NASA Scientist Finds World With Triple Sunsets

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov

Whitney Clavin (818) 354-4673
Jet Propulsion Laboratory, Pasadena, Calif.

News Release: 2005-115 July 13, 2005

NASA Scientist Finds World With Triple Sunsets

A NASA-funded astronomer has discovered a world where
the sun sets over the horizon, followed by a second sun
and then a third. The new planet, called HD 188753 Ab,
is the first known to reside in a classic triple-star
system.

"The sky view from this planet would be spectacular,
with an occasional triple sunset," said Dr. Maciej
Konacki (MATCH-ee Konn-ATZ-kee) of the California
Institute of Technology, Pasadena, Calif., who found
the planet using the Keck I telescope atop Mauna Kea
mountain in Hawaii. "Before now, we had no clues about
whether planets could form in such gravitationally
complex systems."

The finding, reported in this week's issue of Nature,
suggests that planets are more robust than previously
believed.

"This is good news for planets," said Dr. Shri Kulkarni,
who oversees Konacki's research at Caltech. "Planets may
live in all sorts of interesting neighborhoods that,
until now, have gone largely unexplored." Kulkarni is the
interdisciplinary scientist for NASA's planned SIM
PlanetQuest mission, which will search for signs of
Earth-like worlds.

Systems with multiple stars are widespread throughout
the universe, accounting for more than half of all stars.
Our Sun's closest star, Alpha Centauri, is a member of a
trio.

"Multiple-star systems have not been popular planet-hunting
grounds," said Konacki. "They are difficult to observe and
were believed to be inhospitable to planets."

The new planet belongs to a common class of extrasolar
planets called "hot Jupiters," which are gas giants that zip
closely around their parent stars. In this case, the planet
whips every 3.3 days around a star that is circled every 25.7
years by a pirouetting pair of stars locked in a 156-day orbit.

The circus-like trio of stars is a cramped bunch, fitting
into the same amount of space as the distance between Saturn
and our Sun. Such tight living quarters throw theories of hot
Jupiter formation into question. Astronomers had thought that
hot Jupiters formed far away from their parent stars, before
migrating inward.

"In this close-knit system, there would be no room at the
outskirts of the parent star system for a planet to grow," said
Konacki.

Previously, astronomers had identified planets around about
20 binary stars and one set of triple stars. But the stars in
those systems had a lot of space between them. Most
multiple-star arrangements are crowded together and difficult to
study.

Konacki overcame this challenge using a modified version of the
radial velocity, or "wobble," planet-hunting technique. In the
traditional wobble method, a planet's presence is inferred by
the gravitational tug, or wobble, it induces in its parent star.
The strategy works well for single stars or far-apart binary
and triple stars, but could not be applied to close-star
systems because the stars' light blends together.

By developing detailed models of close-star systems, Konacki
was able to tease apart the tangled starlight. This allowed
him to pinpoint, for the first time, the tug of a planet on a
star snuggled next to other stars. Of 20 systems examined so
far, HD 188753, located 149 light-years away, was the only
one found to harbor a planet.

Hot Jupiters are believed to form out of thick disks, or
"doughnuts," of material that swirl around the outer fringes
of young stars. The disk material clumps together to form a
solid core, then pulls gas onto it. Eventually, the gas giant
drifts inward. The discovery of a world under three suns
contradicts this scenario. HD 188753 would have sported a
truncated disk in its youth, due to the disruptive presence of
its stellar companions. That leaves no room for HD 188753's
planet to form, and raises a host of new questions.

The masses of the three stars in HD 188753 system range from
two-thirds to about the same mass as our Sun. The planet is
slightly more massive than Jupiter.

For artist's concepts and other graphics, visit

http://planetquest.jpl.nasa.gov/ .

For information about NASA and agency programs on the Web,
visit

http://www.nasa.gov/home/index.html .

-end-

Imagine, we now know that a planet can have three suns.

