Universe Guide

30 Serpentis

30 Serpentis Facts

  • 30 Serpentis is a subgiant star that can be located in the constellation of Libra. The description is based on the spectral class.
  • 30 Serpentis is not part of the constellation outline but is within the borders of the constellation.
  • Based on the spectral type (A5IV) of the star, the star's colour is blue - white .
  • The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.
  • Using the most recent figures given by the 2007 Hipparcos data, the star is 176.21 light years away from us. Distance

30 Serpentis's Alternative Names

The Id of the star in the Yale Bright Star Catalogue is HR5875. HIP77464 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD141378.

Flamsteed designations are named after the creator, Sir John Flamsteed. Sir John named the stars in the constellation with a number and its latin name, this star's Flamsteed designation is 30 Serpentis. The Flamsteed name can be shortened to 30 Ser.

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-03 3829.

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

Location of 30 Serpentis

The location of the subgiant 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 30 Serpentis, the location is 15h 48m 56.81 and -03° 49` 06.7 .

Radial Velocity and Proper Motion of 30 Serpentis

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 7.42 ± 0.17 milliarcseconds/year towards the north and -30.22 ± 0.27 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 -16.40000 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 of 30 Serpentis

30 Serpentis Colour and Temperature

Based on the star's spectral type of A5IV , 30 Serpentis's colour and type is blue - white subgiant star. The star has a B-V Colour Index of 0.12 which means the star's temperature is about 8,298 Kelvin. The temperature was calculated using information from Morgans @ Uni.edu.

30 Serpentis 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 15.10 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.

30 Serpentis Radius

30 Serpentis estimated radius has been calculated as being 1.74 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,211,771.26.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 1.9095814448463211807754493776. The figure is derived at by using the formula from SDSS rather than peer reviewed papers. It has been known to produce widely incorrect figures.

30 Serpentis Apparent and Absolute Magnitudes

30 Serpentis has an apparent magnitude of 5.53 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 2.07 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.87. 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 30 Serpentis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 20.34000 which gave the calculated distance to 30 Serpentis as 160.36 light years away from Earth or 49.16 parsecs. If you want that in miles, it is about 942,696,364,843,723.70, based on 1 Ly = 5,878,625,373,183.61 miles.

In 2007, Hipparcos data was revised with a new parallax of 18.51000 which put 30 Serpentis at a distance of 176.21 light years or 54.02 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 11,142,347.19 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 7,357.00 Parsecs or 23,995.84 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Travel Time to 30 Serpentis

The time it will take to travel to this star is dependent on how fast you are going. U.G. has done some calculations as to how long it will take going at differing speeds. A note about the calculations, when I'm talking about years, I'm talking non-leap years only (365 days).

The New Horizons space probe is the fastest probe that we've sent into space at the time of writing. Its primary mission was to visit Pluto which at the time of launch (2006), Pluto was still a planet.

DescriptionSpeed (m.p.h.)Time (years)
Airbus A380736160,556,190.48
Speed of Sound (Mach 1)767.269154,012,942.26
Concorde (Mach 2)1,534.5477,006,370.77
New Horizons Probe33,0003,580,889.58
Speed of Light670,616,629.00176.21

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 30 Serpentis Facts and Figures

Visual Facts

Primary / Proper / Traditional Name30 Serpentis
Alternative NamesHD 141378, HIP 77464, HR 5875, 30 Ser, BD-03 3829
Spectral TypeA5IV
Constellation's Main StarNo
Multiple Star SystemNo / Unknown
Star TypeSubgiant Star
GalaxyMilky Way
Absolute Magnitude 2.07 / 1.87
Visual / Apparent Magnitude5.53
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)15h 48m 56.81
Declination (Dec.)-03° 49` 06.7
Galactic Latitude37.18138165 degrees
Galactic Longitude4.07976398 degrees
1997 Distance from Earth20.34000 Parallax (milliarcseconds)
 160.36 Light Years
 49.16 Parsecs
2007 Distance from Earth18.51000 Parallax (milliarcseconds)
 176.21 Light Years
 54.02 Parsecs
 11,142,347.19 Astronomical Units
Galacto-Centric Distance23,995.84 Light Years / 7,357.00 Parsecs
Proper Motion Dec.7.42000 ± 0.17000 milliarcseconds/year
Proper Motion RA.-30.22000 ± 0.27000 milliarcseconds/year
B-V Index0.12
Radial Velocity-16.40000 ± 2.90 km/s
Semi-Major Axis8063.0000000
Stellar Luminosity (Lsun)15.1000000

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Estimated Calculated Facts

Radius (x the Sun)1.91
Effective Temperature8,298 Kelvin

Sources and Links

SIMBAD SourceLink

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