Starship Asterisk*

Chris Peterson wrote: ↑Sun Dec 27, 2020 7:49 pm
Relevance?

neufer wrote: ↑Sun Dec 27, 2020 7:05 pm

Chris Peterson wrote: ↑Sun Dec 27, 2020 2:08 pm
Only rigid bodies can tidally lock.

The Earth has a rigid lithosphere. Its ocean is not rigid and its interior is not rigid.

Neither the oceans nor the interior (as long as it is fluid) could reasonably be seen as being able to be tidally locked to another body.

https://en.wikipedia.org/wiki/Beta_Lyrae wrote:

Double star system Beta Lyrae by Chesley Bonestell

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Beta Lyrae resolved using the CHARA array

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<<Beta Lyrae officially named Sheliak (Arabic: الشلياق), the traditional name of the system, is a multiple star system in the constellation of Lyra. Based on parallax measurements obtained during the Hipparcos mission, it is approximately 960 light-years distant from the Sun.

The variable luminosity of this system was discovered in 1784 by the British amateur astronomer John Goodricke. The orbital plane of this system is nearly aligned with the line of sight from the Earth, so the two stars periodically eclipse each other. This causes Beta Lyrae to regularly change its apparent magnitude from +3.2 to +4.4 over an orbital period of 12.9414 days. It forms the prototype of a class of ellipsoidal "contact" eclipsing binaries.

The two components are so close together that they cannot be resolved with optical telescopes, forming a spectroscopic binary. In 2008, the primary star and the accretion disk of the secondary star were resolved and imaged using the CHARA Array interferometer and the Michigan InfraRed Combiner (MIRC) in the near infrared H band, allowing the orbital elements to be computed for the first time.

In addition to the regular eclipses, the system shows smaller and slower variations in brightness. These are thought to be caused by changes in the accretion disc and are accompanied by variation in the profile and strength of spectral lines, particularly the emission lines. The variations are not regular but have been characterised with a period of 282 days.

Beta Lyrae Aa is a semidetached binary system made up of a stellar class B6-8 primary star and a secondary that is probably also a B-type star. The fainter, less massive star in the system was once the more massive member of the pair, which caused it to evolve away from the main sequence first and become a giant star. Because the pair are in a close orbit, as this star expanded into a giant it filled its Roche lobe and transferred most of its mass over to its companion.

The secondary, now more massive star is surrounded by an accretion disk from this mass transfer, with bipolar, jet-like features projecting perpendicular to the disk. This accretion disk blocks humans' view of the secondary star, lowering its apparent luminosity and making it difficult for astronomers to pinpoint what its stellar type is. The amount of mass being transferred between the two stars is about 2 × 10⁻⁵ solar masses per year, or the equivalent of the Sun's mass every 50,000 years, which results in an increase in orbital period of about 19 seconds each year. The spectrum of Beta Lyrae shows emission lines produced by the accretion disc. The disc produces around 20% of the brightness of the system.

In 2006, an adaptive optics survey detected a possible third companion, Beta Lyrae Ab. It was detected at 0.54" angular separation with a differential magnitude of +4.53. The difference in magnitudes suggests its spectral class is in the range B2-B5 V. This companion would make Beta Lyrae A a hierarchical triple system.>>

Chris Peterson wrote: ↑Sun Dec 27, 2020 2:08 pm
Only rigid bodies can tidally lock.

The Earth has a rigid lithosphere. Its ocean is not rigid and its interior is not rigid.

Neither the oceans nor the interior (as long as it is fluid) could reasonably be seen as being able to be tidally locked to another body.

https://en.wikipedia.org/wiki/Beta_Lyrae wrote:

Double star system Beta Lyrae by Chesley Bonestell

---

Beta Lyrae resolved using the CHARA array

---

<<Beta Lyrae officially named Sheliak (Arabic: الشلياق), the traditional name of the system, is a multiple star system in the constellation of Lyra. Based on parallax measurements obtained during the Hipparcos mission, it is approximately 960 light-years distant from the Sun.

