My Herculis

Database links to My Herculis

Triple star My Herculis μ 1 / μ 2 Herculis
Observation data epoch : J2000.0
AladinLite
Constellation	Hercules
Vis. Brightness (total)	3.42 likes
Astrometry
Radial velocity	A: −17.07 ± 0.16 km / s B: −13.90 km / s C: −16.70 km / s
parallax	120.33 ± 0.16 mas
distance	27.105 ± 0.04 Lj (8.310 ± 0.01 pc )
period	A- B / C : 3445.0 a B - C: 43.2 a
Proper movement
Rec. Share:	A: −291.66 ± 0.12 mas / a BC: −343.35 ± 2.00 mas / a
Dec. portion:	A: −749.60 ± 0.15 mas / a BC: −743.88 ± 2.00 mas / a
Individual data
Names	A, B, C
Observation data:
Right ascension	A.	17h 46m 27.527s
	B.	17h 46m 25.079s
	C.	17h 46m 25.079s
declination	A.	+ 27 ° 43 ′ 14.44 ″
	B.	+ 27 ° 43 ′ 01.45 ″
	C.	+ 27 ° 43 ′ 01.45 ″
Apparent brightness	A.	3.49 m
	B.	10.20 m
	C.	10.70 m
Typing:
Spectral class	A.	G5.0IV
	B.	M3.0V
	C.	M4.0V
BV color index	A.	0.752
	B.	1,490
	C.	?
UB color index	A.	0.390
	B.	1.030
	C.	?
Astrometry:
Absolute visual brightness M vis	A.	3.73 mag
	B.	10.66 mag
	C.	11.10 mag
Physical Properties:
Dimensions	A.	1,100 M ☉
	B.	0.310 M ☉
	C.	0.310 M ☉
radius	A.	1.750 ± 0.03 R ☉
	B.	0.480 ± 0.10 R ☉
	C.	0.400 ± 0.10 R ☉
Luminosity	A.	2.65800 ± 0.1 L ☉
	B.	0.00445 L ☉
	C.	0.00294 L ☉
Effective temperature	A.	5520 K
	B.	3300 K
	C.	? K
Metallicity [Fe / H]	A.	+0.04
	B.	?
	C.	?
Rotation time	A.	4.30 d
	B.	? d
	C.	? d
Designations and catalog entries
Bayer-Bez.	μ Herculis
Flamsteed-Bez.	86 Herculis
Bonn diam.	BD + 27 ° 2888
Bright Star Cat.	HR 6623
HD catalog	HD 161797
SAO catalog	SAO 85397
Tycho catalog	TYC 2085/3062/1
Hipparcos catalog	HIP 86974
WDS catalog	WDS J17465 + 2743
ADS catalog	ADS 10786
Bonn diam.	A.	BD + 27 ° 2888 A
	B.	BD + 27 ° 2888 B
	C.	BD + 27 ° 2888 C
Bright Star Cat.	A.	HR 6623 A
	B.	HR 6623 B
	C.	HR 6623 C
HD catalog	A.	HD 161797 A
	B.	HD 161797 B
	C.	HD 161797 C

My Herculis (μ Herculis / μ Her) is a triple star system in the constellation Hercules . My Herculis ABC is 27.1 light years from the sun away and is one of the solar neighborhood systems . μ Herculis A, next to β Hydri the second next subgiant in spectral class G, is by far the brightest component and has an apparent brightness of at least 3.42; therefore it is easily visible to the naked eye.

Astrometry

Galactic orbit

My Herculis A, B, and C orbit the center of the Milky Way at a distance that varies between 16.758 and 25.437 light years (5,138 to 7,799  pc ), with an eccentricity of 0.206 ( major orbit half-axis 21,095 LJ (6,468 pc)). The current distance to the galactic center is 24,126 LJ (7,395 pc), the orbital speed relative to the sun is 36.2 km / s.

distance

The most precise measurement of the parallax of 120.33 ± 0.16 mas comes from the year 2007. This results in a distance of the system to the earth of 27.105 light years (1,714,200 AU ).

The proper motion in the sky that can be observed from earth is 0.814 ″ ( arc seconds ) annually .

