Just-released Hubble picture of nearest star

[Ann]

Click to view full size image

Proxima Centauri

hubblesite.org/newscenter wrote:

NOVEMBER 1, 2013: Proxima Centauri lies in the constellation of Centaurus (the Centaur), just over four light-years from Earth. Although it looks bright through the eye of the Hubble Space Telescope, as you might expect from the nearest star to the solar system, Proxima Centauri is not visible to the naked eye. Its average luminosity is very low, and it is quite small compared to other stars, at only about an eighth of the mass of the Sun. These observations were taken using Hubble's Wide Field and Planetary Camera 2 (WFPC2) in 1996. Proxima Centauri is actually part of a triple star system its two companions, Alpha Centauri A and B, lie out of frame.

Proxima Centauri is the nearest known star, at 4.227 ± 0.014 light-years from the Sun (and the Earth). Its visual luminosity is 0.00005510 ± 0.00000037 times that of the Sun. So it would take around 18,000 stars like Proxima Centauri to emit the visual light of just one star like the Sun! Of course, 18,000 stars like Proxima Centauri would contain about 2,000 times as much mass as the Sun, enough to make twenty stars like Eta Carina, whose bolometric luminosity (all-wavelenghts total luminosity) is more than a million times that of the Sun!

I have tried to find out what filters were used for this image, but I have been unsuccessful. Proxima Centauri is definitely a reddish star, similar in color to Betelgeuse, with a B-V index of about +1.8.

(So how many stars like Proxima would it take to emit as much visual light as Betelgeuse? The answer to that question depends critically on how well we are able to measure the distance to and reddening of Betelgeuse, but if we assume that the refined Hipparcos distance to Betelgeuse is correct and that there is negligible reddening, it would take about 230,000,000 little red runts like Proxima to emit as much light as the red supergiant of Orion!)

Ann

[rstevenson]

I find this an odd way to show Proxima Centauri to its adoring public. As they say on the linked page, "Although by cosmic standards it is a close neighbor, Proxima Centauri remains a point-like object even using Hubble's eagle-eyed vision, ... ." So why do they offer us a huge bright blob and flare instead? Surely a shorter exposure could have rendered the star in a somewhat more realistic way, if not as just a point.

Rob

[neufer]

[b][color=#0000FF]The two bright stars are (left) Alpha Centauri and (right) Beta Centauri. The faint red star in the center of the red circle is Proxima Centauri. Taken with Canon 85mm f/1.8 lens with 11 frames stacked, each frame exposed 30 seconds.[/color][/b]

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I find this an odd way to show Proxima Centauri to its adoring public. As they say on the linked page, "Although by cosmic standards it is a close neighbor, Proxima Centauri remains a point-like object even using Hubble's eagle-eyed vision, ... ." So why do they offer us a huge bright blob and flare instead? Surely a shorter exposure could have rendered the star in a somewhat more realistic way, if not as just a point.

[rstevenson]

Yes, I have other pictures of Proxima Centauri on hand, but I was commenting on that particular Hubble picture, just released by hubblesite.org.

Rob

[neufer]

Yes, I have other pictures of Proxima Centauri on hand, but I was commenting on that particular Hubble picture, just released by hubblesite.org.

And my point was that Proxima Centauri is not just a point and I would think that all the Proxima Centaurians down in the center of Proxima Centauri would appreciate the Hubble portrait.

[Chris Peterson]

I find this an odd way to show Proxima Centauri to its adoring public. As they say on the linked page, "Although by cosmic standards it is a close neighbor, Proxima Centauri remains a point-like object even using Hubble's eagle-eyed vision, ... ." So why do they offer us a huge bright blob and flare instead? Surely a shorter exposure could have rendered the star in a somewhat more realistic way, if not as just a point.

I agree. That is a truly ugly image. Why would they want to release an image that emphasizes the optical limitations of the HST? Diffraction, mirror roughness, scatter, saturation. Yuck.

[Beyond]

Yuck

Now that is a scientific term with Great meaning, that hardly anyone would have trouble understanding.

[neufer]

Yuck

Now that is a scientific term with Great meaning, that hardly anyone would have trouble understanding.

Click to play embedded YouTube video.

