APOD: A Triple Star is Born (2016 Dec 02)

Comments and questions about the APOD on the main view screen.
Post Reply
User avatar
APOD Robot
Otto Posterman
Posts: 5345
Joined: Fri Dec 04, 2009 3:27 am
Contact:

APOD: A Triple Star is Born (2016 Dec 02)

Post by APOD Robot » Fri Dec 02, 2016 5:05 am

Image A Triple Star is Born

Explanation: A triple star system is forming, enshrouded within this dusty natal disk some 750 light-years away in the Perseus molecular cloud. Imaged at millimeter wavelengths by the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, the extreme close-up shows two protostars separated by a mere 61 AU (1 AU is the Earth-Sun distance) with a third 183 AU from the central protostar. The ALMA image also reveals a clear spiral structure indicating instability and fragmentation led to the multiple protostellar objects within the disk. Astronomers estimate that the system, cataloged as L1448 IRS3B, is less than 150,000 years old. Captured at an early phase, the starforming scenario is likely not at all uncommon, since almost half of all sun-like stars have at least one companion.

<< Previous APOD This Day in APOD Next APOD >>
[/b]

User avatar
neufer
Vacationer at Tralfamadore
Posts: 18805
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: A Triple Star is Born (2016 Dec 02)

Post by neufer » Fri Dec 02, 2016 5:21 am

Click to play embedded YouTube video.
Art Neuendorffer

User avatar
bystander
Apathetic Retiree
Posts: 21573
Joined: Mon Aug 28, 2006 2:06 pm
Location: Oklahoma

Re: APOD: A Triple Star is Born (2016 Dec 02)

Post by bystander » Fri Dec 02, 2016 6:12 am

Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor

User avatar
Chris Peterson
Abominable Snowman
Posts: 18113
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA
Contact:

Re: APOD: A Triple Star is Born (2016 Dec 02)

Post by Chris Peterson » Fri Dec 02, 2016 6:13 am

APOD Robot wrote:...the extreme close-up shows two protostars separated by a mere 61 AU (1 AU is the Earth-Sun distance) with a a third some 183 AU from the central protostar.
To give a better indication of resolution:
scaled.png
scaled.png (53.5 KiB) Viewed 6975 times
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
https://www.cloudbait.com

User avatar
geckzilla
Ocular Digitator
Posts: 9180
Joined: Wed Sep 12, 2007 12:42 pm
Location: Modesto, CA
Contact:

Re: APOD: A Triple Star is Born (2016 Dec 02)

Post by geckzilla » Fri Dec 02, 2016 6:45 am

[re: the figure Chris posted]
Presumably the little circle in the corner is to give us an indication of the point spread function. The resolution is just astonishing.

Edit:
From the paper:
The resolution of each image is shown with an ellipse(s) drawn in the lower right corner[...]
Hrm, well, I am not sure if I am right or wrong with my initial suspicion.
Just call me "geck" because "zilla" is like a last name.

Guest

Re: APOD: A Triple Star is Born (2016 Dec 02)

Post by Guest » Fri Dec 02, 2016 8:02 am

Is the apparent luminosity an indicator of size? And if so, is the larger of the three 'consuming' the other two or will at least one be ejected from the 'system'?

Boomer12k
:---[===] *
Posts: 2691
Joined: Sun Apr 22, 2007 12:07 am

Re: APOD: A Triple Star is Born (2016 Dec 02)

Post by Boomer12k » Fri Dec 02, 2016 8:42 am

Welcome to the Galaxy.... hope it goes well...

:---[===] *

mister T
Ensign
Posts: 28
Joined: Sat Oct 08, 2011 12:01 pm

Re: APOD: A Triple Star is Born (2016 Dec 02)

Post by mister T » Fri Dec 02, 2016 10:17 am

Are these protostars at the fusion producing stage yet, Or is their brightness the result of the energy released thru the accretion process?

User avatar
sym666
Ensign
Posts: 21
Joined: Fri Jun 16, 2006 6:11 am

Re: APOD: A Triple Star is Born (2016 Dec 02)

Post by sym666 » Fri Dec 02, 2016 11:36 am

Wonderful image. The proto-stars seem to be quite near one another, is it known what class of stars are they going to be? Is it possible that they will migrate at different distances?
Thanks

Alex_577

Re: APOD: A Triple Star is Born (2016 Dec 02)

Post by Alex_577 » Fri Dec 02, 2016 12:38 pm

The Adaptive Optics behind the instrument must be out of this world.

ManInFla

Re: APOD: A Triple Star is Born (2016 Dec 02)

Post by ManInFla » Fri Dec 02, 2016 12:58 pm

Small mistake here:
with a a third some
In 100 years, perhaps we can get a time-lapse version of this...

User avatar
geckzilla
Ocular Digitator
Posts: 9180
Joined: Wed Sep 12, 2007 12:42 pm
Location: Modesto, CA
Contact:

Re: APOD: A Triple Star is Born (2016 Dec 02)

Post by geckzilla » Sat Dec 03, 2016 2:43 am

Guest wrote:Is the apparent luminosity an indicator of size?
I've thought about this a bit, and I want to say that it is somewhat an idicator, but I also think that gaseous structures can also form structures which may look bigger and brighter at this resolution, but they might not necessarily be so. The brighter one could be fluffier or currently have a stream of gas that is broader and looks brighter.
Just call me "geck" because "zilla" is like a last name.

