Astronomy

ASTRONEWS

Magnitude

Angular size

1.

5.60"

0.

8.45"

–1. 21

15.30"

• 
  
  
  
  2. 24.33"
  
  
  
  

April 1 June 1

Aug. 1

Feb. 1 Oct. 1 Dec. 1

1

2

0

Date

Jan. 1Feb. 1

March 1April 1May 1June 1

July 1Aug. 1 Sept. 1Oct. 1Nov. 1Dec. 1

Magnitude

5"

10"

15"

20"

25"

30"

Angular size

–1.32 –0.

15.81" 9.28"

FAST
FAC T

At its peak in August

2003, Mars shone

at magnitude –2.

and appeared 25.1"

in diameter.

14 ASTRONOMY • JANUARY 2018

GAINING WEIGHT. Astronomers bumped white dwarf 40 Eridani B’s mass from 0.42 to 0.57 solar mass

after carefully watching it interact with its red dwarf binary companion.

Even the fastest heavy metal drummers have

nothing on the pulsar PSR J0952–0607.

One of two rapidly rotating pulsars recently

discovered with the Low-Frequency Array

(LOFAR) telescope, PSR J0952-0607 emits more

than 700 “beats” (or radio pulses) per second.

That makes it the fastest pulsar in the Milky

Way and the second-fastest pulsar ever discov-

ered, after PSR J1748–2446ad in the Terzan 5

globular cluster. (See page 17 for more on

Terzan 5.) And the other newly discovered pul-

sar, PSR J1552+5437, is no slouch itself. It rotates

412 times per second.

Pulsars are a subclass of neutron stars,

which are objects left behind when a star goes

supernova but isn’t massive enough to form a

black hole. They emit radiation from their poles

as they spin, making them a sort of metronome

for the universe. These pulsars were discovered

using a new technique on the LOFAR telescope,

which looks in lower-frequency light than tra-

ditional pulsar searches.

Although it’s difficult to search for pulsars

at low frequencies because their light is dis-

rupted by intervening gas and dust, LOFAR has

The fastest pulsar in the Milky Way discovered

300

The number of asteroids the proposed Asteroid Touring

Nanosat Fleet could visit, using 50 tiny spacecraft.

instruments to filter out noise from any matter

between the telescope and the observing tar-

get. PSR J0952–0607 and PSR J1552+5437 are

both bright at low frequencies but dim at

higher frequencies, where traditional pulsar

searches occur — perhaps hinting at a

previously unseen population that could tell

us more about these extreme objects. — J.W.

NASA catches a huge solar flare

IN A FLASH. In early September, the Sun released its largest solar flare

since 2006. NASA’s Solar Dynamics Observatory easily spotted it, shown

here in the extreme ultraviolet (304 angstroms, or about 30 nanometers).

Solar flares typically erupt from or near sunspots — cooler areas on the

surface of the Sun that are associated with localized buildups in the star’s

powerful magnetic field. The magnetic field can become twisted and

looped as the Sun rotates, until finally these lines “snap” and trigger a

massive eruption of energy in many wavelengths across the spectrum,

including X-rays. — A.K.

ASTRONOMY

: ROEN KELLY

ASTRONOMY

: ROEN KELLY

AS GOOD AS IT GETS

RED PLANET REVIVAL. Mars puts on its best

show in 15 years during 2018. At its peak in late July,

it will shine at magnitude –2.8 — brighter than

any other point of light in the sky besides Venus

— and swell to an apparent diameter of 24.3". But

Mars will exceed magnitude –1.0 from late May to

mid-October and span more than 10" from late April

until mid-November. — Richard Talcott

RAPID FIRE. Pulsars such as PSR J0952–0607 are believed to spin so fast because they steal material from a

binary companion to boost their spin rates. Such rapidly rotating pulsars beam powerful radio and gamma-ray jets

from their poles, destroying those companions over time.

NASA/SDO/GODDARD