Hunting for signs of extrasolar planets — or exoplanets — is hard, but counting them can also prove tricky. Today, however, our historic era of exoplanetary discovery has turned into a red letter day; the first 1,000 exoplanets to be confirmed have been added to the Europe-based Extrasolar Planets Encyclopaedia.
For the last few weeks, astronomers (and the science media) have been waiting with bated breath as the confirmed exoplanet count tallied closer and closer to the 1,000 mark. Then, with the help of the Super Wide Angle Search for Planets (SuperWASP) collaboration, the number jumped from 999 to 1,010 overnight.
The 11 new additions may be noteworthy as breaking the 1,000 barrier, but they’re certainly not noteworthy as being anything remotely habitable. All 11 scoot around their parent stars with periods of between 8 and less than 2 days — making all of these new confirmed worlds “hot-Jupiters.”
Keeping a tally of exoplanets isn’t as easy as it seems. Although the Extrasolar Planets Encyclopaedia has been updated, it may be some time until other exoplanetary lists are updated. For example, NASA’s Jet Propulsion Laboratory keeps its own record called the Exoplanet Archive which currently lists the tally at 919. Why the discrepancy? One reason, according to New Scientist, is that the Extrasolar Planets Encyclopaedia lists exoplanets as soon as their confirmation is announced at conferences. The NASA list, however, only lists them once they’ve been published in a scientific journal. The NASA list will therefore always lag its European counterpart.
Also, some of the 1,000 exoplanets in the list are subject to intense scrutiny as there are some very massive worlds with stellar characteristics. After further study, some may be characterized as brown dwarfs, or “failed stars,” bumping them from being true planetary bodies.
1,000 exoplanets may seem like a big number, but the now defunct NASA Kepler Space Telescope suggests that there are thousands of candidate exoplanetary signals in its transit data awaiting confirmation by other surveys. But even if we end up confirming thousands more over the coming years, that number will pale into insignificance considering there are an estimated 100 billion alien worlds orbiting other stars in our galaxy. Our quest to find habitable exoplanets has only just begun.
But for now, welcome the newest 11 confirmed exoplanets:
WASP-76 b — 0.92 Jupiter masses, orbital period: 1.8 days
WASP-82 b — 1.24 Jupiters, 2.7 days
WASP-84 b — 0.694 Jupiters, 8.5 days
WASP-90 b — 0.63 Jupiters, 3.9 days
WASP-95 b — 1.13 Jupiters, 2.2 days
WASP-96 b — 0.48 Jupiters, 3.4 days
WASP-97 b — 1.32 Jupiters, 2.1 days
WASP-98 b — 0.83 Jupiters, 3 days
WASP-99 b — 2.78 Jupiters, 5.8 days
WASP-100 b — 2.03 Jupiters, 2.8 days
WASP-101 b — 0.5 Jupiters, 3.6 days
Image credit: ESO