Page 1 of 2

APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Tue Jun 25, 2019 4:11 am
by APOD Robot
Image 25 Brightest Stars in the Night Sky

Explanation: Do you know the names of some of the brightest stars? It's likely that you do, even though some bright stars have names so old they date back to near the beginning of written language. Many world cultures have their own names for the brightest stars, and it is culturally and historically important to remember them. In the interest of clear global communication, however, the International Astronomical Union (IAU) has begun to designate standardized star names. Featured above in true color are the 25 brightest stars in the night sky, currently as seen by humans, coupled with their IAU-recognized names. Some star names have interesting meanings, including Sirius ("the scorcher" in Latin), Vega ("falling" in Arabic), and Antares ("rival to Mars" in Greek). It's also likely that other of these bright star names are not familiar to you, even though familiar Polaris is too dim to make this list.

<< Previous APOD This Day in APOD Next APOD >>

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Tue Jun 25, 2019 4:38 am
by Ann
Fascinating! Has Tragoolchitr Jittasaiyapan taken all these pictures himself? They do seem to have been made in the same way.

As a color commentator, I must say that the star colors in most cases appear to be excellent. However, I note that a star like Altair (B-V = +0.22) looks bluer than a star like Hadar (B-V = -0.23). But I do realize that other wavelengths than B and V may affect the perceived color of a star, and also, atmospheric conditions vary, as well as the star's position in the sky, and all these things (and more) may affect the camera's reaction to the light from a star.

All in all, I love this APOD! Thank you!

Ann

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Tue Jun 25, 2019 10:24 am
by Galaxy Babe
Thank you for this. Are they supposed to be in order of brightness? If so, Arcturus should be #3 with Rigil Kentaurus at #4.

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Tue Jun 25, 2019 11:45 am
by orin stepanek
Starlight starbright; 25 brightest stars in sight! 8-)

Adhara

Posted: Tue Jun 25, 2019 1:44 pm
by neufer
https://en.wikipedia.org/wiki/Epsilon_Canis_Majoris wrote:
<<Despite being designated ε (epsilon), ε Canis Majoris (Epsilon CMa, ε CMa) is the second-brightest object in the constellation of Canis Major. Based upon parallax measurements obtained during the Hipparcos mission, it is about 430 light-years distant from the Sun. ε Canis Majoris bore the traditional name Adhara, derived from the Arabic word عذارى ‘aðāra’, "virgins".

Adhara belongs to the spectral classification B2. Its color is blue or blueish-white, due to the surface temperature of 22,200K. It emits a total radiation equal to 38,700 times that of the Sun. This star is the brightest-known extreme ultraviolet source in the night sky. It is the strongest source of photons capable of ionizing hydrogen atoms in interstellar gas near the Sun, and is very important in determining the ionization state of the Local Interstellar Cloud.

A few million years ago, Adhara was much closer to the Sun than it is at present, causing it to be a much brighter star in the night sky. About 4.7 million years ago, Adhara was 34 light-years from the Sun, and was the brightest star in the sky with a magnitude of –3.99. No other star has attained this brightness since, nor will any other star attain this brightness for at least five million years.
>>

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Tue Jun 25, 2019 1:48 pm
by Cousin Ricky
Galaxy Babe wrote: Tue Jun 25, 2019 10:24 am Thank you for this. Are they supposed to be in order of brightness? If so, Arcturus should be #3 with Rigil Kentaurus at #4.
Rigil Kentaurus is a double star, and Tragoolchitr photographed them as a unit. Considered as components, Alpha Cen A is #4, but Alpha Cen A and B combined are brighter than Arcturus.

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Tue Jun 25, 2019 1:52 pm
by Cousin Ricky
I never realized Shaula was so high in the rankings! I guess I it wasn’t on my radar because it just missed the 1st magnitude cutoff. So my next question is: how did it end up as a lambda?

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Tue Jun 25, 2019 1:57 pm
by starsurfer
Does anyone know what Zubenelgenubi means? :D

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Tue Jun 25, 2019 2:04 pm
by jrmbasso
Terrific site. Are any of the listed stars in the Southern Hemisphere?

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Tue Jun 25, 2019 2:06 pm
by Chris Peterson
jrmbasso wrote: Tue Jun 25, 2019 2:04 pm Terrific site. Are any of the listed stars in the Southern Hemisphere?
The brightest star in the sky, and the first one in this list! (And others as well.)

