APOD: LL Ori and the Orion Nebula (2018 Feb 18)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 4530
Joined: Fri Dec 04, 2009 3:27 am

APOD: LL Ori and the Orion Nebula (2018 Feb 18)

Post by APOD Robot » Sun Feb 18, 2018 5:05 am

Image LL Ori and the Orion Nebula

Explanation: Stars can make waves in the Orion Nebula's sea of gas and dust. This esthetic close-up of cosmic clouds and stellar winds features LL Orionis, interacting with the Orion Nebula flow. Adrift in Orion's stellar nursery and still in its formative years, variable star LL Orionis produces a wind more energetic than the wind from our own middle-aged Sun. As the fast stellar wind runs into slow moving gas a shock front is formed, analogous to the bow wave of a boat moving through water or a plane traveling at supersonic speed. The small, arcing, graceful structure just above and left of center is LL Ori's cosmic bow shock, measuring about half a light-year across. The slower gas is flowing away from the Orion Nebula's hot central star cluster, the Trapezium, located off the upper left corner of the picture. In three dimensions, LL Ori's wrap-around shock front is shaped like a bowl that appears brightest when viewed along the "bottom" edge. This beautiful painting-like photograph is part of a large mosaic view of the complex stellar nursery in Orion, filled with a myriad of fluid shapes associated with star formation.

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

HellCat
Ensign
Posts: 62
Joined: Wed Aug 05, 2009 1:30 am
Location: Cleveland, Ohio USA (Zulu -5)

Re: APOD: LL Ori and the Orion Nebula (2018 Feb 18)

Post by HellCat » Sun Feb 18, 2018 5:33 am

It's beautiful. Is that what is meant by "esthetic" - or did you mean, aesthetic?

https://duckduckgo.com/?q=define%3Aesth ... definition

User avatar
Chris Peterson
Abominable Snowman
Posts: 16323
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: LL Ori and the Orion Nebula (2018 Feb 18)

Post by Chris Peterson » Sun Feb 18, 2018 5:48 am

HellCat wrote:It's beautiful. Is that what is meant by "esthetic" - or did you mean, aesthetic?

https://duckduckgo.com/?q=define%3Aesth ... definition
"Esthetic" is a perfectly valid spelling.
Chris

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

NCTom

Re: APOD: LL Ori and the Orion Nebula (2018 Feb 18)

Post by NCTom » Sun Feb 18, 2018 12:09 pm

Though a thick haze to us, would a viewer from inside this nebula be able with the naked eye to detect any of the nebular material? My guess is it is still too rarefied.

User avatar
Ann
4725 Å
Posts: 11730
Joined: Sat May 29, 2010 5:33 am

Re: APOD: LL Ori and the Orion Nebula (2018 Feb 18)

Post by Ann » Sun Feb 18, 2018 12:30 pm

The delicate bow shock of LL Ori is a fascinating object, but there is another bow shock(?) in the picture. That is the rather bright bluish object at lower left, LP Ori or HD 36982. LP Ori is star of spectral class B1.5V, according to Simbad Astronomical Database. Is anything known about the bright nebula surrounding LP Ori?

Ann
Color Commentator

De58te
Science Officer
Posts: 430
Joined: Mon Sep 30, 2013 6:35 pm

Re: APOD: LL Ori and the Orion Nebula (2018 Feb 18)

Post by De58te » Sun Feb 18, 2018 12:36 pm

Hellcat, if you would have noticed in your DuckDuckGo link, the Merriam Webster Dictionary definition states, aesthetic British spelling, esthetic US spelling.

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

Re: APOD: LL Ori and the Orion Nebula (2018 Feb 18)

Post by Boomer12k » Sun Feb 18, 2018 1:08 pm

My Trapezium area shots. First with my Meade LX-90 8", and Second with my Celestron Evolution 6"....without a camera, the LX-90 has a better, more crisp, detailed view. Though with a 32mm eyepiece the E6 is still really nice.

I need to get me a wider angle lens, or I might be able to try my hand held...but it would be too jumpy I think...maybe a video...but I don't know about the detail as these were around 20 images of 15-45 seconds, I forget now....but M42 is probably my favorite place...

Today's image is just off of the top upper right area in my shots, I think.

:---[===] *
You do not have the required permissions to view the files attached to this post.