Maybe the center of mass of the three remains constant, and the planet
revolves around that. Seasons would be chaotic as hell. Winter could come
after Summer, and then after Spring.

I guess the planet would have to circle hot stars to have a chance at life,
otherwise it could not be far away enough to avoid the great temperature
changes.

But even red giants are hot if they are big enough.

So you could get up to a red, then a blue, and then a green star.

Literary artists will have to find their way there soon.



wrote in message
ups.com...
MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov

Whitney Clavin (818) 354-4673
Jet Propulsion Laboratory, Pasadena, Calif.

News Release: 2005-115 July 13, 2005

NASA Scientist Finds World With Triple Sunsets

A NASA-funded astronomer has discovered a world where
the sun sets over the horizon, followed by a second sun
and then a third. The new planet, called HD 188753 Ab,
is the first known to reside in a classic triple-star
system.

"The sky view from this planet would be spectacular,
with an occasional triple sunset," said Dr. Maciej
Konacki (MATCH-ee Konn-ATZ-kee) of the California
Institute of Technology, Pasadena, Calif., who found
the planet using the Keck I telescope atop Mauna Kea
mountain in Hawaii. "Before now, we had no clues about
whether planets could form in such gravitationally
complex systems."

The finding, reported in this week's issue of Nature,
suggests that planets are more robust than previously
believed.

Mark Earnest wrote:
Imagine, we now know that a planet can have three suns.

Maybe the center of mass of the three remains constant, and the planet
revolves around that. Seasons would be chaotic as hell. Winter could come
after Summer, and then after Spring.
AFAIK there are two ways this could work:
1) the planet circles very close around one of the stars
2) the planet circles very far away around all three stars

Lots of Greetings!
Volker

On Wed, 13 Jul 2005 19:24:28 -0500, "Mark Earnest"
etched in cyberspace:

Imagine, we now know that a planet can have three suns.

Maybe the center of mass of the three remains constant, and the planet
revolves around that. Seasons would be chaotic as hell. Winter could come
after Summer, and then after Spring.

I guess the planet would have to circle hot stars to have a chance at life,
otherwise it could not be far away enough to avoid the great temperature
changes.

But even red giants are hot if they are big enough.

So you could get up to a red, then a blue, and then a green star.

Literary artists will have to find their way there soon.

Sounds like that in this case that the planet does not orbit around
the three starts, but that the planet orbits one star, and the other
two stars orbit further out. The night would be seriously shortened
by having suns arranged around the sky. The temperature would be
dominated by the closest star.
X X
X
X X

"Octa Ex" wrote in message
...
On Wed, 13 Jul 2005 19:24:28 -0500, "Mark Earnest"
etched in cyberspace:

Imagine, we now know that a planet can have three suns.

Maybe the center of mass of the three remains constant, and the planet
revolves around that. Seasons would be chaotic as hell. Winter could
come
after Summer, and then after Spring.

I guess the planet would have to circle hot stars to have a chance at
life,
otherwise it could not be far away enough to avoid the great temperature
changes.

But even red giants are hot if they are big enough.

So you could get up to a red, then a blue, and then a green star.

Literary artists will have to find their way there soon.

Sounds like that in this case that the planet does not orbit around
the three starts, but that the planet orbits one star, and the other
two stars orbit further out. The night would be seriously shortened
by having suns arranged around the sky. The temperature would be
dominated by the closest star.

Cool. What if the three stars share the planet in a strange little dance,
where one captures it gravitationally, and then another one does, followed
by the third star?
The seasons would be a roller coaster, with possibly a different colored
star for each season.

"ME" == Mark Earnest writes:

A NASA-funded astronomer has discovered a world where the sun sets
over the horizon, followed by a second sun and then a third. The
new planet, called HD 188753 Ab, is the first known to reside in a
classic triple-star system.