"something that touches the sky"

Posted: Tue Jun 25, 2019 2:57 pm
by neufer
starsurfer wrote: Tue Jun 25, 2019 1:57 pm
Does anyone know what Zubenelgenubi means? :D
https://en.wikipedia.org/wiki/Alpha_Librae wrote:


<<Zubenelgenubi, also rendered Zuben Elgenubi, derives from the Arabic ّالزُبَانَى الجَنُوبِي al-zubānā al-janūbiyy "the southern claw", which was coined before Libra was recognized as a constellation distinct from Scorpius. (Zubeneschamali, derived from the Arabic ّالزُبَانَى الشَمَالِي meaning "The Northern Claw".) The alternative name Kiffa Australis (Elkhiffa Australis) is a partial Latin translation of the Arabic al-kiffah al-janubiyyah الكفة الجنوبية "southern pan [of the scales]". Another name used in older astronomy texts, equivalent to "southern pan", was Lanx Australis.

Zubin (Persian: زوبین‎) is a Persian male given name (e.g., Zubin Mehta), which means short spear in Persian, literally meaning "something that touches the sky". The name originated in Iran, Iran. In Persian mythology, Zubin (also called: Zupin, Zhubin, Zhupin) was one of the warriors of Iran's army, famous for his courage. "Zubin" was also a weapon as well "a short spear that would be thrown to kill the enemy.>>

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Tue Jun 25, 2019 3:34 pm
by TheZuke!
Ann wrote: Tue Jun 25, 2019 4:38 am ...
As a color commentator,
...
In my book, you are THE color commentator on APOD!

B^)

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Tue Jun 25, 2019 4:13 pm
by neufer
Cousin Ricky wrote: Tue Jun 25, 2019 1:52 pm
I never realized Shaula was so high in the rankings! I guess I it wasn’t on my radar because it just missed the 1st magnitude cutoff.

So my next question is: how did it end up as a lambda?
At 37º declination Shaula was so low in the sky that it proved difficult to compare with other bright stars of Scorpius :?:
https://en.wikipedia.org/wiki/Lambda_Scorpii wrote:

<<Lambda Scorpii (λ Sco), formally named Shaula, is, despite being designated "λ" (Lambda), the second-brightest star system in the constellation of Scorpius. Shaula, which comes from the Arabic الشولاء al-šawlā´ meaning 'the raised [tail]', as it is found in the tail of Scorpius, the scorpion.

Lambda Scorpii is located some 570 light-years away from the Sun. Spectroscopic and interferometric observations have shown that it is actually a triple star system consisting of two B-type stars and a pre-main-sequence star. The primary star is a Beta Cephei variable star with rapid brightness changes of about a hundredth of a magnitude. The pre-main-sequence star has an orbital period of 6 days and the B companion has a period of 1053 days. The three stars lie in the same orbital plane, strongly suggesting that they were formed at the same time. The masses of the primary, pre-main-sequence star and the B companion are 14.5, 2.0 and 10.6 solar masses, respectively. The age of the system is estimated to be in the range 10–13 million years.>>

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Tue Jun 25, 2019 5:08 pm
by BDanielMayfield
An altogether most excellent APOD!

Apparently, the exposure times of the 25 different photos vary widely, since the contrast in apparent brightness isn't near as large as these actually appear to the eye. The apparent magnitudes range from Sirius' -1.46 (almost twice as bright as runner up Canopus at -0.74) down to 25th ranked Gacrux at mag +1.63. Seeing this set of star systems shown with a more realistic depiction of their differences in brightness would be an improvement on this already excellent work.

Bruce

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Tue Jun 25, 2019 5:49 pm
by Evenstar
How does Sol fit into the 25 brightest--I think it is way off the list?

Do any of these brightest have any exoplanets?

Thanks.

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Tue Jun 25, 2019 5:54 pm
by zendae1
Today's APOD sent me on a long mission: I wanted to see if there was one single distinguishing feature of each star. It wasn't easy, but I kinda succeeded. And some may be inaccurate; it's just what I found.
Gacrux - nearest red giant
Castor - a whopping 6 star amalgam
Shaula/Adhara - these have been discussed above
Mimosa - hottest out of the bunch
Deneb - brightest distant star
Fomalhaut - the loneliest star
Pollux - closest giant to the sun (I am assuming there is a difference between this and Gacrux)
Spica - a binary only 11 million miles apart
Antares - relatively young star nearing supernova
Aldebaran - most famous in mythology, literature, and music
Acrux - the star of Magellan
Altair - one of the few stars we have a pic of it's surface
Hadar - a binary approaching supernova
Betelgeuse - most variable magnitude
Achernar - the flattest star; it's egg-shaped
Procyon - has a dead white dwarf
Rigel - will be the brightest next to the moon when it goes supernova
Capella - it's xray emissions started xray stellar astronomy
Vega - the past, and the future's North Star
Arcturus - one of three flashing stars (all I could find)
Rigil Kentaurus - as we know, the closest star(s)
Canopus - rich in ancient culture with many names
Sirius - #1

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Tue Jun 25, 2019 5:57 pm
by Chris Peterson
Evenstar wrote: Tue Jun 25, 2019 5:49 pm How does Sol fit into the 25 brightest--I think it is way off the list?
Since we're talking apparent magnitude here, not absolute, Sol is way off the list to the upper left- over 25 magnitudes brighter than Sirius. That is, it is about 12 billion (12 x 109) times brighter.