User avatar
neufer
Vacationer at Tralfamadore
Posts: 18750
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: LL Ori and the Orion Nebula (2018 Feb 18)

Post by neufer » Sun Feb 18, 2018 2:02 pm

Chris Peterson wrote:
HellCat wrote:
It's beautiful. Is that what is meant by "esthetic" - or did you mean, aesthetic?

https://duckduckgo.com/?q=define%3Aesth ... definition
"Esthetic" is a perfectly valid spelling.

:arrow: Or "athletic:"
https://en.wikipedia.org/wiki/Bootmobile wrote:
<<The L.L. Bean Bootmobile is a boot-shaped automobile made to celebrate L.L. Bean's 100th anniversary in 2012. It was introduced on January 17, 2012. It has visited cities with the intent of inspiring people to go outdoors. It is 13 feet tall, 20 feet long, and 7 feet wide, and is made of steel and fiberglass. It is based on a Ford F-250 Super Duty truck.>>
https://www.etymonline.com/word/aesthetic wrote:
aesthetic (n.) 1798, from German Ästhetisch (mid-18c.) or French esthétique (which is from German), ultimately from Greek aisthetikos "of or for perception by the senses, perceptive," of things, "perceptible," from aisthanesthai "to perceive (by the senses or by the mind), to feel."

Popularized in English by translations of Kant and used originally in the classically correct sense "science which treats of the conditions of sensuous perception" [OED]. Kant had tried to reclaim the word after Alexander Baumgarten had taken it in German to mean "criticism of taste" (1750s), but Baumgarten's sense attained popularity in English c. 1830s (despite scholarly resistance) and freed the word from philosophy. Walter Pater used it (1868) to describe the late 19c. movement that advocated "art for art's sake," which further blurred the sense. [Whewell had proposed callesthetics for "the science of the perception of the beautiful."

As an adjective by 1798 "of or pertaining to sensual perception;" 1821 as "of or pertaining to appreciation of the beautiful.">>
Art Neuendorffer

User avatar
Chris Peterson
Abominable Snowman
Posts: 16323
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: LL Ori and the Orion Nebula (2018 Feb 18)

Post by Chris Peterson » Sun Feb 18, 2018 3:10 pm

NCTom wrote:Though a thick haze to us, would a viewer from inside this nebula be able with the naked eye to detect any of the nebular material? My guess is it is still too rarefied.
It would certainly scatter or emit enough light to be visible, just like it does from our perspective. But I think from most viewpoints that visibility would largely manifest as a slightly brighter night sky. What there isn't is a lot of contrast between one region and another.
Chris

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

User avatar
neufer
Vacationer at Tralfamadore
Posts: 18750
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: LL Ori and the Orion Nebula (2018 Feb 18)

Post by neufer » Sun Feb 18, 2018 6:10 pm

Chris Peterson wrote:
NCTom wrote:
Though a thick haze to us, would a viewer from inside this nebula be able with the naked eye to detect any of the nebular material? My guess is it is still too rarefied.
It would certainly scatter or emit enough light to be visible, just like it does from our perspective. But I think from most viewpoints that visibility would largely manifest as a slightly brighter night sky. What there isn't is a lot of contrast between one region and another.
A denser version of the Gum Nebula perhaps: https://apod.nasa.gov/apod/ap090822.html
Art Neuendorffer

DAMGEM

Re: APOD: LL Ori and the Orion Nebula (2018 Feb 18)

Post by DAMGEM » Sun Feb 18, 2018 10:15 pm

ANYONE NOTICE THE IRREGULAR BLACK OBJECT IN THE UPPER LEFT.
LOOKS LIKE IT IS MUCH CLOSER THAN THE NEBULA AND MIGHT BE SOLID.
OR COULD IT BE A NEW SOLAR SYSTEM ABOUT TO HAPPEN.

User avatar
MarkBour
Subtle Signal
Posts: 1201
Joined: Mon Aug 26, 2013 2:44 pm
Location: Illinois, USA

Re: APOD: LL Ori and the Orion Nebula (2018 Feb 18)

Post by MarkBour » Mon Feb 19, 2018 2:35 am

Ann wrote:nebula
Ann wrote:The delicate bow shock of LL Ori is a fascinating object, but there is another bow shock(?) in the picture. That is the rather bright bluish object at lower left, LP Ori or HD 36982. LP Ori is star of spectral class B1.5V, according to Simbad Astronomical Database. Is anything known about the bright nebula surrounding LP Ori?
Ann
It certainly does have an appearance of a curtain draped over LP Ori. I don't suppose it will get called a bow shock because it does not have quite the right shape ... at this time. But if that star is indeed embedded in the cloud there, it would make sense that it is responsible for that shape.