User avatar
Chris Peterson
Abominable Snowman
Posts: 18113
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA
Contact:

Re: APOD: A Triple Star is Born (2016 Dec 02)

Post by Chris Peterson » Sat Dec 03, 2016 3:52 am

Alex_577 wrote:The Adaptive Optics behind the instrument must be out of this world.
Although there are elements of the system that might be considered "adaptive", there is no adaptive optics system in the usual sense of the word. The ALMA system consists of an array of antennas that can be separated by kilometers, meaning that the resolution (0.01 arcsec) is essentially a function of nothing more than a very large aperture- just basic optical principles.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
https://www.cloudbait.com

User avatar
Ann
4725 Å
Posts: 13374
Joined: Sat May 29, 2010 5:33 am

Re: APOD: A Triple Star is Born (2016 Dec 02)

Post by Ann » Sat Dec 03, 2016 4:41 am

sym666 wrote:Wonderful image. The proto-stars seem to be quite near one another, is it known what class of stars are they going to be? Is it possible that they will migrate at different distances?
Thanks
I would love to know what spectral classes they are going to be.

I choose an orange-brown color to highlight the question from sym666, because I suspect that they are going to be quite small and cool stars that emit orange light. I believe they are going to be small simply because most stars that are already fully formed in the galaxy are small and cool, and also low-mass star formation is so much more common in the Milky Way than high-mass star formation. Also, when high-mass star formation occurs, it appears that many small stars form for every big and massive one.
The Sun adn 61 Cygni. Illustration: RJHall.
But at least it looks as if one of the stars is going to be bigger than the others, and two of the stars - those that are very close together - look like they are going to be considerably smaller. Perhaps the biggest star will be spectral class K, and the two others will be M-class dwarfs?

The picture at left by RJHall shows a size and color comparison between the Sun and the K-class components of 61 Cygni. I must point out that K-class stars are most definitely not as red as the picture suggests - they are in fact not red at all, but yellow-orange - and not even M-class stars are that red. Only carbon stars can be that red, and not even all carbon stars, either.

But I like the image. I think the triple star in today's APOD may grow into adulthood to become something like that.

Ann
Color Commentator

User avatar
MarkBour
Subtle Signal
Posts: 1377
Joined: Mon Aug 26, 2013 2:44 pm
Location: Illinois, USA

Re: APOD: A Triple Star is Born (2016 Dec 02)

Post by MarkBour » Sat Dec 03, 2016 5:13 am

geckzilla wrote:
Guest wrote:Is the apparent luminosity an indicator of size?
I've thought about this a bit, and I want to say that it is somewhat an idicator, but I also think that gaseous structures can also form structures which may look bigger and brighter at this resolution, but they might not necessarily be so. The brighter one could be fluffier or currently have a stream of gas that is broader and looks brighter.
One piece of evidence, the overall shape of the spiral structure, would tend to indicate that the greater mass is in its center. One reference in the caption estimates a mass of the two closer protostars totalling about the mass of our Sol, and the mass of the farther "3rd triplet" to be the least of the 3. Why it would appear brightest in this image, though, ... you got me. The signals are radio wavelength, rather than optical.

It is a spectacular image!
Mark Goldfain

User avatar
Ann
4725 Å
Posts: 13374
Joined: Sat May 29, 2010 5:33 am

Re: APOD: A Triple Star is Born (2016 Dec 02)

Post by Ann » Sat Dec 03, 2016 5:51 am

MarkBour wrote: One piece of evidence, the overall shape of the spiral structure, would tend to indicate that the greater mass is in its center. One reference in the caption estimates a mass of the two closer protostars totalling about the mass of our Sol, and the mass of the farther "3rd triplet" to be the least of the 3. Why it would appear brightest in this image, though, ... you got me. The signals are radio wavelength, rather than optical.

It is a spectacular image!
Fascinating!
Bright-looking yellow binary star Alpha Centauri (G2V + K1V) at 4 light-years,
bright blue binary Beta Centauri (B1III) at 400 light-years,
and (inset) ultra-faint Proxima Centauri (M6V) at 4 light-years.
Photo: Marco Lorenzi.
The ArXiv paper about the triple system wrote:

The inferred mass of the central pair of protostellar objects is ∼1 Msun, while the disk surrounding the three protostars has a total mass of ∼0.30 M$_{\sun}$. The tertiary protostar itself has a minimum mass of ∼0.085 Msun.
This clearly suggests that the two central stars have masses corresponding to late K or early M spectral classes. Most likely, at least one of the central stars will belong to spectral class K, while the other may become a bright-for-its-class main sequence M star.

The third star, if its current mass is a minimum of ∼0.085 solar masses, may become another Proxima Centauri! Really!

