BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:Rapid Rotation of a Cold Extremely Metal-poor Brown Dwarf
DTSTART;VALUE=DATE-TIME:20261028T181700Z
DTEND;VALUE=DATE-TIME:20261028T181800Z
DTSTAMP;VALUE=DATE-TIME:20261028T201804Z
UID:indico-contribution-3708@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Jerry J.-Y. Zhang (Western University)\nWe report th
 e first detection of brightness variability in an extremely metal-poor bro
 wn dwarf. These objects are ancient\, very low-mass members of the Milky W
 ay that formed when the Galaxy contained far fewer heavy elements than it 
 does today. Using the 10.4-m Gran Telescopio Canarias\, we found that the 
 nearest known extreme T subdwarf\, WISEA\,J181006.1$-$101000.5\, changes i
 ts $J$-band brightness by $1.14\\pm0.26%$ every $73.7\\pm1.5$ minutes. We 
 interpret this periodic signal as the rotation of an uneven atmosphere int
 o and out of view. The object completes a rotation about 8 times faster th
 an Jupiter\, similar to watching changing cloud patterns on a rapidly rota
 ting Jupiter. An independent measurement of its projected rotational veloc
 ity\, $v\\sin i = 125^{+25}_{-23}\\ {\\rm km\,s^{-1}}$\, confirms that the
  object is an extremely fast rotator. Such rapid rotation may be a natural
  consequence of its old age and compact size: unlike stars\, these ultraco
 ol objects have no efficient mechanism to slow their rotation over billion
 s of years. This first detection opens a new window into the atmospheres a
 nd rotation of the oldest ultracool objects in the Galaxy.\n\nhttps://nyx.
 physics.mcgill.ca/event/587/contributions/3708/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3708/
END:VEVENT
END:VCALENDAR