Strike that: I don't think I was looking at it right! Although to me, the overall shape looks like it is "draped over" LP Ori (from our perspective and the image orientation), if I look at it more carefully, I believe the arc to its upper left very well could be forming the same bow shape and even about the same orientation as the shock visible for LL Ori. So I think you are right. The coloring looks bluish, as you said, which makes me guess it is a reflection area. You probably know more about LP Ori's size and strength of output(?)
DAMGEM wrote:ANYONE NOTICE THE IRREGULAR BLACK OBJECT IN THE UPPER LEFT.
LOOKS LIKE IT IS MUCH CLOSER THAN THE NEBULA AND MIGHT BE SOLID.
OR COULD IT BE A NEW SOLAR SYSTEM ABOUT TO HAPPEN.
Capture.JPG
I did, and was quite intrigued. It is straight up from LP Ori and up-and-to-the-left of LL Ori. Excerpt here, from the higher res image:

It actually reminds me of Oumuamua.
You do not have the required permissions to view the files attached to this post.
Mark Goldfain

User avatar
Ann
4725 Å
Posts: 11730
Joined: Sat May 29, 2010 5:33 am

Re: APOD: LL Ori and the Orion Nebula (2018 Feb 18)

Post by Ann » Mon Feb 19, 2018 6:00 am

MarkBour wrote:
Ann wrote:The delicate bow shock of LL Ori is a fascinating object, but there is another bow shock(?) in the picture. That is the rather bright bluish object at lower left, LP Ori or HD 36982. LP Ori is star of spectral class B1.5V, according to Simbad Astronomical Database. Is anything known about the bright nebula surrounding LP Ori?
Ann
It certainly does have an appearance of a curtain draped over LP Ori. I don't suppose it will get called a bow shock because it does not have quite the right shape ... at this time. But if that star is indeed embedded in the cloud there, it would make sense that it is responsible for that shape.

Strike that: I don't think I was looking at it right! Although to me, the overall shape looks like it is "draped over" LP Ori (from our perspective and the image orientation), if I look at it more carefully, I believe the arc to its upper left very well could be forming the same bow shape and even about the same orientation as the shock visible for LL Ori. So I think you are right. The coloring looks bluish, as you said, which makes me guess it is a reflection area. You probably know more about LP Ori's size and strength of output(?)
Thanks, Mark! Yes, I thought there are similarities between the obvious bow shock of LL Ori and the "draped blanket" over LP Ori. In both cases, the energetic outflow from the Trapezium could influence their respective shapes. The source of energy that is sculpting them seems to come from more or less the same direction.

As for LP Ori, it is a faint object, faint eighth magnitude. (LL Ori is obviously fainter, faint eleventh magnitude.) As I said before, the spectral class of LP Ori is B1.5V, or rather B1.5Vp, where "p" means "peculiar". The parallax of LP Ori was measured by the European satellite Tycho, which did a lousy job (or rather, it was unable to measure distances to objects as far away as LP Ori), so according to Tycho, LP Ori is a foreground object whose true visual luminosity is pretty much exactly one solar. Well, forget it. Obviously LP Ori is embedded in the Orion Nebula. Its apparent B-V index is about +0.1, which seems very reasonable, since LP Ori is definitely reddened by dust.

I believe that LP Ori is really quite young and therefore faint for its spectral class. I have noticed that other very young stars of spectral class B are fainter than their spectral class would suggest. The reason, I believe, is that stars are comparatively faint at the stage where they have recently got their hydrogen fusion going. I checked out a star just outside the Orion Nebula, HD 37303. This star, whose spectral class is B1V, is definitely likely to be older than LP Ori, but still young. HD 37303 is mostly unreddened and very blue, -0.20. The parallax of HD 37303 is 2.45 ± 0.48 milliarcseconds, suggesting a distance of around 1300 light-years. Its luminosity, as calculated from its parallax and apparent luminosity of 6.02, is more than 500 times solar. So what can we say about the likely luminosity of LP Ori? A hundred times solar?

Perhaps you, Mark, or some other math whiz could calculate the luminosity of LP Ori by assuming that its distance is about 1300 light-years and its apparent (and reddened) magnitude is about 8.4.

Personally I'm fascinated by the very dark cloud immediately to the left of LP Ori. My guess is that this dark cloud is either (and most likely) a remnant of the local cloud that gave birth to LP Ori, or else the outflows of the young object LP Ori has helped shape it or even make it. Well, that is not so likely.

