ESO telescope images planet around most massive star pair to date

Date:
December 8, 2021
Source:
ESO
Summary:
The European Southern Observatory's Very Large Telescope (ESO's
VLT) has captured an image of a planet orbiting b Centauri, a
two-star system that can be seen with the naked eye. This is the
hottest and most massive planet-hosting star system found to date,
and the planet was spotted orbiting it at 100 times the distance
Jupiter orbits the Sun. Some astronomers believed planets could
not exist around stars this massive and this hot -- until now.



FULL STORY ==========================================================================
The European Southern Observatory's Very Large Telescope (ESO's VLT)
has captured an image of a planet orbiting b Centauri, a two-star
system that can be seen with the naked eye. This is the hottest and
most massive planet-hosting star system found to date, and the planet
was spotted orbiting it at 100 times the distance Jupiter orbits the
Sun. Some astronomers believed planets could not exist around stars this massive and this hot -- until now.


========================================================================== "Finding a planet around b Centauri was very exciting since it completely changes the picture about massive stars as planet hosts," explains Markus Janson, an astronomer at Stockholm University, Sweden and first author
of the new study published online today in Nature.

Located approximately 325 light-years away in the constellation Centaurus,
the b Centauri two-star system (also known as HIP 71865) has at least
six times the mass of the Sun, making it by far the most massive system
around which a planet has been confirmed. Until now, no planets had been spotted around a star more than three times as massive as the Sun.

Most massive stars are also very hot, and this system is no exception:
its main star is a so-called B-type star that is over three times as
hot as the Sun.

Owing to its intense temperature, it emits large amounts of ultraviolet
and X- ray radiation.

The large mass and the heat from this type of star have a strong impact
on the surrounding gas, that should work against planet formation. In particular, the hotter a star is, the more high-energy radiation
it produces, which causes the surrounding material to evaporate
faster. "B-type stars are generally considered as quite destructive and dangerous environments, so it was believed that it should be exceedingly difficult to form large planets around them," Janson says.

But the new discovery shows planets can in fact form in such severe star systems. "The planet in b Centauri is an alien world in an environment
that is completely different from what we experience here on Earth and in
our Solar System," explains co-author Gayathri Viswanath, a PhD student
at Stockholm University. "It's a harsh environment, dominated by extreme radiation, where everything is on a gigantic scale: the stars are bigger,
the planet is bigger, the distances are bigger." Indeed, the planet discovered, named b Centauri (AB)b or b Centauri b, is also extreme. It
is 10 times as massive as Jupiter, making it one of the most massive
planets ever found. Moreover, it moves around the star system in one of
the widest orbits yet discovered, at a distance a staggering 100 times
greater than the distance of Jupiter from the Sun. This large distance
from the central pair of stars could be key to the planet's survival.

These results were made possible thanks to the sophisticated Spectro- Polarimetric High-contrast Exoplanet REsearch instrument (SPHERE)
mounted on ESO's VLT in Chile. SPHERE has successfully imaged several
planets orbiting stars other than the Sun before, including taking the
first ever-image of two planets orbiting a Sun-like star.

However, SPHERE was not the first instrument to image this planet. As
part of their study, the team looked into archival data on the b Centauri system and discovered that the planet had actually been imaged more than
20 years ago by the ESO 3.6-m telescope, though it was not recognised
as a planet at the time.

With ESO's Extremely Large Telescope (ELT), due to start observations
later this decade, and with upgrades to the VLT, astronomers may be able
to unveil more about this planet's formation and features. "It will
be an intriguing task to try to figure out how it might have formed,
which is a mystery at the moment," concludes Janson.

========================================================================== Story Source: Materials provided by ESO. Note: Content may be edited
for style and length.


========================================================================== Related Multimedia:
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Planet_orbiting_b_Centauri,_a_two-star_system_that_can_be_seen_with_the
naked_eye ========================================================================== Journal Reference:
1. Markus Janson, Raffaele Gratton, Laetitia Rodet, Arthur Vigan,
Mickae"l
Bonnefoy, Philippe Delorme, Eric E. Mamajek, Sabine Reffert, Lukas
Stock, Gabriel-Dominique Marleau, Maud Langlois, Gae"l Chauvin,
Silvano Desidera, Simon Ringqvist, Lucio Mayer, Gayathri Viswanath,
Vito Squicciarini, Michael R. Meyer, Matthias Samland, Simon
Petrus, Ravit Helled, Matthew A. Kenworthy, Sascha P. Quanz,
Beth Biller, Thomas Henning, Dino Mesa, Natalia Engler,
Joseph C. Carson. A wide-orbit giant planet in the high-mass
b Centauri binary system. Nature, 2021; 600 (7888): 231 DOI:
10.1038/s41586-021-04124-8 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/12/211208123407.htm

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