Our universe as we see it now has about 100 billion trillion stars, more stars than there are grains of sand on all the beaches of Earth. So it seems strange to think there was a time in the early universe, until a few hundred million years after the Big Bang, when there were no stars. Not a single one.
The first stars that formed in the universe were big, blue, and they burned fast, exploding as supernovae and seeding the universe with heavier elements like carbon and oxygen. These heavy elements… the elements that make planets and people… did not exist before the first stars. But once they were created, they led to the formation of the next generation of stars… and eventually to us.
All of these big first stars are long dead. But there are some very old stars that may have formed from the ashes of the very first stars. One of the easiest of these ancient stars to find is HD 140283, also known as the Methuselah Star. It’s only 190 light years away and shines at 7th magnitude in the constellation Libra, just north of the stars gamma and beta Librae. So with a star map, you can find it with pretty much any telescope or pair of binoculars when Libra is visible in the spring and summer months.
The Methuselah star is not much to look at… it looks like any other star. But like many things in astronomy, it’s far more interesting when you understand what you’re looking at. The Methuselah star is one of the elder statesmen of the universe. It’s been around since a few hundred million years after the Big Bang, and it has in its atmosphere some of the heavy elements cooked in the cores of the very first stars. By measuring the traces of heavy elements in the star– iron, oxygen, and so forth– astronomers can get a better idea of the size and lifecycle of the elusive “first stars” in the universe. This will help them look for these first stars using the next generation of telescopes, including the James Webb Space Telescope due for launch in 2018.
Methuselah Star is a subdwarf star that can be located in the constellation of Libra. The description is based on the spectral class. The star can not be seen by the naked eye, you need a telescope to see it.
Methuselah star is one of the more intriguing stars in our galaxy, the milky way and can be located in the constellation Libra. What makes this most interesting is that it has been calculated to be older than than the age of the universe. The generally accepted view of the universe's age is that it is about 13.7/8 billion years old. N.A.S.A had calculated the star to be around 14.5 billion years of age. However, previous estimates had put the star at being 16 billion years old, still much older than the star of the universe.
It is believed to have been born in another Galaxy which was cannibalised/merged with our own galaxy. It is also moving at a phenomenal speed, 800,000 miles which lends weight to the fact it came from another galaxy. It will take 1,500 years to move across an area of the night sky the width of the moon. The picture below shows the rough location of the star within the constellation. If you look at the star,it will appear as a red giant in its early stages.Ref: Space
Methuselah gets its name from the biblical character Methuselah who according to the bible lived for 969 years according to Genesis. It seemed appropriate to reference the character when they needed a name for the star. Ref: ThoughtCo
Methuselah Star's Alternative Names
HIP76976 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD140283. The Gliese ID of the star is GJ 1195. The star was added to the Gliese catalogue in 1970 by Richard van der Riet Woolley hence the GJ prefix rather than GL prefix.Star Names.
BD number is the number that the star was filed under in the Durchmusterung or Bonner Durchmusterung, a star catalogue that was put together by the Bonn Observatory between 1859 to 1903. The star's BD Number is BD-10 4149.
More details on star alternative names can be found at Star Names .
Location of Methuselah Star
The location of the star in the night sky is determined by the Right Ascension (R.A.) and Declination (Dec.), these are equivalent to the Longitude and Latitude on the Earth. The Right Ascension is how far expressed in time (hh:mm:ss) the star is along the celestial equator. If the R.A. is positive then its eastwards. The Declination is how far north or south the star is compared to the celestial equator and is expressed in degrees. For Methuselah Star, the location is 15h 43m 03.76 and -10° 55` 57.9 .
Radial Velocity and Proper Motion of Methuselah Star
All stars like planets orbit round a central spot, in the case of planets, its the central star such as the Sun. In the case of a star, its the galactic centre. The constellations that we see today will be different than they were 50,000 years ago or 50,000 years from now. Proper Motion details the movements of these stars and are measured in milliarcseconds. The star is moving -304.36 ± 0.46 miliarcseconds/year towards the north and -1,114.93 ± 0.68 miliarcseconds/year east if we saw them in the horizon.
The Radial Velocity, that is the speed at which the star is moving away/towards the Sun is -171.12 km/s with an error of about 0.29 km/s . When the value is negative then the star and the Sun are getting closer to one another, likewise, a positive number means that two stars are moving away. Its nothing to fear as the stars are so far apart, they won't collide in our life-time, if ever.