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Tue Jun 25, 2019 6:06 pm
by Evenstar
What a surprise. Let's not talk apparent. Let's pretend we are on a planet in another solar system among these "brightest" stars. Where does the sun fit in?

Any exoplanets? Or are the brightest too bright to "see"?

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Tue Jun 25, 2019 6:17 pm
by BDanielMayfield
Cousin Ricky wrote: Tue Jun 25, 2019 1:48 pm Rigil Kentaurus is a double star, and Tragoolchitr photographed them as a unit. Considered as components, Alpha Cen A is #4, but Alpha Cen A and B combined are brighter than Arcturus.
Cousin Ricky's comment made me wonder how many of these stars are multiples. I did some research, and it turns out that most of these stars' light comes from more than one star (although a primary vastly dominates in most systems). This follows from the fact that the majority of all star systems are multiples.

Extra credit question, how many of the FOURTEEN multiples hidden in this group can you name? (There are actually at least fifteen multiple star systems in today's APOD, but Fomalhaut's two companions are distantly out of frame.)

Answer (with extra multiplicity info):
Sirius, Rigil Kentaurus (aka Alpha Cen, along with distant Proxima), Rigel (system of at least 4), Procyon, Achernar, Hadar (3), Acrux (6), Antares, Spica, Mimosa, Regulus (4), Adhara, Shaula, and Castor (6).

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Tue Jun 25, 2019 6:27 pm
by Chris Peterson
Evenstar wrote: Tue Jun 25, 2019 6:06 pm What a surprise. Let's not talk apparent. Let's pretend we are on a planet in another solar system among these "brightest" stars. Where does the sun fit in?
The Sun has an absolute magnitude of 4.83. You could look up the absolute magnitudes of the 25 stars here for comparison. For example, Sirius has an absolute magnitude of 1.4, making it 23 times more luminous than the Sun. Rigil Kentaurus has an absolute magnitude of 4.38, so only 1.5 times more luminous than the Sun. And Rigel is over 100,000 times more luminous.

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Tue Jun 25, 2019 6:36 pm
by BDanielMayfield
Ann wrote: Tue Jun 25, 2019 4:38 am Fascinating! Has Tragoolchitr Jittasaiyapan taken all these pictures himself? They do seem to have been made in the same way.
I wondered about that as well. Not to disparage this work, but couldn't this very informative grouping have been assembled from photos that are in the public domain?

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Tue Jun 25, 2019 7:16 pm
by BDanielMayfield
zendae1 wrote: Tue Jun 25, 2019 5:54 pm Today's APOD sent me on a long mission: I wanted to see if there was one single distinguishing feature of each star. It wasn't easy, but I kinda succeeded. And some may be inaccurate; it's just what I found.
Gacrux - nearest red giant
Castor - a whopping 6 star amalgam
Shaula/Adhara - these have been discussed above
Mimosa - hottest out of the bunch
Deneb - brightest distant star
Fomalhaut - the loneliest star
Pollux - closest giant to the sun (I am assuming there is a difference between this and Gacrux)
Spica - a binary only 11 million miles apart
Antares - relatively young star nearing supernova
Aldebaran - most famous in mythology, literature, and music
Acrux - the star of Magellan
Altair - one of the few stars we have a pic of it's surface
Hadar - a binary approaching supernova
Betelgeuse - most variable magnitude
Achernar - the flattest star; it's egg-shaped
Procyon - has a dead white dwarf
Rigel - will be the brightest next to the moon when it goes supernova
Capella - it's xray emissions started xray stellar astronomy
Vega - the past, and the future's North Star
Arcturus - one of three flashing stars (all I could find)
Rigil Kentaurus - as we know, the closest star(s)
Canopus - rich in ancient culture with many names
Sirius - #1
Nice list zendea1. The best APODs do often inspire additional research.

Bruce

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Tue Jun 25, 2019 10:32 pm
by BDanielMayfield
Evenstar wrote: Tue Jun 25, 2019 6:06 pm Any exoplanets? Or are the brightest too bright to "see"?
We now know enough to expect there to be exoplanets in just about ALL single star systems, but among this bright star set there is only one CONFIRMED exoplanet (so far), Pollux b.