Ann
Color Commentator

User avatar
Ann
4725 Å
Posts: 11730
Joined: Sat May 29, 2010 5:33 am

Re: APOD: LL Ori and the Orion Nebula (2018 Feb 18)

Post by Ann » Mon Feb 19, 2018 6:02 am

DAMGEM wrote:ANYONE NOTICE THE IRREGULAR BLACK OBJECT IN THE UPPER LEFT.
LOOKS LIKE IT IS MUCH CLOSER THAN THE NEBULA AND MIGHT BE SOLID.
OR COULD IT BE A NEW SOLAR SYSTEM ABOUT TO HAPPEN.
Indeed, that is a solar system in the making. It is probably not closer than the Orion Nebula, but a part of it.

Ann
Color Commentator

User avatar
MarkBour
Subtle Signal
Posts: 1201
Joined: Mon Aug 26, 2013 2:44 pm
Location: Illinois, USA

Re: APOD: LL Ori and the Orion Nebula (2018 Feb 18)

Post by MarkBour » Tue Feb 20, 2018 7:00 pm

Ann wrote: ... Perhaps you, Mark, or some other math whiz could calculate the luminosity of LP Ori by assuming that its distance is about 1300 light-years and its apparent (and reddened) magnitude is about 8.4.

Personally I'm fascinated by the very dark cloud immediately to the left of LP Ori. My guess is that this dark cloud is either (and most likely) a remnant of the local cloud that gave birth to LP Ori, or else the outflows of the young object LP Ori has helped shape it or even make it. Well, that is not so likely.

Ann
Not exactly a math whiz, though I enjoy playing with it. I think you gave me an Astronomy-student problem to try!

So, magnitude 8.4 = 10(0.4*8.4) = 2290.87, but that's too many significant digits, given the complexties of really comparing brightness, so I'll just say "about 2290" -- Vega's apparent brightness is 2290 that of LP Ori. But Vega is at 25 LY, while we're putting LP Ori at 1300 LY. By the inverse square law, we should adjust (1300/25)2 = 2704, so LP Ori's distance is making it appear 2704 times as dim as Vega's distance is. In other words, LP Ori's absolute magnitude should be 2704/2290 times Vega's. I think this is roughly the same as comparing luminosity. So, if Vega's luminosity is listed at 40.12 L☉ (in its Wikipedia reference chart), then that would put LP Ori at about 40(2704/2290) = 47 L☉.

--------------------

I'm glad you mentioned the dark region above and to its left. I wondered about that. Intuitively, it looks like it is a region of lesser gas density, but I don't trust that intuition. The darker patch seems to stretch, unevenly, clear to the edge of the image.
Mark Goldfain

User avatar
Ann
4725 Å
Posts: 11730
Joined: Sat May 29, 2010 5:33 am

Re: APOD: LL Ori and the Orion Nebula (2018 Feb 18)

Post by Ann » Tue Feb 20, 2018 9:22 pm

MarkBour wrote:
Ann wrote: ... Perhaps you, Mark, or some other math whiz could calculate the luminosity of LP Ori by assuming that its distance is about 1300 light-years and its apparent (and reddened) magnitude is about 8.4.

Personally I'm fascinated by the very dark cloud immediately to the left of LP Ori. My guess is that this dark cloud is either (and most likely) a remnant of the local cloud that gave birth to LP Ori, or else the outflows of the young object LP Ori has helped shape it or even make it. Well, that is not so likely.

Ann
Not exactly a math whiz, though I enjoy playing with it. I think you gave me an Astronomy-student problem to try!

So, magnitude 8.4 = 10(0.4*8.4) = 2290.87, but that's too many significant digits, given the complexties of really comparing brightness, so I'll just say "about 2290" -- Vega's apparent brightness is 2290 that of LP Ori. But Vega is at 25 LY, while we're putting LP Ori at 1300 LY. By the inverse square law, we should adjust (1300/25)2 = 2704, so LP Ori's distance is making it appear 2704 times as dim as Vega's distance is. In other words, LP Ori's absolute magnitude should be 2704/2290 times Vega's. I think this is roughly the same as comparing luminosity. So, if Vega's luminosity is listed at 40.12 L☉ (in its Wikipedia reference chart), then that would put LP Ori at about 40(2704/2290) = 47 L☉.

--------------------

I'm glad you mentioned the dark region above and to its left. I wondered about that. Intuitively, it looks like it is a region of lesser gas density, but I don't trust that intuition. The darker patch seems to stretch, unevenly, clear to the edge of the image.
Thanks, Mark! That is really helpful, and even I can understand it (mostly)! :D

Ann
Color Commentator