"The sky view from this planet would be spectacular, with an
occasional triple sunset," said Dr. Maciej Konacki (...) of the
California Institute of Technology, Pasadena, Calif., who found the
planet using the Keck I telescope atop Mauna Kea mountain in
Hawaii. "Before now, we had no clues about whether planets could
form in such gravitationally complex systems."

ME Imagine, we now know that a planet can have three suns.

ME Maybe the center of mass of the three remains constant, and the
ME planet revolves around that. Seasons would be chaotic as hell.
ME Winter could come after Summer, and then after Spring.

ME I guess the planet would have to circle hot stars to have a chance
ME at life, otherwise it could not be far away enough to avoid the
ME great temperature changes.

The summary at Nature indicates that HD 188753 consists of a star (A)
orbited by a pair of stars (B and C). The planet orbits HD 188753 A.
The binary orbits HD 188753 at a distance of something like 10 AU (at
least the orbit of Saturn). The summary also says that HD 188753 is
similar to the Sun, although SIMBAD lists it as a K0 star, which would
be somewhat cooler than the Sun. Moreover, SIMBAD indicates that it
is a spectroscopic binary meaning that the other stars in the system
are not resolved.

This indicates to me that HD 188753 B and C are likely to be K or M
class stars. Consequently, I think that the triple sunsets would not
be all that spectacular. In fact, it seems like the Alpha Centauri
system might be more spectacular (were it known to contain a planet).
There have been previous posts on this newsgroup about how Alpha
Centauri B appears from a planet orbiting Alpha Centauri A. Alpha
Centauri B would clearly be noticable but it would not affect the
climate of a hypothetical Earth-like planet around Alpha Centauri A.

There almost certainly would not be anything like the sunsets on
Tatooine.

--
Lt. Lazio, HTML police | e-mail:
No means no, stop rape. | http://patriot.net/%7Ejlazio/
sci.astro FAQ at http://sciastro.astronomy.net/sci.astro.html

"Joseph Lazio" wrote in message
...
"ME" == Mark Earnest writes:

A NASA-funded astronomer has discovered a world where the sun sets
over the horizon, followed by a second sun and then a third. The
new planet, called HD 188753 Ab, is the first known to reside in a
classic triple-star system.

"The sky view from this planet would be spectacular, with an
occasional triple sunset," said Dr. Maciej Konacki (...) of the
California Institute of Technology, Pasadena, Calif., who found the
planet using the Keck I telescope atop Mauna Kea mountain in
Hawaii. "Before now, we had no clues about whether planets could
form in such gravitationally complex systems."

ME Imagine, we now know that a planet can have three suns.

ME Maybe the center of mass of the three remains constant, and the
ME planet revolves around that. Seasons would be chaotic as hell.
ME Winter could come after Summer, and then after Spring.

ME I guess the planet would have to circle hot stars to have a chance
ME at life, otherwise it could not be far away enough to avoid the
ME great temperature changes.

The summary at Nature indicates that HD 188753 consists of a star (A)
orbited by a pair of stars (B and C). The planet orbits HD 188753 A.
The binary orbits HD 188753 at a distance of something like 10 AU (at
least the orbit of Saturn). The summary also says that HD 188753 is
similar to the Sun, although SIMBAD lists it as a K0 star, which would
be somewhat cooler than the Sun. Moreover, SIMBAD indicates that it
is a spectroscopic binary meaning that the other stars in the system
are not resolved.

This indicates to me that HD 188753 B and C are likely to be K or M
class stars. Consequently, I think that the triple sunsets would not
be all that spectacular. In fact, it seems like the Alpha Centauri
system might be more spectacular (were it known to contain a planet).
There have been previous posts on this newsgroup about how Alpha
Centauri B appears from a planet orbiting Alpha Centauri A. Alpha
Centauri B would clearly be noticable but it would not affect the
climate of a hypothetical Earth-like planet around Alpha Centauri A.

There almost certainly would not be anything like the sunsets on
Tatooine.

Didn't you see the NASA portrait of the triple sunset?:

http://planetquest.jpl.nasa.gov/