Astronomy Picture of the Day |
APOD: 2007 June 9 - Globular Star Cluster M3
Explanation:
This immense ball of half a million stars older than the Sun lies
over 30,000 light-years away.
Cataloged as M3
(and NGC 5272),
it is one of about 150
globular star
clusters that roam the halo of our
Milky
Way Galaxy.
Even in this
impressively
sharp image, individual stars are difficult to distinguished in the
densely
packed core, but colors are apparent for the bright stars on the
cluster's outskirts.
M3's many cool "red" giant stars take on a yellowish cast,
while hotter giants and pulsating
variable stars look light blue.
A closer look
at the deep telescopic view also reveals a host
of background galaxies.
Itself about 200 light-years across, the giant star cluster is
a relatively bright, easy target for binoculars
in the northern constellation Canes Venatici,
The
Hunting Dogs, and not far from
Arcturus.
APOD: 2007 April 15 - M3: Inconstant Star Cluster
Explanation:
Star clusters appear constant because photographs of
them are frozen in time.
In reality, though,
cluster stars
swarm the center and frequently fluctuate in brightness.
Although the time it takes for stars to
cross a cluster is about 100,000 years,
the time it takes for a star to fluctuate noticeably
can be less than one night.
In fact, the above time lapse movie of bright
globular cluster
M3 was taken over a single night.
Most of the variable stars
visible above are
RR Lyrae stars, stars that can quickly double their
brightness while becoming noticeably bluer.
Furthermore, RR Lyrae stars vary their light in a distinctive pattern
that allows unique identification.
Lastly, since RR Lyrae stars all have the same intrinsic brightness,
identifying them and measuring how dim they appear
tells how far they are, since
faintness means farness.
These distances, in turn, help calibrate the
scale of the entire universe.
APOD: 2006 March 12 - Globular Cluster M3 from WIYN
Explanation:
This huge ball of stars predates our Sun.
Long before humankind evolved, before
dinosaurs roamed,
and even before our Earth existed, ancient globs of
stars condensed and orbited a young
Milky Way Galaxy.
Of the
200 or so
globular clusters that survive today,
M3
is one of the largest and brightest,
easily visible in the Northern hemisphere with binoculars.
M3
contains about half a million stars,
most of which are old and red.
Light takes about 35,000 years to reach us from
M3,
which spans about 150
light years.
The above picture is a composite of blue and red images.
APOD: 2004 October 12 - M3: Inconstant Star Cluster
Explanation:
Star clusters appear constant because photographs of
them are frozen in time.
In reality, though,
cluster stars
swarm the center and frequently fluctuate in brightness.
Although the time it takes for stars to
cross a cluster is about 100,000 years,
the time it takes for a star to fluctuate noticeably
can be less than one night.
In fact, the above time lapse movie of bright
globular cluster
M3 was taken over a single night.
Most of the variable stars
visible above are
RR Lyrae stars, stars that can quickly double their
brightness while becoming noticeably bluer.
Furthermore, RR Lyrae stars vary their light in a distinctive pattern
that allows unique identification.
Lastly, since RR Lyrae stars all have the same intrinsic brightness,
identifying them and measuring how dim they appear
tells how far they are, since
faintness means farness.
These distances, in turn, help calibrate the
scale of the entire universe.
APOD: 2003 September 15 - Globular Cluster M3
Explanation:
This huge ball of stars predates our Sun.
Long before humankind evolved, before
dinosaurs roamed,
and even before our Earth existed, ancient globs of
stars condensed and orbited a young
Milky Way Galaxy.
Of the
200 or so
globular clusters that survive today,
M3
is one of the largest and brightest,
easily visible in the Northern hemisphere with binoculars.
M3
contains about half a million stars,
most of which are old and red.
Light takes about 100,000 years to reach us from M3, which spans about 150
light years.
The above picture is a composite of blue and red images.
APOD: September 17, 1999 - M3: Half A Million Stars
Explanation:
This immense ball of half a million
stars older than the sun lies 30,000 light-years above
the plane of our Galaxy.
Cataloged as M3 (and
NGC 5272), it is one of about 250
globular star clusters which
roam our galactic halo.
Individual stars are difficult to distinguished in the
densely packed core but
colors are apparent for the bright stars on the
cluster's outskirts.
M3's many cool "red" giant stars take on a yellowish cast in
this lovely composite image while
hotter giants and pulsating variable stars look light blue.
APOD: July 19, 1998 - Globular Cluster M3
Explanation:
This huge ball of stars predates our Sun.
Long before mankind evolved, before dinosaurs roamed,
and even before our Earth existed, ancient globs of stars condensed
and orbited a young Milky Way Galaxy.
Of the 250
or so globular clusters
that survive today,
M3
is one of the largest and brightest, easily visible
in the Northern hemisphere with binoculars.
M3 contains about half a million stars, most of which are old and
red. The existence of young blue stars in M3 once posed a mystery,
but these blue stragglers are now thought to form via stellar interactions.
APOD: December 6, 1996 - Globular Cluster M3
Explanation: This huge ball of stars predates our Sun.
Long before mankind evolved, before dinosaurs roamed,
and even before our Earth existed, ancient globs of stars condensed
and orbited a young Milky Way Galaxy.
Of the 250
or so globular clusters
that survive today, M3
is one of the largest and brightest, easily visible
in the Northern hemisphere with binoculars. M3
contains about half a million stars, most of which are old and
red. The existence of young blue stars in M3 once posed a mystery,
but these blue stragglers are now thought to form via stellar interactions.