<<Mr. Yuk is a trademarked graphic image, created by the Children's Hospital of Pittsburgh, and widely employed in the United States in labeling of substances that are poisonous if ingested. In order to help children learn to avoid ingesting poisons, Mr. Yuk was conceived by Dr. Richard Moriarty, a pediatrician and clinical professor of pediatrics at the University of Pittsburgh School of Medicine who founded the Pittsburgh Poison Center and the National Poison Center Network. In Pittsburgh, the skull and crossbones previously used was not terribly helpful, because the Jolly Roger was the mascot for the local baseball team, the Pittsburgh Pirates. The color was chosen when Moriarty was showing different colors to students, and the green that was chosen was christened "Yucky!" by a young child. Hence, the name and the color. The design for Mr. Yuk was created by Wendy Courtney Brown, then a 4th grade student at Liberty Elementary in Weirton, West Virginia, as part of a Pittsburgh Poison Control design contest.>>

[geckzilla]

The filters used were most likely f814w and f675w. That's what's in the archive, anyway. Surprisingly, there are a lot of people who like the big diffraction spikes and bloom from bright stars, possibly because they are misunderstanding what they are viewing. Many people no doubt think that the CCD bloom is a view of the star itself. I watched a video that a comet ISON conspiracy theorist made (I try to keep up to date on my crackpots so I can quickly dispose of them at the forum...) and while he did a good thing by going to the original archive images he completely misinterpreted what he was viewing. He actually thought that an annular flare around a similarly bright star was a coronal mass ejection. As if we can observe CME's from any star other than our own!

[Ann]

geckzilla wrote:

As if we can observe CME's from any star other than our own!

Indeed... so I need to apologize for calling Proxima Centauri the nearest star!!!

Ann

[neufer]

"For many days, before the end of our Earth, people would look into the night sky and notice a star, increasingly bright and increasingly near...As the star approaches us, the weather will change. The great polar fields of the north and south will rot and divide and the seas will turn warm...And while the flash of our beginning has not yet traveled the light-years into the distance, has not yet been seen by planets deep within the other galaxies, you will disappear into the blackness of the space from which we came - destroyed, as we began, in a burst of gas and fire. The heavens are still and cold once more. In all the immensity of our universe and the galaxies beyond, the earth will not be missed. Through the infinite reaches of space, the problems of man seem trivial and naive indeed, and man existing alone seems himself an episode of little consequence."

[bystander]

New shot of Proxima Centauri, our nearest neighbour
ESA/HEIC Hubble Picture of the Week | 2013 Oct 28

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Shining brightly in this Hubble image is our closest stellar neighbour: Proxima Centauri.

Proxima Centauri lies in the constellation of Centaurus (The Centaur), just over four light-years from Earth. Although it looks bright through the eye of Hubble, as you might expect from the nearest star to the Solar System, Proxima Centauri is not visible to the naked eye. Its average luminosity is very low, and it is quite small compared to other stars, at only about an eighth of the mass of the Sun.

However, on occasion, its brightness increases. Proxima is what is known as a “flare star”, meaning that convection processes within the star’s body make it prone to random and dramatic changes in brightness. The convection processes not only trigger brilliant bursts of starlight but, combined with other factors, mean that Proxima Centauri is in for a very long life. Astronomers predict that this star will remain middle-aged — or a “main sequence” star in astronomical terms — for another four trillion years, some 300 times the age of the current Universe.

These observations were taken using Hubble’s Wide Field and Planetary Camera 2 (WFPC2). Proxima Centauri is actually part of a triple star system — its two companions, Alpha Centauri A and B, lie out of frame.

Although by cosmic standards it is a close neighbour, Proxima Centauri remains a point-like object even using Hubble’s eagle-eyed vision, hinting at the vast scale of the Universe around us.

Credit: ESA/Hubble & NASA

<< Previous ESA/HEIC Hubble POTW

I have tried to find out what filters were used for this image, but I have been unsuccessful.

Code: Select all

Colours & filters

Band		 Wavelength	Telescope
Infrared
I (orange) 	814 nm 	HST/WFPC2
Optical
R (cyan)   	675 nm 	HST/WFPC2