Astronomy

ASTRONEWS

Ecliptic in early June

Ecliptic in mid-August

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WWW.ASTRONOMY.COM 17

Researchers have been try-

ing to unlock the mysteries

of brown dwarfs ever since

their existence was confirmed

in 1995. Observations of

these distant, dim objects

from Earth are limited, but

multiple researchers plan

to use NASA’s upcoming

James Webb Space Telescope

(JWST) to eliminate some of

the uncertainty surrounding

brown dwarfs. Plans to study

their atmospheres and gain

insight into their formation

are in the works, with the end

goal of better understanding

the dividing line between

stars and planets.

Researchers at the

Université de Montréal will use

JWST to study SIMP0136, a

brown dwarf with a cloudy

atmosphere. Brown dwarfs’

atmospheres are best viewed

in infrared light, but because

Earth’s atmosphere absorbs

this light, studying SIMP

from the ground has proven

difficult. Webb’s space-based

instruments will enable

researchers to study the

clouds’ chemical composition

without obstruction.

Aleks Scholz, an astrono-

mer at the University of

St. Andrews in Scotland, plans

to use Webb to study

NGC 1333, a nebula in the

constellation Perseus.

NGC 1333 is a hotbed for

brown dwarfs, including

those weighing only about 5

to 6 Jupiter masses. (They are

usually much larger, tens of

times more massive than

Jupiter.) Webb’s infrared

viewing capabilities will

enable Scholz to study these

rare, dim, low-mass brown

dwarfs in much finer detail

than current ground

instruments.

Webb’s ability to detect

atmospheric molecules will

not only assist in identifying

common compounds among

brown dwarfs, but also could

help pinpoint whether these

worlds hold the elements

needed to support life. — A.J.

Webb to take

on brown

dwarfs

VENUS AT DUSK

Researchers at

the University of

Johannesburg recently

conducted a mineral analysis of the Hypatia

stone, an extraterrestrial rock fragment discov-

ered in Egypt in 1996. Their analysis found that

the stone’s mineral makeup is unlike any other

known object in our solar system.

The meteorite contains unusually high

amounts of carbon and low amounts of silicon,

a chemical composition opposite to that of

Earth, which has high amounts of silicon and

low amounts of carbon. Additionally, the grains

within Hypatia’s matrix (the stone inside which

dust grains are embedded) also have a unique

blend of phosphorus, nickel, and minute

amounts of iron. Because the ratio of elements

inside the grains differs from any other rocky

body in the solar system, researchers think the

grains were formed prior to the solar nebula

that birthed our planets.

Astronomers believe the solar nebula, a

massive cloud of dust and gas, produced the

Sun and the planets in our solar system. Planet

formation likely began as the nebula’s dust

began to clump together, a process long

believed to be homogenous. However,

Hypatia’s bizarre chemical composition and the

lack of silicate minerals in its matrix — which

are dominant in the compositions of Earth,

Venus, Mars, and most known meteorites —

cast doubt on this theory.

If Hypatia’s matrix is pre-solar, the question

of where it came from remains. And if it instead

formed from the same nebula that created the

planets, its never-before-seen makeup contra-

dicts the homogenous theory, leaving astrono-

mers to re-evaluate the distribution of

elements inside the nebula that formed our

solar system. — Amber Jorgenson

This meteorite’s

origin is mysterious

VIEWING THE INVISIBLE. The April 2017 campaign to image the supermassive black hole in the heart

of the Milky Way is expected to release its results later this year.

TINY LIGHTS. NGC 1333 is just one of many targets planned for

the upcoming James Webb Space Telescope. The young star cluster

associated with this nebula contains numerous brown dwarfs; Webb’s

infrared capabilities will allow astronomers to study these hard-to-see

failed stars in greater detail. NASA/CXC/JPL

From 40° north

latitude, Venus

peaks at an

altitude of 16°

in early June.

ASTRONOMY

: ROEN KELLY

THE “EVENING STAR.” Even at its dimmest, Venus shines nine times

brighter than the night sky’s brightest star, Sirius. But Venus stands out even

more when it lies far from the Sun. This chart plots the planet’s positions

for an observer at 40° north latitude an hour after sunset. Notice that Venus

reaches its peak altitude in late May and early June, more than two months

before its August 17 greatest elongation. That’s because the ecliptic — the

apparent path of the Sun and planets across our sky — makes a steeper

angle to the western horizon in springtime. — Richard Talcott

ODD BEGINNING. The Hypatia

stone, discovered by geologist

Aly Barakat in 1996, contains a

combination of chemicals and

minerals that doesn’t match our

early solar system. MARIO DI MARTINO/INAF

OSSERVATORIO ASTROFISICO DI TORINO

$

MILLION

The upper cost of a

new earth science mission line

recommended to NASA by the

National Academies of Sciences,

Engineering, and Medicine.