فوبوس (قمر)

فوبوس
Phobos
	Enhanced-color view of Phobos obtained by Mars Reconnaissance Orbiter on March 23, 2008.
الاكتشاف
اكتشفه	أساف هول
تاريخ الاكتشاف	18 أغسطس، 1877
التسميات
الأسماء البديلة	المريخ 1
الصفات	Phobian
السمات المدارية
	حقبة J2000
Periapsis	9,235.6 km (5,738.7 mi)
Apoapsis	9,518.8 km (5,914.7 mi)
Semi-major axis	9,377.2 km (5,826.7 mi)
Eccentricity	0.0151
Orbital period	0.31891023 d; (7 h 39.2 min)
Average orbital speed	2.138 km/s (1.328 mi/s)
Inclination	1.093° (to Mars's equator); 0.046° (to local Laplace plane); 26.04° (to the ecliptic)
Satellite of	Mars
السمات الطبيعية
الأبعاد	26.8 × 22.4 × 18.4 km (11.4 mi)
نصف القطر المتوسط	11.1 km (6.9 mi); (0.0021 Earths)
Mean radius	11.1 km (6.9 mi); (0.0021 Earths)
Surface area	~6,100 km2 (2,400 sq mi); (11.9 µEarths)
Volume	5,680 km3 (1,360 cu mi); (5.0 nEarths)
Mass	1.072×1016 kg; (1.8 nEarths)
Mean density	1.876 g/cm³
Surface gravity	0.0084–0.0019 m/s²; (8.4-1.9 mm/s²); (860-190 µg)
Escape velocity	11.3 m/s (40 km/h)
Rotation period	synchronous
Equatorial rotation velocity	11.0 km/h (6.8 mph) (at longest axis' tips)
Axial tilt	0°
Albedo	0.071
Temperature	~233 K
Apparent magnitude	11.3

فوبوس Phobos (تـُنطـَق /ˈfoʊbəs/ FOE-bəs، باليونانية Φόβος) (systematic designation: Mars I)أكبر وأقرب أقمار المريخ, والقمر الثاني هو ديموس. وقد تم اكتشافهما عام 1877. ويبلغ متوسط نصف قطر فوبوس 11.1 km (6.9 mi)، وتصل كتلته إلى 7.24 ضعف كتلة ديموس. وسمي على اسم الإله اليوناني فوبوس (ويعني "الخوف"), ابن أريس (المريخ).

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الاكتشاف

الخصائص الفيزيائية

A mosaic of three separate images taken by Viking 1 on October 19, 1978. The large crater (mostly in darkness) on the upper left is Stickney.

"Hollow Phobos" suggestions

خصائص جيولوجية مسماة

الحفر البركانية	التسمية	الاحداثيات
Clustril	Character in Gulliver's Travels	60°N 91°W / 60°N 91°W / 60; -91 (Clustril)
D'Arrest	Heinrich Louis d'Arrest, astronomer	39°S 179°W / 39°S 179°W / -39; -179 (D'Arrest)
Drunlo	Character in Gulliver's Travels	36°30′N 92°00′W / 36.5°N 92°W / 36.5; -92 (Drunlo)
Flimnap	Character in Gulliver's Travels	60°N 350°W / 60°N 350°W / 60; -350 (Flimnap)
Grildrig	Character in Gulliver's Travels	81°N 195°W / 81°N 195°W / 81; -195 (Grildrig)
Gulliver	Main character of Gulliver's Travels	62°N 163°W / 62°N 163°W / 62; -163 (Gulliver)
Hall	Asaph Hall, discoverer of Phobos	80°S 210°W / 80°S 210°W / -80; -210 (Hall)
Limtoc	Character in Gulliver's Travels	11°S 54°W / 11°S 54°W / -11; -54 (Limtoc)
Reldresal	Character in Gulliver's Travels	41°N 39°W / 41°N 39°W / 41; -39 (Reldresal)
Roche	Édouard Roche, astronomer	53°N 183°W / 53°N 183°W / 53; -183 (Roche)
Sharpless	Bevan Sharpless, astronomer	27°30′S 154°00′W / 27.5°S 154°W / -27.5; -154 (Sharpless)
Skyresh	Character in Gulliver's Travels	52°30′N 320°00′W / 52.5°N 320°W / 52.5; -320 (Skyresh)
Stickney	Angeline Stickney, wife of Asaph Hall	1°N 49°W / 1°N 49°W / 1; -49 (Stickney)
Todd	David Peck Todd, astronomer	9°S 153°W / 9°S 153°W / -9; -153 (Todd)
Wendell	Oliver Wendell, astronomer	1°S 132°W / 1°S 132°W / -1; -132 (Wendell)

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الخصائص المدارية

Orbits of Phobos and Deimos (to scale), seen from above Mars' north pole. Phobos is orbiting Mars 3.96 times faster than Deimos.

Phobos transits Sun, as seen by Mars Rover Opportunity

=العبور الشمسي

الفناء المستقبلي

المنشأ

Viking 1 image of Phobos, with Stickney Crater to the right

الاستكشاف

The Phobos monolith (right of center) as taken by the Mars Global Surveyor (MOC Image 55103) in 1998.

مهمات مستقبلية

انظر أيضا

المصادر

^ NASA Celestia
^ "Mars: Moons: Phobos". NASA Solar System Exploration. September 30, 2003. Retrieved August 18, 2008.
^ ^أ ^ب "Planetary Satellite Physical Parameters". JPL (Solar System Dynamics). July 13, 2006. Retrieved January 29, 2008.
^ "Mars Express closes in on the origin of Mars' larger moon". DLR. October 16, 2008. Retrieved October 16, 2008.
^ ^أ ^ب use a spherical radius of 11.1 km (6.9 mi); volume of a sphere * density of 1.877 g/cm³ yields a mass (m=d*v) of 1.07×10¹⁶ kg and an escape velocity (sqrt((2*g*m)/r)) of 11.3 m/s (40 km/h)
^ "Precise mass determination and the nature of Phobos". Geophysical Research Letters, Vol. 37. Retrieved May 31, 2010.
^ "Classic Satellites of the Solar System". Observatorio ARVAL. Retrieved September 28, 2007.

وصلات خارجية

[1] NASA Celestia

[NASA-2] "Mars: Moons: Phobos". NASA Solar System Exploration. September 30, 2003. Retrieved August 18, 2008.

[jplssd-3] أ ^ب "Planetary Satellite Physical Parameters". JPL (Solar System Dynamics). July 13, 2006. Retrieved January 29, 2008.

[dlr2008-4] "Mars Express closes in on the origin of Mars' larger moon". DLR. October 16, 2008. Retrieved October 16, 2008.

[estimate-5] أ ^ب use a spherical radius of 11.1 km (6.9 mi); volume of a sphere * density of 1.877 g/cm³ yields a mass (m=d*v) of 1.07×10¹⁶ kg and an escape velocity (sqrt((2*g*m)/r)) of 11.3 m/s (40 km/h)

[grl2010-6] "Precise mass determination and the nature of Phobos". Geophysical Research Letters, Vol. 37. Retrieved May 31, 2010.

[magnitude-7] "Classic Satellites of the Solar System". Observatorio ARVAL. Retrieved September 28, 2007.

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