Credit & Copyright: Pierre Kervella
(Observatoire de Paris),
et al.,
ESO
Explanation:
This dusty reflection nebula surrounds pulsating
star RS Pup, some 10 times more massive than the Sun and
on average 15,000 times more luminous.
In fact, RS Pup is a
Cepheid type
variable star; a class of stars whose
brightness
is used to estimate distances to nearby galaxies
as one of the first steps in establishing the
cosmic
distance scale.
As RS Pup pulsates
over a period of about 40 days, its
regular changes in brightness are also seen along the
nebula delayed in time,
effectively a a light echo.
The otherwise overwhelming light from RS Pup itself is
hidden behind the dark central stripe in the color image.
Using
new measurements of the time delay and
angular size of the nebula, the known
speed of light allows astronomers to geometrically
determine the distance to RS Pup to be
6,500 light-years, with a remarkably small error of
plus or minus 90 light-years.
An impressive achievement for stellar astronomy, the
echo-measured distance also more accurately establishes the
true brightness of RS Pup,
and by extension other Cepheid stars, improving
the knowledge
of
distances to
galaxies beyond
the Milky Way.
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 |
Январь Февраль Март Апрель Май Июнь Июль Август Сентябрь Октябрь Ноябрь Декабрь |
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
|
Публикации с ключевыми словами:
cepheid - distance scale - light echo - Цефеиды - шкала расстояний
Публикации со словами: cepheid - distance scale - light echo - Цефеиды - шкала расстояний | |
См. также:
Все публикации на ту же тему >> | |
