Starsglaxiesspace - SPACE

Subphylum Urochordata

Subphylum Urochordata (also called Tunicata) includes tunicates, salps, and larvaceans. This subphylum, along with subphylum Cephalochordata, is informally classified under protochordates. Protochordates are “primitive” chordates that are not vertebrates. Most adult tunicates are sessile and do not show chordate characteristics. However tunicates have a free-swimming larval stage that exhibits all chordate characteristics. Tunicates get their name from the outer covering, called a tunic, which cloaks their body.

The first two photos show pictures of tunicate larva. The next three photos show pictures of adult tunicates.

“More Giant Galaxies Discovered in the Early Universe”

 Astronomers using the Atacama Large Millimeter/millimeter Array (ALMA) in Chile have discovered two giant galaxies that existed when the universe was only 780 million years old, or about 5 percent of its current age. These two galaxies, known collectively as SPTO311-58, appear to be within an even-more-massive dark matter halo, containing several trillion times the mass of our sun.  This discovery is quite surprising for scientists. Like how suns and planets are formed from clumps of gas and rock sticking together, astronomers expected the first galaxies to resemble little dwarf galaxies such as those seen today. Yet, nature has surprised everybody, revealing examples of massive galaxies - even for today’s standards.  The researchers wrote the following statement: “This ‘de-lensing’ process provided intriguing details about the galaxies, showing that the larger of the two is forming stars at a rate of 2,900 solar masses per year. It also contains about 270 billion times the mass of our sun in gas and nearly 3 billion times the mass of our sun in dust.” This shows that these galaxies very likely merged to eventually form the largest galaxy ever observed at that time period in cosmic history.

Read more about this fascinating story at: http://earthsky.org/space/primordial-galaxies-spt0311-58-dark-matter-early-universe

Images: Artist’s concept via NRAO/ AUI/ NSF; D. Berry. & Composite Image via ALMA (ESO/NAOJ/NRAO), Marrone, et al.; B. Saxton (NRAO/AUI/NSF); NASA/ESA Hubble.

It’s just… Beautiful! Isn’t it?

Herbig-Haro 666 (HH 666)

A NEW APPROACH FOR DETECTING PLANETS IN THE ALPHA CENTAURI SYSTEM

Yale astronomers have taken a fresh look at the nearby Alpha Centauri star system and found new ways to narrow the search for habitable planets there.

According to a study led by Professor Debra Fischer and graduate student Lily Zhao, there may be small, Earth-like planets in Alpha Centauri that have been overlooked. Meanwhile, the study ruled out the existence of a number of larger planets in the system that had popped up in previous models.

“The universe has told us the most common types of planets are small planets, and our study shows these are exactly the ones that are most likely to be orbiting Alpha Centauri A and B,” said Fischer, a leading expert on exoplanets who has devoted decades of research to the search for an Earth analog.

The new study appears in the Astronomical Journal. Co-authors are John Brewer and Matt Giguere of Yale and Bárbara Rojas-Ayala of Universidad Andrés Bello in Chile.

The Alpha Centauri system is located 1.3 parsecs (24.9 trillion miles) from Earth, making it our closest neighboring system. It has three stars: Centauri A, Centauri B, and Proxima Centauri. Last year, the discovery of an Earth-like planet orbiting Proxima Centauri set off a new wave of scientific and public interest in the system.

“Because Alpha Centauri is so close, it is our first stop outside our solar system,” Fischer said. “There’s almost certain to be small, rocky planets around Alpha Centauri A and B.”

The findings are based on data coming in from a new wave of more advanced spectrographic instruments at observatories located in Chile: CHIRON, a spectrograph built by Fischer’s team; HARPS, built by a team from Geneva; and UVES, part of the Very Large Telescope Array. “The precision of our instruments hasn’t been good enough, until now,” Fischer said.

The researchers set up a grid system for the Alpha Centauri system and asked, based on the spectrographic analysis, “If there was a small, rocky planet in the habitable zone, would we have been able to detect it?” Often, the answer came back: “No.”

Zhao, the study’s first author, determined that for Alpha Centauri A, there might still be orbiting planets that are smaller than 50 Earth masses. For Alpha Centauri B there might be orbiting planets than are smaller than 8 Earth masses; for Proxima Centauri, there might be orbiting planets that are less than one-half of Earth’s mass.

In addition, the study eliminated the possibility of a number of larger planets. Zhao said this takes away the possibility of Jupiter-sized planets causing asteroids that might hit or change the orbits of smaller, Earth-like planets.

“This is a very green study in that it recycles existing data to draw new conclusions,” said Zhao. “By using the data in a different way, we are able to rule out large planets that could endanger small, habitable worlds and narrow down the search area for future investigations.”

This new information will help astronomers prioritize their efforts to detect additional planets in the system, the researchers said. Likewise, the continuing effort by Fischer and others to improve spectrographic technology will help identify and understand the composition of exoplanets.

Illustration by Michael S. Helfenbein