Protoplanetary Disk Could Reveal Planetary Abortion

TW Hydrae is a young star sporting a beautiful protoplanetary disk that is almost perfectly face-on from our perspective. Within that disk, dark tracks have captivated astronomers who believe they hold clues to the earliest stages of planetary formation. In short, TW Hydrae is a stellar "petri dish," only 175 light-years away, showing us exactly where baby planets come from.

This now-famous observation, captured by the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, has gone one step further. In March, astronomers studying the emissions from the protoplanetary dust spotted something potentially groundbreaking. Close to the 10 million year-old star was a region lacking dust, possibly evidence for a world being born at roughly the same distance from the star as Earth orbits the sun. Could this be the earliest stages of the birth of an Earth-like planet? If so, the implications would be profound.

However, after carrying out computer simulations of the TW Hydrae protoplanetary disk, an international team of researchers led by Barbara Ercolano of Ludwig-Maximilians-Universität München, Germany, believes there may be another explanation for this innermost empty region and, sadly, it doesn't include a baby "Earth 2.0." In fact, the star may have aborted its birth.

When stars are young, they pump out huge amounts of ionizing radiation and blast out powerful stellar winds, vaporizing any dust that strays too close and blowing away any gases. In the case of a planet-forming disk around a young star, this could mean a region close to the star would be burnt away, leaving a gap.

ALMA observation of the TW Hydrae planet-forming disk, including the suspected Earth-like planet formation region that may, actually, be a region of photoevaporation.

The process, called "photoevaporation," could be ongoing in the TW Hydrae system, directly impacting the innermost region of the disk. The outer rings in the disk, however, are still likely being formed by accreting exoplanets sweeping up material as they orbit, it's just the inner region that is being vaporized.

Although this is obviously bad news for seeing the birth of an Earth-like exoplanent, TW Hydrae is proving an unprecedented opportunity for astronomers to study the destructive nature of a star in its earliest stages of evolution.

From Discovery News