The very small number of BLAPs known so
far points to a rare, unexplored episode in
stellar evolution. This work is published in
the journal Nature Astronomy, and is avail-
able online (subscription required). The ar-
ticle is also on astro-ph.
The Little Star That Could …
Survive a Supernova Explosion
Astronomers have identified a white dwarf
star in our solar neighborhood moving fast-
er than the escape velocity of the Milky Way.
The internation al team, led by Stephane
Vennes (Astronomical Institute in the Czech
Republic), used telescopes in Arizona and
the Canary Islands, as well as the GRACES
(Gemini Remote Access to CFHT ESPaDOnS)
spectrograph atop Maunakea to study this
celestial speedster, which is thought to have
been expelled like shrapnel from a peculiar
Type Ia supernova explosion some 50 mil-
lion years ago.
The speedy white dwarf, known as LP40-365,
was first identified with the National Science
Foundation’s (NSF) Mayall 4-meter telescope
at Kitt Peak National Observatory in Arizona.
Over the next two years, the discovery team
received critical follow-up observations from
the Canary Islands and Maunakea, which
they analyzed using state-of-the-art com-
puter codes. The analysis proved the star’s
compact nature and exotic chemical com-
position, as well as its extraordinary Galactic
trajectory, which puts it on a path out of the
Milky Way with no return.
Astronomers once thought that nothing sur-
vives a Type Ia supernova, which occurs in a
binary system that includes a white dwarf.
However, a new class of models called “Sub-
luminous type Ia Supernova” (also known as
type Iax) can leave a partially burned rem-
nant that is instantly ejected at high velocity.
LP40-365 is the first observational evidence
that such high-velocity remnants of failed
October 2017
Type Ia supernovae actually exist in our Gal-
axy, and therefore it is an invaluable object
to improve our understanding of these cos-
mological standard candles.
Many more of these objects may be lurking
in the Milky Way and awaiting discovery. The
recent European Space Agency’s Gaia mis-
sion may well help us discover many more of
these objects and help us understand how
a little white dwarf star can survive a super-
nova explosion.
This research is published in the August 18,
2017, issue of Science.
Gemini North Unmasks the
Infrared Quintuplet
The “Infrared Quintuplet” has long been a
mystery to astronomers. These five infrared-
luminous stars lie at the center of hundreds
of hot and massive stars (collectively known
as the Quintuplet Cluster) only 30 parsecs
from the central supermassive black hole at
the core of our Galaxy. Most objects in the
center of the Milky Way are highly obscured
from our view by intervening dust at visible
wavelengths. The stars in the Infrared Quin-
tuplet, however, are further obscured by
their own dust shells. These warm, cocoon-
like shells emit bright infrared continuum ra-
diation, diluting any infrared light from the
stars themselves. The combination of these
effects has made it very challenging, if not
impossible, at any infrared wavelength to
detect light from the interiors of the shells
… or so it was thought.
As reported in the August 18, 2017, edition
of The Astrophysical Journal, Gemini astron-
omer Tom Geballe and his team used the
Gemini Near-InfraRed Spectrometer (GNIRS)
and Near-infrared Integral Field Spectrom-
eter (NIFS) on the Gemini North telescope to
penetrate the dusty cocoons of the Infrared
Quintuplet and gather data on its members
(Figure 2).
GeminiFocus
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