The variable luminosity of this system was discovered in 1784 by the British amateur astronomer John Goodricke. The orbital plane of this system is nearly aligned with the line of sight from the Earth, so the two stars periodically eclipse each other. This causes Beta Lyrae to regularly change its apparent magnitude from +3.2 to +4.4 over an orbital period of 12.9414 days. It forms the prototype of a class of ellipsoidal "contact" eclipsing binaries.

The two components are so close together that they cannot be resolved with optical telescopes, forming a spectroscopic binary. In 2008, the primary star and the accretion disk of the secondary star were resolved and imaged using the CHARA Array interferometer and the Michigan InfraRed Combiner (MIRC) in the near infrared H band, allowing the orbital elements to be computed for the first time.

In addition to the regular eclipses, the system shows smaller and slower variations in brightness. These are thought to be caused by changes in the accretion disc and are accompanied by variation in the profile and strength of spectral lines, particularly the emission lines. The variations are not regular but have been characterised with a period of 282 days.

Beta Lyrae Aa is a semidetached binary system made up of a stellar class B6-8 primary star and a secondary that is probably also a B-type star. The fainter, less massive star in the system was once the more massive member of the pair, which caused it to evolve away from the main sequence first and become a giant star. Because the pair are in a close orbit, as this star expanded into a giant it filled its Roche lobe and transferred most of its mass over to its companion.

The secondary, now more massive star is surrounded by an accretion disk from this mass transfer, with bipolar, jet-like features projecting perpendicular to the disk. This accretion disk blocks humans' view of the secondary star, lowering its apparent luminosity and making it difficult for astronomers to pinpoint what its stellar type is. The amount of mass being transferred between the two stars is about 2 × 10⁻⁵ solar masses per year, or the equivalent of the Sun's mass every 50,000 years, which results in an increase in orbital period of about 19 seconds each year. The spectrum of Beta Lyrae shows emission lines produced by the accretion disc. The disc produces around 20% of the brightness of the system.

In 2006, an adaptive optics survey detected a possible third companion, Beta Lyrae Ab. It was detected at 0.54" angular separation with a differential magnitude of +4.53. The difference in magnitudes suggests its spectral class is in the range B2-B5 V. This companion would make Beta Lyrae A a hierarchical triple system.>>

VictorBorun wrote: ↑Sun Dec 27, 2020 1:29 pm

Chris Peterson wrote: ↑Sat Dec 26, 2020 5:21 am Only rigid bodies can tidally lock.

Are not the disk gas-rich galaxies rigid when:
1) alone and keeping themselves flat, smoothely whirling
2) run upon another body and conduct a mighty bing through their bodies

Is Earth rigid, is the Earth's ocean rigid? And are lito- and hydrospheres going to tidally lock with Moon and Sun?

Rigid enough though spherical enough too. Earth's future tidal lock with Sun is not out of the question.

Chris Peterson wrote: ↑Sat Dec 26, 2020 5:21 am Only rigid bodies can tidally lock.

MarkBour wrote: ↑Sun Dec 27, 2020 2:19 am

neufer wrote: ↑Sat Dec 26, 2020 1:25 pm

Chris Peterson wrote: ↑Sat Dec 26, 2020 5:21 am
Only rigid bodies can tidally lock.

Wouldn't you say that our ocean tides are tidally locked to the Moon

Ha! I suppose a tidal pool in Scotland, if it were large enough, could be called a tidal loch.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011JC007411 wrote:

Co‐tidal chart for Loch Ness from a numerical tidal model, indicating a small clockwise amphidromic system in the middle of the loch. Co‐tidal lines for Greenwich phase lag are shown every 60°, while co‐range lines are drawn every 0.15 mm.