Among the multiple star systems there is the confirmed Proxima b, although it doesn't lie inside the field of view of Alpha Cen's (Rigil Kentaurus) picture.

A few other systems in this group are strongly suspected of containing a planet or planets, such as Fomalhaut, Alpha Cen B and one or two more. Usually though confirmation of an exoplanet's existence comes not from "seeing" it (by direct imaging) but by carefully noting over time subtle changes in a star's light caused by the planet's orbit.

Bruce

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Wed Jun 26, 2019 3:33 am
by Ann
TheZuke! wrote: Tue Jun 25, 2019 3:34 pm
Ann wrote: Tue Jun 25, 2019 4:38 am ...
As a color commentator,
...
In my book, you are THE color commentator on APOD!

B^)
Thanks! :D

Ann

Re: APOD: 25 Brightest Stars in the Night Sky (2019 Jun 25)

Posted: Wed Jun 26, 2019 5:02 am
by Ann
Evenstar wrote: Tue Jun 25, 2019 6:06 pm What a surprise. Let's not talk apparent. Let's pretend we are on a planet in another solar system among these "brightest" stars. Where does the sun fit in?

Any exoplanets? Or are the brightest too bright to "see"?
All the stars on the list are intrinsically brighter than our Sun.

1) The intrinsically faintest of the 25 on the list is Rigil Kentaurus, which consists of a pair of stars, Alpha Centauri A and Alpha Centauri B. Actually, Alpha Centauri B is fainter than the Sun, about 0.5 L, but Alpha Centauri A, the "solar twin", is 1.5 L. Alpha Centauri A is the same spectral class as the Sun, G2V, but it is a little bit more massive, 1.1 M. Alpha Centauri B is 0.92 M and spectral class K1V. So why does Alpha Centauri, Rigil Kentaurus, look so bright in our night skies? It is because this triple star (including ultra-faint Proxima Centauri) is the most nearby of all stars, except the Sun, of course. The distance to Alpha Centauri is only 4.4 light-years.

I think, although I'm not sure, that Alpha Centauri B has a planet.

2) So, counting backwards and beginning with the faintest ones on the list, the next one after Alpha Centauri would be Procyon (Procyon), spectral class F5IV-V and a little hotter than the Sun (but not much hotter), with a mass of 1.4 M and a luminosity of 7 L, at a distance of some 11 light-years.

3) After Procyon comes Altair (Altair), A7IV-V, with a mass of 1.7-1.8 M and a luminosity of 10.6 L, at a distance of around 17 light-years.

4) Then we have Fomalhaut, A3V, with a mass 2 M and a luminosity of 16 L, at a distance of 25 light-years. Fomalhaut has a planet.

5) Then comes Sirius, A1V, with a mass of 2.12 M and a luminosity of 26 L, at a distance of 8.6 light-years.

6) Number six is Vega, A0V, with a mass of 2.3 M and a luminosity of 36 L, at a distance of 25 light-years.

7) Number seven is Castor, A1V, with a mass of 2.4 M and a luminosity of 37 L, at a distance of 51 light-years.

8) Number eight is Pollux, K0III, the first true giant on the list. Pollux has exhausted its core hydrogen and become a red giant, albeit a pale and faint one. Its mass is probably around 1.8 M and its luminosity is 46 L. Pollux has a planet.

Now it's getting complicated. Number 9 might be Capella, which consists of two components, 93 and 64 L, spectral classes G5III and G0III, with masses of 3.0 and 2.5 M, at a distance of 43 light-years. Both components are giants. Then again, number 9 might be Arcturus, spectral class K2III, which is a single star with a luminosity of 113 L (215 L is its infrared light is included) and a mass of about 1.5 M, at a distance of 37 light-years.

11) Number eleven is probably Regulus, spectral class B7IV-V, has a luminosity of 150 L (360 L if its ultravilolet light is taken into account) and a mass of 3.4 M, at a distance of 79 light-years.

12) Number 12 is probably Aldebaran, spectral class K5III, with a luminosity of some 160 L (425 L if infrared light is included) and a mass of 1.7 M, at a distance of 67 light-years.

13) Number 13 is probably Gacrux of spectral class M4III. Its optical luminosity is about 142 L, but its optical + infrared luminosity is about 1,500 L. The mass of Gacrux is about 3 M or less, and it is located at a distance of 88 light-years.

But I'm giving up now. The rest of the stars are all really bright and far away, and many or most of them are either binaries, or multiple stars, or giants, or supergiants. It is too hard to figure out exactly what their masses are, or exactly how bright they are, when you have to consider both their optical and their ultraviolet or infrared light.

Ann