD both list this galaxy as appearing in Vorontsov-Velyaminov’s 1962 “Morphological Galaxy Catalog” where it is listed as MCG +11-13-007: http://ned.ipac.caltech.edu/cgi-bin/nph-datasearch?search_type=Ref_id&objid=58501&objname=UGC%2005497&img_stamp=YES&hconst=73.0&omegam=0.27&omegav=0.73&corr_z=1&of=table

    So UGC 5497 was known to astronomers well before 2008, when its status as a dwarf galaxy residing in the M 81 Group was firmly established.

  13. Vw

    Thats a pretty amazing shot. I never really thought that a galaxy whose stars are resolvable for all ntents and purposes looked like a globular cluster, but I suppose it makes sense.

  14. Looks so much like a globular. Great photo and write-up , BA, Cheers!

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