Ann
Color Commentator

User avatar
geckzilla
Ocular Digitator
Posts: 9180
Joined: Wed Sep 12, 2007 12:42 pm
Location: Modesto, CA
Contact:

Re: APOD: A Triple Star is Born (2016 Dec 02)

Post by geckzilla » Sat Dec 03, 2016 5:54 am

MarkBour wrote:
geckzilla wrote:
Guest wrote:Is the apparent luminosity an indicator of size?
I've thought about this a bit, and I want to say that it is somewhat an idicator, but I also think that gaseous structures can also form structures which may look bigger and brighter at this resolution, but they might not necessarily be so. The brighter one could be fluffier or currently have a stream of gas that is broader and looks brighter.
One piece of evidence, the overall shape of the spiral structure, would tend to indicate that the greater mass is in its center. One reference in the caption estimates a mass of the two closer protostars totalling about the mass of our Sol, and the mass of the farther "3rd triplet" to be the least of the 3. Why it would appear brightest in this image, though, ... you got me. The signals are radio wavelength, rather than optical.
I think the fluffy bits of gas in the accretion knot brighten the signal quite a bit compared with a star that is further along in the process that may have cleared more of the gas away from its area. At least, that's what it looks like in a simulation I was looking at:
https://www.youtube.com/watch?v=YbdwTwB8jtc
Just call me "geck" because "zilla" is like a last name.

User avatar
alter-ego
Serendipitous Sleuthhound
Posts: 1119
Joined: Mon Apr 21, 2008 4:51 am
Location: Redmond, WA

Re: APOD: A Triple Star is Born (2016 Dec 02)

Post by alter-ego » Sat Dec 03, 2016 7:15 am

Chris Peterson wrote:
Alex_577 wrote:The Adaptive Optics behind the instrument must be out of this world.
Although there are elements of the system that might be considered "adaptive", there is no adaptive optics system in the usual sense of the word. The ALMA system consists of an array of antennas that can be separated by kilometers, meaning that the resolution (0.01 arcsec) is essentially a function of nothing more than a very large aperture- just basic optical principles.
Interestingly, the radio-telescope equivalent of "adaptive optics" are critical to achieve long-baseline, high-resolution performance.
In these arrays, "adaptive optic" technology is electronic-based signal phase correction as opposed to mechanical mirror surface-deflection. At ALMA wavelengths, water vapor variations between antennas can significantly degrade the "seeing" at larger antenna separations as turbulent air does for larger optical telescopes. To improve image quality, ALMA uses Water Vapor Radiometers in each of the 12-m antennas to measure sky brightness (and ultimately the amount of water) within the antenna's field of view. From this data, good estimates can be made for the path length changes between the antennas, resulting in correcting individual signal phases so that they add up with minimum timing/phase error. Despite ALMA's dry location, I was surprised how bad ALMA seeing can be:
Phase Correction for ALMA with 183 GHz Water Vapour Radiometers wrote:The magnitude of the atmospheric fluctuations increases on longer baselines and, at millimetre and particularly submillimetre wavelengths, a baseline length is reached where the path variations are a large fraction of a wavelength and no useful astronomical signal can be reconstructed. This means that, without correction of the phase fluctuations, the angular resolution of the telescope will be limited by the effects of the atmosphere. The resolution achievable without correction is extremely variable, but a typical value is, coincidentally, similar to the optical seeing at good sites, i.e., around 0.5 arcseconds (see for example the analysis of ALMA site-testing data by Evans et al. 2003).
A pessimist is nothing more than an experienced optimist

User avatar
geckzilla
Ocular Digitator
Posts: 9180
Joined: Wed Sep 12, 2007 12:42 pm
Location: Modesto, CA
Contact:

Re: APOD: A Triple Star is Born (2016 Dec 02)

Post by geckzilla » Sat Dec 03, 2016 9:09 am

And here I am, getting all worked up over zodiacal glow.
Just call me "geck" because "zilla" is like a last name.

ygmarchi
Ensign
Posts: 37
Joined: Thu Dec 25, 2014 10:30 am
Contact:

Re: APOD: A Triple Star is Born (2016 Dec 02)

Post by ygmarchi » Sat Dec 03, 2016 11:49 am

These images are a true landmark in astronomy.

User avatar
neufer
Vacationer at Tralfamadore
Posts: 18805
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: A Triple Star is Born (2016 Dec 02)

Post by neufer » Sat Dec 03, 2016 12:33 pm

alter-ego wrote:
Phase Correction for ALMA with 183 GHz Water Vapour Radiometers wrote:The magnitude of the atmospheric fluctuations increases on longer baselines and, at millimetre and particularly submillimetre wavelengths, a baseline length is reached where the path variations are a large fraction of a wavelength and no useful astronomical signal can be reconstructed. This means that, without correction of the phase fluctuations, the angular resolution of the telescope will be limited by the effects of the atmosphere. The resolution achievable without correction is extremely variable, but a typical value is, coincidentally, similar to the optical seeing at good sites, i.e., around 0.5 arcseconds (see for example the analysis of ALMA site-testing data by Evans et al. 2003).
So a resolution of ~115 AU at 750 light-years then.

ALMA might as well have had her clothes stripped off by the atmospheric fluctuations of a passing water cloud.
Art Neuendorffer

Post Reply