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<<Loch Ness, located along the Great Glen fault, in the north of Scotland, is approximately 37 km long, has an average width of 1.6 km, and a maximum depth of 227 m. It aligns 38° east of north, approximately southwest to northeast, and at its northern end is connected to the tidal Moray Firth and North Sea, by a short (∼13 km) length of the River Ness. At 16 m above mean sea level, Loch Ness is not directly influenced by the ocean tide. However, we have been able to observe small (mm) tides in the Loch due to direct gravitational tidal attraction, and due to the loading of the solid earth by the ocean tides of the adjacent seas. This is believed to be the first observation in a European lake of an astronomical tide primarily due to loading.

Figure 5 presents typical model findings indicating a largely standing wave character, with M2 difference between the two ends consistent with expectations from the applied potential, and with a clockwise amphidromic system in the middle. This exercise confirmed that a comparison of measurements to direct gravitational and loading potentials as in Figure 3b is a valid one. Amplitudes and phases from this model were used to confirm that the self‐loading due to Loch Ness tides mentioned above is negligible.>>

neufer wrote: ↑Sat Dec 26, 2020 1:25 pm

Chris Peterson wrote: ↑Sat Dec 26, 2020 5:21 am

VictorBorun wrote: ↑Sat Dec 26, 2020 5:06 am

Do I get it right: the disk galaxies in a binary system don't do a tidal lock. They pose like runaway disk saws about to saw each other in two.

Only rigid bodies can tidally lock.

Wouldn't you say that our ocean tides are tidally locked to the Moon

neufer wrote: ↑Sat Dec 26, 2020 1:25 pm

Chris Peterson wrote: ↑Sat Dec 26, 2020 5:21 am

VictorBorun wrote: ↑Sat Dec 26, 2020 5:06 am

Do I get it right: the disk galaxies in a binary system don't do a tidal lock. They pose like runaway disk saws about to saw each other in two.

Only rigid bodies can tidally lock.

Wouldn't you say that our ocean tides are tidally locked to the Moon :?:

Chris Peterson wrote: ↑Sat Dec 26, 2020 5:21 am

VictorBorun wrote: ↑Sat Dec 26, 2020 5:06 am

Ann wrote: ↑Thu Dec 24, 2020 7:37 am
The separation between NGC 1055 and M77 is about 442,000 light-years.

Do I get it right: the disk galaxies in a binary system don't do a tidal lock. They pose like runaway disk saws about to saw each other in two.

Only rigid bodies can tidally lock.

VictorBorun wrote: ↑Sat Dec 26, 2020 5:06 am

Ann wrote: ↑Thu Dec 24, 2020 7:37 am The separation between NGC 1055 and M77 is about 442,000 light-years.

Do I get it right: the disk galaxies in a binary system don't do a tidal lock. They pose like runaway disk saws about to saw each other in two.

Ann wrote: ↑Thu Dec 24, 2020 7:37 am The separation between NGC 1055 and M77 is about 442,000 light-years.

APOD Robot wrote:

With a smattering of even more distant background galaxies, the deep image also reveals a boxy halo that extends far above and below the central bluge and disk of NGC 1055. The halo itself is laced with faint, narrow structures, and could represent the mixed and spread out debris from a satellite galaxy disrupted by the larger spiral some 10 billion years ago.

Wikipedia wrote:

It is a binary system together with the bright spiral galaxy M77 (NGC 1068). These two are the largest galaxies of a small galaxy group that also includes NGC 1073, and five other small irregular galaxies.

Wikipedia wrote:
Based on the published red shift, (Hubble Constant of 62 km/s per Mpc) a rough distance estimate for NGC 1055 is 52 million light-years, with a diameter of about 115,800 light-years. The separation between NGC 1055 and M77 is about 442,000 light-years.

Wikipedia wrote:

NGC 1055 is a bright infrared and radio source, particularly in the wavelength for warm carbon monoxide. Astronomers believe that this results from unusually active star formation.