2019-06-01_All_About_Space

topic as astronomers around the world lock in on

extrasolar planet – or exoplanet – research. These

astronomers are not only looking for a ‘new

figureoutwhatkindof

mmodate planets and

ehiddenawayfromus

sual planetary system

for many years before

vinced they were out there.

exoplanets were found

second pulsar named PSR

me2,300lightyearsaway.

er ‘pulsar planets’, doomed

at orbit a dead star, were

rgeist (PSR B1257+12 c) and

betor (PSR B1257+12 d),

nounced by astronomers

ksander Wolszczan and

Frailon9January1992.

These two planets orbit the pulsar at roughly the

samedistancethatMercuryorbitstheSun.

However, there are not many other known pulsar

planets, as Dr Dimitri Veras, an assistant professor

attheUniversityofWarwick,UK,tellsAll About

Space:“Atypeofdeadstarwhichdidexperience

asupernovaiscalledapulsar,andatotaloffour

planets are known to orbit pulsars.” It is not much of

asurprisethatsuchasmallnumberoftheseplanets

exist due to the incredibly hostile nature of their

environment.Apulsaristhelaststageofamassive

star’s life, as long as the star originally had four- to

eight-times the mass of the Sun. After billions of

years, but a shorter time period than our Sun, the

star will explode as a supernova and leave behind

its dense, powerful core, known as a neutron star. A

neutron star can rotate rapidly, sending out jets of

material and radiation from its poles. If Earth is in

their line of sight astronomers pick up these rapid

f lashes of light, known as pulsars.

Life cy

The mass of a stellar object will

determine its evolution

tar

of the gas and dust

clump, and gravity

entum of spin will

formation in the

protostar.

3 Massive Star

Stars that have accumulated mass of at

leasteight-timesthatof our Sunwilllive

theirlivesasamassivestar forroughly

tens of millions of years.

5 Supernova

When the star bec

unstable it will

inevitably explode

a spectacular fashi

This will cast its

layers into the cos

as a supernova.

6 Black hole

If the star was more than

eight-times the mass of the Sun, a

blackholeislikelytoresideafter

the supernova.

7 Neutron star/pulsar

If the star was between four- and

eight-times the mass of the Sun a

neutronstarwillbeleftoverfrom

the supernova.

8 Small star

A relatively small star is

around the same mass of the

Sun and will have a life span

of about 10 billion years.

9 Red giant star

A similar puffing effect will

occur to a Sun-like star in which

the outer layers will expand by

illi f kilometres.

Below: The

Sun has

provided y

Earth’, they are trying to

environments can accom

how many exoplanets are

in the universe.

The search for an unus

did not take longat all –f

astronomers were conv

Thefirst confirmed

to orbit themillis

B1257+12 som

The first-eve

worlds tha

Polter

Pho

ann

Ale

Dale

the kindest

conditionsfor

life tothrive

on Earth

tar’s

life begins as a cloud

ofgasanddust,before

gravity gets hold of it.

© NASA /JPL-Caltech; The Hubble Heritage Team; Nicholas Forder;

cleof aa

e la

Theesstartofanys

lifebeginsasaclo

f y

o

oooo ..

euttron star/pullsas r

mmilmlioonso

2 Protos

SSecS tionso

bbegbgin toc

anddmome

in star

mof a

4 Red supergiant star

When its hydrogen begins

to deplete the outer layers

of the star will puff out

due to an imbalance in

the radiation and

gravitational equilibrium.

10 Planetary

nebula

Once the fuel is

finally depleted

the outer

layers will be

expelled. Not as

extravagantly as

a supernova, but

as a planetary

nebula.

11 White dwarf

In the centre of the

planetary nebula is a

white dwarf, the remains

of a star that has used all

its hydrogen.

Phantom worlds