Determining the distance for My Herculis

year	source	Parallax (mas)	Distance (pc)	Distance (Lj)	Distance ( Pm )
1970	Woolley et al.	128.00 ± 7.00	7.813 +0.45−0.41	25.481 +1.47−1.32	241.07 +13.95−12.50
1991	Gliese & Jahreiß	115.10 ± 5.40	8.689 +0.43−0.39	28.337 +1.39−1.27	268.09 +13.20−12.01
1995	Yale Parallax Catalog	118.80 ± 1.70	8.418 +0.12−0.12	27.454 + 0.40−0.39	259.74 +3.77−3.66
1997	Hipparcos catalog	119.05 ± 0.62	8.400 +0.04−0.04	27.397 +0.14−0.14	259.19 +1.36−1.34
1997	Tycho catalog	121.70 ± 2.00	8.217 +0.14−0.13	26.800 +0.45−0.43	253.55 +4.24−4.10
2007	van Leeuwen	120.33 ± 0.16	8.310 +0.01−0.01	27.105 +0.04−0.04	256.43 +0.34−0.34

Non-trigonometric distance determinations are marked in italics . The most precise determination is marked in bold .

My Herculis ABC system

The basic structure of the My Herculis system consists of two sub-systems: The My ¹ Herculis system consists of the luminous main star My Herculis A, in which astrometric measurements suggest a close companion, and My ² Herculis, a system of two red dwarf stars that common center of mass to the main star in a wide, elliptical orbit and thereby revolve around each other.

As a complete system, My Herculis belongs to the spectral class G5.0. The total mass of the system is about 1.92 solar masses (M☉).

Further designations of the overall system are Gliese 695, GC 24138, GCTP 4060.00, LDS 1002, STF 2220, ABT 14, AC 7, TRN 2 and 2MASS J17462752 + 2743142

My ¹ Herculis

So far, this subsystem only consists of the main star μ Herculis A; however, measurements indicate a cool companion (see below). Because of this, the star is also referred to as μ Herculis Aa . Due to the gravitational dominance of the main star, the common center of mass to the two distant red dwarfs of the My ² system is only 2.9 AU away from the main star.

Other common names are LHS 3326, LFT 1374, LTT 15266 and NLTT 45435.

My ² Herculis

The visual distance between the two components My Herculis B and C, which move the common center of mass in a wide, elliptical orbit , averages 34.0 arc seconds ( major orbit half-axis ). With the heliocentric distance of the two stars, this corresponds to 285.6 astronomical units (AU). They need 3445 years to go around My Herculis A together. Seen from Earth, its orbit is inclined by 247 ° .

My Herculis B and C are again at a distance of 1.0 " and 11.42 AU respectively in a moderately elliptical orbit (eccentricity 0.178), which varies from 9.39 to 13.45 AU. They need to go around a joint 43.2 years. The inclination of its orbit is 66.2 °.

As a system, they are classified in the spectral class M3.5V and have a total mass of 0.840 solar masses; their combined apparent magnitude is 9.78 mag.

Other common names are LHS 3325, LFT 1375, LTT 15267 and NLTT 45430.

Components

My Herculis A

The main star μ Herculis A, an astrophysical a yellow sub-giant , has an apparent magnitude of +3.49 like and belongs to the spectral class G5.0IV on. This star, which is basically not that different from the Sun, is an example of what the Sun might look like after it has depleted its hydrogen supply and has reached the end of its main sequence state and then begins to balloon into a red giant . My Herculis A is at a stage where the star is beginning to fuse its increasing amounts of helium in its core with the remaining hydrogen in its shell. Although its mass is 100 to 110% comparable with the mass of the sun , its diameter is comparatively high 1.750 solar radii ; this corresponds to 2,437,200 km in the total diameter of the star. Remarkably, due to the star's relative proximity to the Sun, this could be measured by directly measuring the angular distance of the star disk.

My Herculis A is 2.7 times more luminous than the sun. The metallicity of the star is slightly increased compared to the sun. The star is a bit cooler compared to the sun, the temperature is 5520 K (5247 ° C ).

