Latest Happening In Space

Exoplanet Phases Seen in Optical Light :-

For the first time, astronomers have observed the phases of an extrasolar planet in visible light, as the world orbits around its star.


The planet, CoRoT-1b, was the first planet discovered by the French CoRoT (Convection Rotation and Planetary Transit) satellite about 2.5 years ago. It is about 1,600 light years away in the constellation Monoceros.>


CoRoT-1b is a so-called "hot Jupiter." These planets are the size of Jupiter but orbit very closely to their stars (CoRoT-1b orbits its star in just 36 hours). Hot Jupiters are expected to be tidally locked, with one side always facing their stars, the other permanently dark (our own moon is tidally locked with the Earth, only showing its "near side" to us).


If these planets do have permanent daysides and nightsides, astronomers expect to see very large temperatures differences between the two hemispheres, depending on which one was in view from Earth's vantage point.


Astronomers had taken infrared measurements of these light and dark phases, but the CoRoT-1b measurements mark the first time they have been seen in the optical wavelengths, and they show that the nightside of the planet is completely dark, while the dayside is strongly heated by the star up to about 3,600 degrees Fahrenheit (2,000 degrees Celsius).


"So we see a very large difference between the dayside and the nightside," said study author Ignas Snellen of Leiden University in the Netherlands.


The measured effect is very much like the changing phases of objects in our own solar system, such as Earth's moon, when the sun shines on the moon from different directions while the moon revolves around the Earth. Although in the case of our moon this is reflected sun-light, while for CoRoT-1b it is probably heat radiation.


The observations, detailed in the May 28 issue of the journal Nature, also shed light on the atmosphere of the exoplanet and suggest that there is not a lot of transfer of heat from the dayside to the nightside of the planet. Another observed exoplanet had less of a heat difference between its two sides, suggesting that wind was transporting the incoming solar energy, but "for this planet, that is apparently not the case," Snellen told SPACE.com.


Instead, CoRoT-1b may have certain molecules in its atmosphere that absorb and re-radiate the light coming from the star on the dayside before that energy can be transferred to the other side of the planet.


Optical observations can also tell astronomers whether or not any of the light they are seeing is reflected starlight, which would suggest the exoplanet had clouds. Unfortunately, the researchers could not tell if any of the light from CoRoT-1b was reflected, Snellen said.


To determine whether or not the light is reflected, the astronomers will need observations of the planet at multiple wavelengths, Snellen said.


Snellen and his colleagues have already started to look at observations of other exoplanets to glean more information on the phases and atmospheres of hot Jupiters


Close-up Look at Black Hole Reveals Feeding Frenzy:-

Astronomers are getting a close-up look at a cosmic eating machine: a spinning black hole that devours the mass equivalent of two Earths per hour, verging on the limit of its feeding ability.

Supermassive black holes can weigh as much as a billion suns or more and are thought to reside at the centers of most, if not all, large galaxies. Their gravity is so powerful it traps even light, making black holes invisible. Their presence is inferred by watching the motions of stars and gas around them, along with the radiation that's generated in their frenzied vicinities.

The behemoth of interest in the new close-up study, which will be published in the May 28 issue of the journal Nature, lies at the center of a distant active galaxy known as 1H0707-495. Using data from the European Space Agency's XMM-Newton observatory, astronomers analyzed X-rays emitted during the black hole's feeding frenzy.

As matter swirls in toward a black hole, gravity makes it travel at significant fractions of light-speed. That generates X-rays and other radiation that can give astronomers information about the spin of the black hole and its size, among other details.

In this case, the astronomers say they are tracking matter that's within twice the radius of the black hole itself.

Specifically, the XMM-Newton detections suggested the galaxy's core is much richer in iron than the rest of the galaxy. In addition, there was a time lag of 30 seconds between changes in the X-ray light observed directly and those seen in its reflection from the disk. From this delay, the astronomers estimate the black hole weighs about 3 million to 5 million solar masses – modest by supermassive black hole standards.

The team will continue to track the galaxy and map out the accreting process of this supermassive black hole. Far from being a steady process, like muddy water slipping down a plughole, a feeding black hole is a messy eater.

"Accretion is a very messy process because of the magnetic fields that are involved," said study scientist Andrew Fabian of the University of Cambridge.

Hidden Radio Supernova Finally Found :-

An elusive supernova explosion, detectable only in radio wavelengths, was discovered last month in the nearby galaxy M82.


The object, dubbed SN 2008iz, is the closest supernova discovered by scientists in the past five years. It would have been visible even to amateur telescopes, were it not for the dense gas and dust surrounding the exploding star, which left it invisible in every part of the spectrum except the radio wavelengths.


The supernova's home galaxy, M82, is an irregular galaxy in a nearby galaxy group located 12 million light-years from Earth.


Despite being smaller than the Milky Way, it harbors a vigorous central starburst in the inner few hundred light-years. In this stellar factory more stars are presently born than in the entire Milky Way.


M82 is often called an "exploding galaxy," because it looks as if being torn apart in optical and infrared images as the result of numerous supernova explosions from massive stars. Many remnants from previous supernovas are seen in radio images of M82, and a new supernova explosion was long overdue.


Astronomers have been waiting to catch the next big blast for more than 25 years and had started to wonder why the galaxy has been so silent in recent years. In the end, it took a little digging and looking in the right wavelengths.


The new discovery was first made when Andreas Brunthaler of the Max-Planck-Institut fur Radioastronomie in Bonn, Germany, examined data from April 8 with the Very Large Array (VLA) of the National Radio Astronomy Observatory, an interferometer of 27 identical 25-meter telescopes in New Mexico.


"I then looked back into older data we had from March and May last year, and there it was as well, outshining the entire galaxy!" Brunthaler said.


Radio emission can be detected only from core collapse supernovas, where the core of a massive star collapses and produces a black hole or a neutron star. It is produced when the shock wave of the explosion propagates into dense material surrounding the star, usually material that was shed from the massive progenitor star before it exploded.


But observations of M82 taken last year with optical telescopes to search for new supernovas showed no signs of this explosion. The supernova is also hidden on ultraviolet and X-ray images.


The supernova exploded close to the center of the galaxy in a very dense interstellar environment, which could explain why M82 has been silent for so long: many of these events may actually be something like "underground explosions," where the bright flash of light is covered under huge clouds of gas and dust and only radio waves can penetrate this dense material.


"This cosmic catastrophe shows that using our radio telescopes we have a front-row seat to observe the otherwise hidden universe," said Heino Falcke of the University of Nijmegen/ASTRON.


By combining data from the 10 telescopes of the Very Long Baseline Array (VLBA), the VLA, the Green Bank Telescope in the USA, and the Effelsberg 100-meter telescope in Germany, using the technique of Very Long Baseline Interferometry (VLBI), the team was able to produce images that show a ring-like structure expanding at more than 40 million km/h or 4 percent of the speed of light, typical for supernovae.


The team estimates that the supernova exploded in late January or early February 2008. Only three months after the explosion, the ring was already 650 times larger than Earth's orbit around the sun.