Objects in the Hydra by wuyunyi


									          Objects in the Hydra

                       TWA 5B:
      X-rays Found From a Lightweight Brown Dwarf

                     M101 - Quasisoft Sources
Enigmatic X-ray Sources Point to Possible New Black Hole Population
                   RDCS 1252.9-2927:
                 A Distant Galaxy Cluster

X-rays Reveal Nature of Spiral Galaxy's Boisterous Activity
        SDSS 0836+0054, 1030+0524, & 1306+0356:
Chandra Finds Well-Established Black Holes In Distant Quasars
Flickering Quasar Helps Chandra Measure the Expansion Rate of the

                             Hydra A

                   Points of Interest in Hydra
                                Object      Name         Type/Translation
                                   1         M48          Open Star Cluster 5.5
                                                            Globular Star
                                   2         M68                               7.8
                                   3        M83             Spiral Galaxy      7.6
                                   4       Alphard       "Heart of the Hydra" 1.98

                                         Al Minliar al
                                   5                              *          4.44
                               M48       Galactic Cluster in Hydra
                               Common Names: None
                               NGC Number: 2548
                               Visual Magnitude: 5.5
                               ra: 8h 13.8m
                               dec: -4° 48'

Located in the constellation of Hydra, M48 is an open cluster of about 80 stars. 50 of these are
brighter than magnitude 13 and are easily visible in binoculars and small telescopes. The cluster
is easily visible to the naked eye under ideal observing conditions. M48 is about 23 light-years in
diameter and is located some 1,500 light-years from Earth. Its age is estimated at about 300
million years.

                               M68       Globular Cluster in Hydra
                               Common Names: None
                               NGC Number: 4590
                               Visual Magnitude: 7.8
                               ra: 12h 39.5m
                               dec: -26° 45'

The constellation Hydra contains a globular cluster of stars known as M68. This cluster is around
140 light-years in diameter and is located about 40,000 light-years from Earth. This is a relatively
small cluster that may be difficult to locate with binoculars. It is an easy target for any telescope 4-
inches or larger.

                               M83       Galaxy in Hydra
                               Common Names: Southern Pinwheel
                               NGC Number: 5236
                               Visual Magnitude: 7.6
                               ra: 13h 37m
                               dec: -29° 52'

In the constellation Hydra can be found a spectacular face-on spiral galaxy. This is M83, the
Southern Pinwheel Galaxy. It earned its name from the distinct pinwheel shape of its long spiral
arms. Color photographs of this galaxy reveal a wide range of colors from the yellow central core
of old stars to the blue spiral arms of young stars. Several red knots can also be seen. These are
gaseous nebulae where active star formation is taking place. Dark lanes of dust are also visible
throughout the galaxy's disk. M83 is situated about 15 million light-years from Earth. It is receding
from us at around 337 km/sec. This galaxy has been the site of six supernovae, which is more
than any other Messier galaxy. It was also the first galaxy to be discovered beyond the local
ALPHARD (Alpha Hydrae). Not well known, but surprisingly prominent, Alphard
dominates the dim constellation Hydra, the Water Serpent, and is hence also known as
Alpha Hydrae. The star, right in the middle of the range of second magnitude (1.98), is
made more noticeable by lying within a fairly blank region of sky to the southwest of
brighter Regulus. Appropriately, its Arabic name means "the solitary one." A dark sky, or
better, binoculars, will show the star glowing a pale orange color, indicative of a giant
star, one of the most common kinds that inhabit the naked-eye sky. Its distance of 175
light years allows us to calculate a true luminosity that to the eye would be 400 times that
of the Sun. With a temperature of 4000 degrees Kelvin, the term "giant" is apt, as the star
is some 40 times larger than the Sun. Placed at the solar position, Alphard would extend
halfway to the orbit of Mercury. As such the star is in league with several others that
include both Arcturus and Aldebaran, which are more prominent because they are closer
to us even though Alphard is actually a bit more luminous (making it a so-called "bright
giant."). Alphard also distinguishes itself by being a mild form of "barium star," in which
barium and other elements that are formed by the slow capture of neutrons are enhanced.
Barium stars are thought to be doubles. When Alphard was young, it had a more massive
companion that died first, and in the process contaminated it with the by-products of
nuclear fusion that had been shovelled to the top. The companion has now died as a dim
white dwarf, and the star that had been contaminated is now itself dying, presenting us
with evidence for what once happened.

                                  lHydra the Watersnake.


Japanese search for aliens
Agen�e France-Presse                                                Wednesday, 2 March 2005

Two Japanese observatories have started looking for
signs of extraterrestrial life, one using a radio telescope,
the other an optical telescope.

"I don't think it would be any wonder if life like us exists
somewhere else as space is vast," says Mitsumi Fujishita,
radioastronomy professor at Kyushu Tokai University,
who heads the research.

There have been earlier Japanese efforts to detect signs of
aliens but this is the first such search involving a state-run
organisation, say the researchers.

The five-day search is being done jointly at the Nishi-
                                                                 Observatories in Japan are searching
Harima Astronomical Observatory and the state-run                for extraterrestrial life in the Hydra
Mizusawa Astrogeodynamics Observatory.                           constellation where a US researcher
                                                                 detected radio waves in the late
                                                                 1980s (Image: iStockphoto)
The Nishi-Harima observatory, with a 2 metre reflector
telescope, aims to detect light, while the Mizusawa observatory is using a radio telescope
with a diameter of 10 metres to try to find radio waves.

They will focus on the area near the Hydra constellation where a US researcher detected
radio waves in 1988.

Japan is drafting an ambitious space program, with a goal of a manned station on the
moon by 2025.

Last weekend it successfully launched a satellite into space, 15 months after a similar
unmanned launch failed disastrously.

                                                                         with ABC Science Online

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