Methuselah Star Luminosity
Luminosity is the amount of energy that a star pumps out and its relative to the amount that our star, the Sun gives out. The figure of 4.59 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.
Physical Properties (Temperature) of Methuselah Star
Methuselah Star has a spectral type of sdF3. The star is 7,352.00 Parsecs from the Galactic Centre or terms of Light Years is 23,979.53 s. The star has a B-V Colour Index of 0.48 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 6,166 Kelvin.
Methuselah Star Radius has been calculated as being 1.70 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,183,988.03.km. If you need the diameter of the star, you just need to multiple the radius by 2. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 1.73. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures. The star's Iron Abundance is -2.27 with an error value of 9.99 Fe/H with the Sun has a value of 1 to put it into context.
Methuselah Star Apparent and Absolute Magnitudes
Methuselah Star has an apparent magnitude of 7.20 which is how bright we see the star from Earth. Apparent Magnitude is also known as Visual Magnitude. If you used the 1997 Parallax value, you would get an absolute magnitude of 3.41 If you used the 2007 Parallax value, you would get an absolute magnitude of 3.37. Magnitude, whether it be apparent/visual or absolute magnitude is measured by a number, the smaller the number, the brighter the Star is. Our own Sun is the brightest star and therefore has the lowest of all magnitudes, -26.74. A faint star will have a high number.
Distance to Methuselah Star
Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 17.44 which gave the calculated distance to Methuselah Star as 187.02 light years away from Earth or 57.34 parsecs. It would take a spaceship travelling at the speed of light, 187.02 years to get there. We don't have the technology or spaceship that can carry people over that distance yet.
In 2007, Hipparcos data was revised with a new parallax of 17.16 which put Methuselah Star at a distance of 190.07 light years or 58.28 parsecs. It should not be taken as though the star is moving closer or further away from us. It is purely that the distance was recalculated.
The star's Galacto-Centric Distance is 7,352.00 Parsecs or 23,979.53 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A
Methuselah Star Facts
Visual Facts
Primary / Proper / Traditional NameMethuselah Star
Alternative NamesHD 140283, HIP 76976, BD-10 4149, Gliese 1195
Spectral TypesdF3
Multiple Star SystemNo / Unknown
Star TypeSubdwarf Star
GalaxyMilky Way
ConstellationLibra
Absolute Magnitude3.41 / 3.37
Visual / Apparent Magnitude7.20
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)15h 43m 03.76
Declination (Dec.)-10° 55` 57.9
Galactic Latitude33.61 degrees
Galactic Longitude356.32 degrees
1997 Distance from Earth17.44 Parallax (milliarcseconds)
187.02 Light Years
57.34 Parsecs
2007 Distance from Earth17.16 Parallax (milliarcseconds)
190.07 Light Years
58.28 Parsecs
Galacto-Centric Distance23,979.53 Light Years / 7,352.00 Parsecs
Proper Motion Dec.-304.36 ± 0.46 milliarcseconds/year
Proper Motion RA.-1114.93 ± 0.68 milliarcseconds/year
B-V Index0.48
Radial Velocity-171.12 ± 0.29 km/s
Iron Abundance-2.27 ± 9.99 Fe/H
Eccentricity0.97
Semi-Major Axis2518.00
Stellar Luminosity (Lsun)4.59
Companions (Multi-Star and Exoplanets) Facts
Exoplanet CountNone/Unaware
Estimated Facts
Calculated Effective Temperature6,166 Kelvin
Scientists have known about the star HD 140283, informally nicknamed the Methuselah star, for more than 100 years, since it cruises across the sky at a relatively rapid clip. The star moves at about 800,000 mph (1.3 million km/h) and travels the width of the full moon in the sky every 1,500 years or so, researchers said. Its apparent magnitude is 7.223.
Previous research had estimated that the Milky Way galaxy's so-called "Methuselah star" is up to 16 billion years old. That's a problem, since most researchers agree that the Big Bang that created the universe occurred about 13.8 billion years ago.
Later estimates show that the star could be as old as 14.5 billion years (± 0.8 billion years), which is still it older than the universe's calculated age of about 13.8 billion years. This is an obvious dilemma.
How can a star be older than the universe itself?
 ){kind=link}
0 Comments