Much to my kids’ chagrin, I enjoy leisurely wandering around The Home Depot (or any other tool/hardware store). Occasionally, I’ll find a new or improved tool that would help me finish a home improvement project. Likewise, astronomers continually discover new and improved tools to help them understand the cosmos better. Though it can’t be found in a “Galaxy Depot,” one particular new advance makes the search for extrasolar planets easier.
Astronomers have developed numerous techniques for finding planets outside the solar system. The direct detection method provides the most information about exoplanets—but major technical hurdles exist in trying to locate the small amount of light coming from the planet in the large bath of light produced by the planet’s star. Yet astronomers continue to make progress in overcoming these obstacles.
The most recent advance (highlighted in this Science Daily article) allows telescopes to detect planets as closes as 5.2 astronomical units (AU, equal to the distance from the Sun to Earth). In order to locate light from the planet, a telescope must mask the light from the star. While scientists have developed instruments and software (called coronagraphs) to accomplish this, the processes necessary for finding exoplanets usually cause some of the light to show up in regions where astronomers expect the planets.
However, careful design allows the coronagraphs to “push” the extraneous light to specific regions of the image. For example, a team of astronomers developed one coronagraph where the background light spreads to one side of the image, so the other side can be used for planet hunting (see image below). Using this instrument, the team observed the star β Pictoris and found a planet more massive than Jupiter, orbiting at a distance 35 percent larger than the Jupiter-Sun separation.1
In terms of habitable planets, most of the interesting planet formation processes occur at distances less than 10 AU. For nearby stars, advances in telescope technology now allow astronomers to find planets within this interesting range. The light from these planets also contains information about the planetary atmospheres, which helps determine if a planet might show signs of life.
When planet hunters eventually find Earth-sized planets in the zone where liquid water could exist, they will have a tool to evaluate whether the commonly-held minimalist model of habitable planets is correct or not. Here at RTB, we fully expect that the habitability tests made possible by this and future advances in direct detection techniques will affirm that habitability requires far more than strictly naturalistic processes can produce. Truly habitable planets require the work of a supernatural Designer.
- Sascha P. Quanz et al., “First Results from Very Large Telescope Apodizing Phase Plate: 4 µm Images of the Exoplanet β Pictoris b,” Astrophysical Journal Letters 722 (October 10, 2010): L49–L53.