Due to the age of the star (stars rotate faster with age), its speed of rotation is at least 10 times faster than that of the sun; the star's rotation is therefore at least 4.30 days. Because of this high rotation speed, it is still magnetically active and emits radiation in the X-ray range .

The Habitable Zone for My Herculis A was calculated to be 1.63 AU (slightly more than the distance between Mars and the Sun), which would correspond to an orbital period of about 2 years. A hypothetical planet with liquid water at this distance, which would have developed life when My Herculis A was still a main sequence star, might have been "roasted" today.

"Kneeling man"

The view of the night sky from such a hypothetical planet would in any case be impressive - the two faint companions My Herculis B & C would appear from there with a distance of about 0.5 ° and would have a brightness of about 2 full moons.

In the star catalog Calendarium of Al Achsasi Al Mouakket , My Herculis A bears the name Marfak Al Jathih Al Aisr , which was translated into Latin as Cubitum Sinistrum Ingeniculi ; it means "Kneeling Man's Left Elbow". In Chinese , the star is referred to as 天 市 左 垣 (Tiān Shì Zuǒ Yuán), 九 河 (Jiuhe, "nine rivers") and also as Kew Ho . In addition, the names Gliese 695 A, ADS 10786 A, Struve 2220 A and BD + 27 ° 2888 A are often used in various star catalogs.

My Herculis B

The star of the system My ² Herculis - μ Herculis B - belongs to the spectral class M3.0V and is classified as a red main sequence star, which is slightly brighter and larger with +10.20 mag . Its diameter is 0.48 solar radii ; this corresponds to approx. 668,500 km in the diameter of the star. The mass is 31% of the mass of the sun , whereas the luminosity is only 0.00445% of that of the sun. The temperature is a comparatively cool 3300 K (approx. 3000 ° C ).

The Habitable Zone for My Herculis B was calculated to be 0.0667 AU, which corresponds to an orbital period of approximately 8 days.

μ Herculis B also bears the names Gliese 695 B, ADS 10786 B, Struve 2220 B and BD + 27 ° 2888 B.

My Herculis C

The +10.70 mag bright companion star of the My ² Herculis system - μ Herculis C - belongs to the spectral class M4.0V and is also classified as a main sequence red dwarf. Its diameter is 0.40 solar radii ; this corresponds to approx. 557,100 km in the diameter of the star. The mass is 30% of the mass of the sun , whereas the luminosity is only 0.00294% of that of the sun.

The Habitable Zone for My Herculis B was calculated to be 0.0542 AU, which corresponds to an orbital period of approximately 6 days.

μ Herculis C is also called Gliese 695 C, ADS 10786 C, Struve 2220 C and BD + 27 ° 2888 C.

My Herculis ABC system

Surname	Another name	Spectral class	Coordinates	Angular distance as	Distance in AU	Eccentric	Apparent Helligk. like	Diameter R☉	Mass M☉	Temp. K
μ Herculis A 86 Herculis A	Gliese 695 A HD 161797 A	G5.0IV	17h 46m 27.527s + 27 ° 43 ′ 14.44 ″	0.00	0.00	?	3.49	1,750	1,100	5520
μ Herculis B 86 Herculis B	Gliese 695 A HD 161797 A	M3.0V	17h 46m 25.079s + 27 ° 43 ′ 01.45 ″	34.00	285.60	B / C 0.178	10.20	0.480	0.310	3300
μ Herculis C 86 Herculis C	Gliese 695 C HD 161797 C	M4.0V	17h 46m 25.079s + 27 ° 43 ′ 01.45 ″	34.00	285.60	B / C 0.178	10.70	0.400	0.300	?

Possibility of further stellar / substellar companions

My Herculis Ab?

In 1987, measurements showed that a potential companion of 0.15 solar masses (later corrected to 0.20) would have to be in a close orbit. However, it remains unclear whether it could be a cool red dwarf or a brown dwarf . This candidate cannot be resolved by a telescope due to its proximity to the outshining main star, so its composition and spectral class are very difficult to determine using current methods. The measurements showed a possible orbital period of 63 years (later corrected to 65 years) and an orbit inclination of 68 °.

The orbital period of 65 years results in a maximum distance of 17.2 AU to the main star. Because of the stated eccentricity of 0.34, the orbit would therefore vary between 11.4 and 23.0 AU.

