Featured Research

from universities, journals, and other organizations

Hubble Sees Bare Neutron Star Streaking Across Space

Date:
November 13, 2000
Source:
Space Telescope Science Institute
Summary:
It's as big as Manhattan Island, is 10 trillion times denser than steel and is hurtling our way at speeds over 100 times faster than a supersonic jet. An alien spaceship? No, it's a runaway neutron star, called RX J185635-3754, forged in a stellar explosion that would have been visible to our distant ancestors in 1 million B.C.

It's as big as Manhattan Island, is 10 trillion times denser than steel and is hurtling our way at speeds over 100 times faster than a supersonic jet. An alien spaceship? No, it's a runaway neutron star, called RX J185635-3754, forged in a stellar explosion that would have been visible to our distant ancestors in 1 million B.C.

Related Articles


Precise observations made with NASA's Hubble telescope confirm that the interstellar interloper turns out to be the closest neutron star ever seen. Now located 200 light-years away in the southern constellation Corona Australis, it will swing by Earth at a safe distance of 170 light-years in about 300,000 years. A light-year is the distance traveled by light in a full year (about 6 trillion miles).

Because it is the closest neutron star ever seen and its distance has been well established by Hubble, astronomers can compare stellar theories against a variety of its physical properties such as size, inherent brightness, and true age.

Since the object has no companion star that would affect its appearance, this discovery will allow future astronomers to more easily confirm stellar theories. The results are being presented today at the 2000 meeting of the American Astronomical Society's High Energy Astrophysics Division (HEAD) in Honolulu, HI.

"The scientific importance of this object lies in the fact that the neutron star is isolated," says Frederick M. Walter of the State University of New York (SUNY), in Stony Brook, NY. "It appears to be hot, not because it is accreting hydrogen gas as it moves through space, but because it is still young and cooling off. Since we know its approximate age, we can test how fast neutron stars cool off. Because this is the closest and brightest of the few known isolated neutron stars, it is the easiest to study and is an excellent test bed for nuclear astrophysical theories."

The neutron star's wayward trajectory was caught in three Hubble snapshots taken in 1996 and 1999. The three Hubble images show that the star moves across the sky with a characteristic apparent "wobble" (a reflection of the Earth's own orbital motion, an effect called parallax), which is expected of an object located about 200 light-years away.

In addition, the observations reveal that the neutron star is streaking across the sky from west to east at a rate of 1/3 of an arc second per year. (An arc second is a unit of angular measure. There are 3,600 arc seconds in a degree and 360 degrees in a full circle.) In 5,400 years, RX J185635-3754 travels a distance equal to the diameter of the Moon. Although this apparent motion may seem slow, it is actually one of the fastest moving stars in the sky. The fastest, Barnard's star, moves 10 arc seconds each year). The apparent motion, combined with the distance, means that the neutron star is moving at a speed of about 240,000 miles per hour (389,000 kilometers per hour).

This neutron star may be approaching from a grouping of young stars in the constellation Scorpius. About 1 million years ago, a massive star in a binary star system exploded as a supernova, releasing its companion star, an ultra-hot, blue star now known as Zeta Ophiuchus, which is also zooming away from the region. Because 1 million years ago the neutron star and Zeta Ophiuchus were in about the same location in space, the neutron star may be the remnant of the original binary companion of Zeta Ophiuchus, the star which exploded.

The runaway neutron star was first reported in 1992, when astronomers detected a very bright source of X-ray emission with the Roentgen Satellite (ROSAT). Because it was not seen in optical light and appeared to be within 500 light-years of the Earth, Walter and S.J. Wolk (Stony Brook) and R. Neuhaeuser (Max-Plack-Institut fuer Extraterrestrische Physik) surmised that it was likely to be a neutron star, a hot, dense stellar corpse with a six-mile radius.

Four years later, Stony Brook astronomers Walter and L.D. Matthews reported the optical identification of the star using the Hubble telescope. The object is very faint (26th magnitude or about 20 billion times fainter than the bright star Vega), and has a blue color. The blue color indicates that the object is hot, as expected from the bright X-ray emission. The temperature is about 1 million degrees Fahrenheit (600,000 degrees Kelvin). In September 2000, images taken with the European Southern Observatory's Very Large Telescope showed a small, cone-shaped "bowshock" in front of the neutron star, created as the star plowed through interstellar space.

The Hubble results have been accepted for publication in the Astrophysical Journal.

Note: Images can be found at http://oposite.stsci.edu/pubinfo/pr/2000/35/pr-photos.html


Story Source:

The above story is based on materials provided by Space Telescope Science Institute. Note: Materials may be edited for content and length.


Cite This Page:

Space Telescope Science Institute. "Hubble Sees Bare Neutron Star Streaking Across Space." ScienceDaily. ScienceDaily, 13 November 2000. <www.sciencedaily.com/releases/2000/11/001113071852.htm>.
Space Telescope Science Institute. (2000, November 13). Hubble Sees Bare Neutron Star Streaking Across Space. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2000/11/001113071852.htm
Space Telescope Science Institute. "Hubble Sees Bare Neutron Star Streaking Across Space." ScienceDaily. www.sciencedaily.com/releases/2000/11/001113071852.htm (accessed October 24, 2014).

Share This



More Space & Time News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: China Launches Moon Orbiter

Raw: China Launches Moon Orbiter

AP (Oct. 24, 2014) — China launched an experimental spacecraft Friday to fly around the moon and back to Earth in preparation for the country's first unmanned return trip to the lunar surface. (Oct. 24) Video provided by AP
Powered by NewsLook.com
China Prepares Unmanned Mission To Lunar Orbit

China Prepares Unmanned Mission To Lunar Orbit

Newsy (Oct. 23, 2014) — The mission is China's next step toward automated sample-return missions and eventual manned missions to the moon. Video provided by Newsy
Powered by NewsLook.com
Russian Cosmonauts Kick Off Final Spacewalk of 2014

Russian Cosmonauts Kick Off Final Spacewalk of 2014

Reuters - US Online Video (Oct. 22, 2014) — Russian cosmonauts Maxim Suraev and Alexander Samokutyaev step outside the International Space Station to perform work on the exterior of the station's Russian module. Rough Cut (no reporter narration) Video provided by Reuters
Powered by NewsLook.com
Comet Siding Spring Grazes Mars' Atmosphere

Comet Siding Spring Grazes Mars' Atmosphere

Newsy (Oct. 19, 2014) — A comet from the farthest reaches of the solar system passed extremely close to Mars this weekend, giving astronomers a rare opportunity to study it. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins