Universe Guide

70 Sagittarii

70 Sagittarii Facts

70 Sagittarii's Alternative Names

HIP89980 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD168574.

70 Sagittarii has alternative name(s) :- V4028 Sagittarii, V4901 Sgr, V4028 Sgr.

The Gould star designation is one that was designed by American astronomer, Benjamin Apthorp Gould. Gould stars are predominantly in the Southern and Equatorial constellations but do appear in northern constellations such as Bootes and Orion. The star has the designation 56 G. Sagittarii. There are no stars with a Gould designation in Ursa Major for example.

More details on objects' alternative names can be found at Star Names .

Location of 70 Sagittarii

The location of the giant 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 object is compared to the celestial equator and is expressed in degrees. For 70 Sagittarii, the location is 18h 21m 31.36 and -24° 54` 55.0 .

Radial Velocity and Proper Motion of 70 Sagittarii

Proper Motion

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 -2.04 ± 0.32 milliarcseconds/year towards the north and 3.83 ± 0.54 milliarcseconds/year east if we saw them in the horizon.

Radial Velocity

The Radial Velocity, that is the speed at which the star is moving away/towards the Sun is 3.40 km/s with an error of about 2.90 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.

Physical Properties (Colour, Temperature) of 70 Sagittarii

70 Sagittarii Colour and Temperature

70 Sagittarii has a spectral type of M3III. This means the star is a red giant star. The star has a B-V Colour Index of 1.82 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 2,806 Kelvin.

70 Sagittarii Radius

Radius has been calculated as being 81.42 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 56,653,651.98.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 74.60. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

70 Sagittarii Apparent and Absolute Magnitudes

70 Sagittarii has an apparent magnitude of 6.19 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 -1.57 If you used the 2007 Parallax value, you would get an absolute magnitude of -1.38. 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 70 Sagittarii

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 2.80 which gave the calculated distance to 70 Sagittarii as 1164.87 light years away from Earth or 357.14 parsecs. If you want that in miles, it is 6,265,967,999,022,667.40.

In 2007, Hipparcos data was revised with a new parallax of 3.06 which put 70 Sagittarii at a distance of 1065.89 light years or 326.80 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.

Using the 2007 distance, the star is roughly 67,406,868.98 Astronomical Units from the Earth/Sun give or take a few. An Astronomical Unit is the distance between Earth and the Sun. The number of A.U. is the number of times that the star is from the Earth compared to the Sun.

The star's Galacto-Centric Distance is 7,089.00 Parsecs or 23,121.72 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Time to Travel to 70 Sagittarii

A note about the calculations, when I'm talking about years, I'm talking non-leap years only (365 days).

If you were to drive there at about 120 m.p.h. in a car with an infinity engine so you didn't have to pull over for petrol, it would take you 57,065,286,153,836.50 hours or 6,514,302,072.36 years.

At the time of writing, the fastest probe so far created is the New Horizon probe which is travelling at a speed of 33,000 m.p.h. If the probe was travelling to 70 Sagittarii then it would take 207,510,131,468.50 hours / 23,688,371.17 years to get there. Speed Ref: N.A.S.A.

It would to take a spaceship journey travelling at the speed of light, 1164.87 years to get there. We don't have the technology or spaceship that can carry people over that distance yet.

Variable Type of 70 Sagittarii

The star is a pulsating Semi-Regular Star w variable type which means that its size changes over time. The Variable Type is usually named after the first star of that type to be spotted. 70 Sagittarii brightness ranges from a magnitude of 6.201 to a magnitude of 5.957 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.2 days (variability).

Source of Information

The source of the information if it has a Hip I.D. is from Simbad, the Hipparcos data library based at the University at Strasbourg, France. Hipparcos was a E.S.A. satellite operation launched in 1989 for four years. The items in red are values that I've calculated so they could well be wrong. Information regarding Metallicity and/or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

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Additional 70 Sagittarii Facts and Figures

Visual Facts

Primary / Proper / Traditional Name70 Sagittarii
Alternative NamesV4028 Sagittarii, V4901 Sgr, HD 168574, HIP 89980, 56 G. Sagittarii, V4028 Sgr
Spectral TypeM3III
Constellation's Main StarNo
Multiple Star SystemNo / Unknown
Star TypeGiant Star
GalaxyMilky Way
Absolute Magnitude -1.57 / -1.38
Visual / Apparent Magnitude6.19
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.) 18h 21m 31.36
Declination (Dec.)-24° 54` 55.0
Galactic Latitude-4.99 degrees
Galactic Longitude7.44 degrees
1997 Distance from Earth2.80 Parallax (milliarcseconds)
 1164.87 Light Years
 357.14 Parsecs
2007 Distance from Earth3.06 Parallax (milliarcseconds)
 1065.89 Light Years
 326.80 Parsecs
 67,406,868.98 Astronomical Units
Galacto-Centric Distance23,121.72 Light Years / 7,089.00 Parsecs
Proper Motion Dec.-2.04 ± 0.32 milliarcseconds/year
Proper Motion RA.3.83 ± 0.54 milliarcseconds/year
B-V Index1.82
Radial Velocity3.40 ± 2.90 km/s
Semi-Major Axis7823.00

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeSemi-Regular Star w
Mean Variability Period in Days0.192
Variable Magnitude Range (Brighter - Dimmer)5.957 - 6.201

Estimated Calculated Facts

Radius (x the Sun)74.60
Effective Temperature2,806 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Comments and Questions

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