In the case of the actual existence of this companion - if it is a red dwarf of the M5.0V class - the apparent magnitude of My ¹ Herculis would be 3.80 mag (A, Aa) or 10.10 (Ab) (according to another source 12.70 may). A confirmation for the existence of the companion has not yet been made.

My Herculis D?

In the Washington double star catalog as well as in the CCDM catalog, another, distant component "D" appears. This is a star with an apparent magnitude of 11.33 mag, which is visually 321.10 arc seconds (2002) from μ Herculis A. If this is a real companion, it would be at least 2100 AU away from the main star; this would result in an orbital period of 67,000 years. Because of this, and because of the much slower proper motion of this star, a physical connection to the My Herculis system is unlikely.

Closest neighbors

Surname	Another name	Spectral class	Distance LJ	Coordinates RA / DA	Apparent Helligk. like	Parallax mas	Sun distance LJ
Gliese 686 BD + 18 ° 3421	LHS 452 HIP 86287	M1.0V	4.5	17h 37m 53.347s + 18 ° 35 ′ 30.16 ″	9.58	123.67 ± 1.10	26,373
Gliese 1230 ABC G 184-19	LHS 3405 2MASS J18410977 + 2447143	M4.5V	6.5	18h 41m 09.776s + 24 ° 47 ′ 14.36 ″	12.40	130.20 ± 28.3	25.050
Wega α Lyrae	3 Lyr HD 172167	A0.0Va	7.3	18h 36m 56.336s + 38 ° 47 ′ 01.28 ″	0.03	130.23 ± 0.36	25.045
Gliese 649 BD + 25 ° 3173	LHS 3257 HIP 83043	M2.0V	8.5	16h 58m 08.850s + 25 ° 44 ′ 38.99 ″	9.66	96.67 ± 1.39	33.739
Gliese 638 HD 151288	BD + 33 ° 2777 HIP 82003	K7.0V	8.6	16h 45m 06.351s + 33 ° 30 ′ 33.22 ″	8.11	101.96 ± 0.71	31,989
Gliese 3991 AB G 203-47	HIP 83945 2MASS J17093153 + 4340531	M3.5V	8.6	17h 09m 31.544s + 43 ° 40 ′ 52.83 ″	11.78	134.31 ± 1.99	24.284
Gliese 694 BD + 43 ° 2796	LHS 3321 HIP 86776	M3.5V	8.7	17h 43m 55.963s + 43 ° 22 ′ 43.00 ″	10.51	105.50 ± 1.18	30.915
Gliese 3976 G 169-29	NLTT 43674 2MASS J16505794 + 2227058	M4.5V	8.9	16h 50m 57.950s + 22 ° 27 ′ 05.80 ″	14.11	100.00 ± 15.0	32.616
Gliese 745 A Ross 730	LHS 3432 HIP 93873	M2.0V	9.6	19h 07m 05.563s + 20 ° 53 ′ 16.97 ″	10.77	117.45 ± 2.28	27.770
Gliese 745 B Ross 731	LHS 3433 HD 349726	M2.0V	9.8	19h 07m 13.203s + 20 ° 52 ′ 37.24 ″	10.77	114.25 ± 2.30	28,548

