Gliese 710
Published on Feb 1, 2007 at 2:53 pm.
8 Comments.
Filed under stars.
In the direction of Serpens Cauda, there is a small unassuming star with the designation BD-01°3474, also known as Gliese 710. It is a small reddish star, only about half the mass of the Sun, and shining with only a bit more than 4% of the Sun’s light. It is what astronomers call a K7 dwarf. At a distance of about 50 lightyears, it appears only as magnitude 9.66 in our sky (The naked eye can only see a bit dimmer than magnitude 6 in good sky conditions). There really isn’t anything special or remarkable about this star, except for one thing: it is heading nearly right towards us at about 24 km/s (about 54,000 mph).
Gliese 710 isn’t on an exact collision course, but it will pass very close. In about 1.4 million years, it will be only about 1 lightyear from the Sun. Compare that with the current nearest star which is a shade over 4.2 lightyears away. At one lightlyear distant, this tiny star will shine at about magnitude 1.2 in our sky. That’s slightly brighter than the belt stars in Orion, and just dimmer than Aldebaran. It’s about the same brightness as Deneb or Fomalhaut.
But, becoming one of the brightest stars in the sky isn’t really the biggest news about this star. Our Solar System is believed to be surrounded by a swarm of small icy bodies called the Oort Cloud. When these bodies are disturbed in their orbits, they they can hurl down into the Solar System. There, they become comets. The outer edge of the Oort cloud is hypothesised to be somewhere around half a lightyear out. So, as Gliese 710 passes by, it will be nearly as close to these Oort cloud objects as is our own Sun. Gliese 710 has less mass, but it still has a LOT of mass (half the Sun’s mass) with which to disturb orbits. It will disturb a lot of orbits. In fact, this could produce a swarm of comets heading towards the inner Solar System. It might even be pretty for any inhabitants of the Solar System then, as you might expect a spectacular comet every couple years. There might even be almost always a naked eye comet somewhere in the sky. Very pretty indeed. Until one of them runs into us.
Granted, we are a small target, so such a collision is unlikely, but the more objects that are flying around the greater the chances. But, this is still a long way into the future.
-Astroprof
(Image: Palomar Digitized Sky Survey)
Centauri Dreams » Blog Archive » The Approach of Gliese 710 on February 3, 2007 at 7:31 am: 1
[…] The Astroprof’s Page takes a look at the interesting star Gliese 710, a K7 dwarf with a particular claim to distinction: it’s headed in the direction of our Sun at about 24 kilometers per second. Give it 1.4 million years and the star will have closed to within a light year of Sol, shining at a magnitude of 1.2 and disturbing the icy debris out in the Oort Cloud. A rain of comets moving into the inner system is the probable result. […]
Zot on February 11, 2007 at 3:14 pm: 2
I have alerted my wife and children ! We are selling all our securities and real estate as quickly as possible, and moving to a cave in Colorado.
John O on March 29, 2007 at 2:47 pm: 3
The subject Gliese 710 or other red dwarfs makes me wonder, what is least possible mass that a protostar could be and still begin fusion processes?
And roughly what fraction of the Sun’s diameter would this be?
Some things I’ve read suggest >=0.07M and about 0.25 solar diameter.
Astroprof on March 29, 2007 at 3:20 pm: 4
Yes, that is about the cutoff point for a low mass star, about 0.08M, or there-about.
Mark M on May 7, 2008 at 10:17 pm: 5
What are the chances of the star Gliese 710 coming to visit with outlying planets which would in turn be closer to the Oort cloud of our system? Perhaps even an oort belt of its own to contribute to an increase risk to our inner solar system ? Hubble views? New methods of determining existence of planets being worked out now effective here?
Mark M on May 16, 2008 at 1:26 pm: 6
Gliese 777a is listed at the JPL site nothing for Gliese 710. Gliese 777a has 2 planets. No mention of it coming this a way.
mark
Astroprof on May 19, 2008 at 12:54 pm: 7
The Gliese stars are simply small red dwarf stars. Not all of them are coming our way, nor do all of them have planets. It is possible that some of the passing stars may have planets and oort clouds, so there may be an exchange of bodies between stars now and then. Gliese 710 is still to pass far enough away, though, that such a scenario is unlikely with the Sun.
BearMaster on March 9, 2009 at 2:36 pm: 8
An Oort cloud is better than 99.9999% empty space. Sol and Gliese 710 passing through each others Oort clouds will probably have no worse effect than a couple of millenia of increased frequency of comets.
Probably.