Individual evidence

1. ↑ ^{a b c d} van Leeuwen F. (2007): HIP 86974 in the Hipparcos New Reduction catalog. Retrieved July 7, 2015 . 
2. ↑ ^{a b c d} Cutri et al. (2003): 2MASS J17462752 + 2743142 in the 2MASS All-Sky Catalog of Point Sources. Retrieved July 7, 2015 . 
3. ↑ ^{a b c d e f g h i j k} Gliese, W .; Jahreiß, H. (1991): Gliese 566 A & BC in the Nearby Stars Catalog. Retrieved July 7, 2015 . 
4. ↑ ^{a b c d e} ISDB (2001): Mu Herculis in the Stellar Database. Retrieved July 7, 2015 . 
5. ↑ ^{a b} Tokovinin A. (2008): Comparative statistics and origin of triple and quadruple stars. Retrieved July 7, 2015 . 
6. ↑ ^{a b} Turner, N. et al. (2001): Search for Faint Companions to Nearby Solar-like Stars . bibcode : 2001AJ .... 121.3254T .
7. ↑ ^{a b c d} Röser (2008): PPMX 174625.0 + 274301 in the PPMX Catalog of positions and proper motions. Retrieved July 7, 2015 . 
8. ↑ ^{a b c} Mason et al. (2001 - 2014): WDS 17465 + 2743 ABC in the Washington Visual Double Star Catalog. Retrieved July 7, 2015 . 
9. ↑ ^{a b c} Dommanget et al. (2002): CCDM 17465 + 2744 ABCD in the CCDM (Catalog of Components of Double & Multiple stars). Retrieved July 7, 2015 . 
10. ↑ ^{a b} Perryman et al. (1997): TYC 2085-3062-1 in the Hipparcos and Tycho Catalog. Retrieved July 7, 2015 . 
11. ↑ ^{a b} Kaler, J .: Mu Herculis with Jim Kaler. Retrieved July 7, 2015 . 
12. ^ ^{A b} Wanner J. et al .: Masses of the dwarf M Stars in the Mu Herculis System . 1967, bibcode : 1967AJ ..... 72Q.836W .
13. ↑ ^{a b c d} Piau L. et al. (2011): Surface convection and red-giant radius measurements. Retrieved July 7, 2015 . 
14. ↑ Pasinetti-Fracassini et al. (1988): Gliese 695 B in the Catalog of Stellar Diameters (CADARS). Retrieved July 7, 2015 . 
15. ↑ Pasinetti-Fracassini et al. (1988): Gliese 695 C in the Catalog of Stellar Diameters (CADARS). Retrieved July 7, 2015 . 
16. ↑ Morales JC et al. (2008): Gliese 695 B in Distances and atmospheric parameters of MSU stars . bibcode : 2008A & A ... 478..507M .
17. ↑ Ashland Astronomy Studio: Mu Herculis (HIP 86974). (No longer available online.) Archived from the original on September 23, 2015 ; Retrieved July 7, 2015 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  
18. ↑ Woolley et al. (1970): Woolley 695 ABC. Retrieved July 7, 2015 . 
19. ↑ Van Altena WF et al. (1995): GCTP 4060 in Yale Trigonometric Parallaxes. Retrieved July 7, 2015 . 
20. ↑ Perryman et al. (1997): HIP 86974 in The Hipparcos and Tycho Catalogs. Retrieved July 7, 2015 . 
21. ↑ Sol Company (1998 - 2002) PDF: My Herculis ABCD? at Solstation. Retrieved July 7, 2015 . 
22. ↑ SIMBAD: My Herculis A. Retrieved July 7, 2015 . 
23. ↑ ^{a b} SIMBAD: My Herculis BC. Retrieved July 7, 2015 . 
24. ↑ Heintz WD: BD + 27 ° 2888 in Binary and Proper Motion Stars . 1987, p. 1080 , bibcode : 1987AJ ..... 94.1077H .
25. ↑ Heintz WD: BD + 27 ° 2888 in Photographic astrometry of binary and proper-motion stars . 1987, p. 2346 , bibcode : 1994AJ .... 108.2338H .
26. ↑ SIMBAD: BD + 18 ° 3421. Retrieved July 7, 2015 . 
27. ↑ SIMBAD: GJ 1230. Accessed July 7, 2015 . 
28. ↑ SIMBAD: Alf Lyr. Retrieved July 7, 2015 . 
29. ↑ SIMBAD: BD + 25 ° 3173. Retrieved July 7, 2015 . 
30. ↑ SIMBAD: HD 151288. Retrieved July 7, 2015 . 
31. ↑ SIMBAD: G 203-47. Retrieved July 7, 2015 . 
32. ↑ SIMBAD: BD + 43 ° 2796. Retrieved July 7, 2015 . 
33. ↑ SIMBAD: GJ 3976. Accessed July 7, 2015 . 
34. ↑ SIMBAD: Ross 730. Retrieved July 7, 2015 . 
35. ↑ SIMBAD: HD 349726. Retrieved July 7, 2015 .